Chapter 21: Instruction Encoding and ELF

Co-authored-by: godalming123 <68993177+godalming123@users.noreply.github.com>
Co-authored-by: tejasae-afk <tejasae-afk@users.noreply.github.com>
Co-authored-by: Tejas Attarde <201814263+tejasae-afk@users.noreply.github.com>
Co-authored-by: Tamás Hadházy <85063808+Hels15@users.noreply.github.com>
Co-authored-by: Hsiang-Ying Fu <66062782+fuhsnn@users.noreply.github.com>

230 files changed, 6485 insertions, 3875 deletions

diff --git a/src/main/java/com/seaofnodes/simple/IterPeeps.java b/src/main/java/com/seaofnodes/simple/IterPeeps.java
index 6208209f..66e8a4a8 100644
--- a/src/main/java/com/seaofnodes/simple/IterPeeps.java
+++ b/src/main/java/com/seaofnodes/simple/IterPeeps.java
@@ -49,6 +49,7 @@ public class IterPeeps {
 
     public IterPeeps( long seed ) { _work = new WorkList<>(seed); }
 
+    @SuppressWarnings("unchecked")
     public <N extends Node> N add( N n ) { return (N)_work.push(n); }
 
     public void addAll( Ary<Node> ary ) { _work.addAll(ary); }
@@ -126,6 +127,7 @@ public class IterPeeps {
      * Classic WorkList, with a fast add/remove, dup removal, random pull.
      * The Node's nid is used to check membership in the worklist.
      */
+    @SuppressWarnings("unchecked")
     public static class WorkList<E extends Node> {
 
         private Node[] _es;
diff --git a/src/main/java/com/seaofnodes/simple/Parser.java b/src/main/java/com/seaofnodes/simple/Parser.java
index 07f82625..219c3c44 100644
--- a/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/src/main/java/com/seaofnodes/simple/Parser.java
@@ -144,7 +144,25 @@ public class Parser {
 
         // Parse whole program, as-if function header "{ int arg -> body }"
         parseFunctionBody(_code._main,loc(),"arg");
-        _code.link(_code._main)._name = "main";
+
+        // Kill an empty default main.  Keep only if it was explicitly defined
+        // (programmer asked for a "main") or it has stuff (i.e. beginner
+        // default main).
+        FunNode main = _code.link(_code._main);
+        StopNode stop = _code._stop;
+        if( main.ret().expr() instanceof ConstantNode && main.ret().mem().in(0)==main  && stop.nIns() > 1 ) {
+            // Kill an empty default main; so it does not attempt to put a
+            // "main" in any final ELF file
+            stop.delDef(stop._inputs.find(main.ret()));
+        } else {
+            // We have a non-empty default main.
+            // Check for an explicit main
+            for( Node n : stop._inputs )
+                if( n instanceof FunNode fun && fun._name.equals("main") )
+                    // Found an explicit "main" AND we have a default "main"
+                    throw error("Cannot define both an explicit main and a default main");
+            main._name = "main";
+        }
 
         if( !_lexer.isEOF() ) throw _errorSyntax("unexpected");
 
@@ -154,7 +172,7 @@ public class Parser {
         for( StructNode init : INITS.values() )
             init.unkeep().kill();
         INITS.clear();
-        _code._stop.peephole();
+        stop.peephole();
         if( show ) showGraph();
     }
 
@@ -1407,6 +1425,7 @@ public class Parser {
 
         // Post-call setup
         CallEndNode cend = (CallEndNode)new CallEndNode(call).peephole();
+        call.peephole();        // Rerun peeps after CallEnd, allows early inlining
         // Control from CallEnd
         ctrl(new CProjNode(cend,0,ScopeNode.CTRL).peephole());
         // Memory from CallEnd
@@ -1669,6 +1688,7 @@ public class Parser {
             while( Character.isDigit(c=nextChar()) ) ;
             if( !(c=='e' || c=='.') )
                 return --_position - old;
+            if( peek() == '-' ) nextChar();
             while( Character.isDigit(c=nextChar()) || c=='e' || c=='.' ) ;
             return -(--_position - old);
         }
diff --git a/src/main/java/com/seaofnodes/simple/SB.java b/src/main/java/com/seaofnodes/simple/SB.java
index a45f0ddf..978fbed9 100644
--- a/src/main/java/com/seaofnodes/simple/SB.java
+++ b/src/main/java/com/seaofnodes/simple/SB.java
@@ -29,21 +29,28 @@ public final class SB {
   public SB p( int    s ) { _sb.append(s); return this; }
   public SB p( long   s ) { _sb.append(s); return this; }
   public SB p( boolean s) { _sb.append(s); return this; }
-  // 4 hex digits
-  public SB hex4(int s) {
-    assert (s>>4*4)==0; // Fits in 16 bits
-    for( int i=0; i<4; i++ ) {
-      int digit = (s>>((3-i)*4)) & 0xf;
-      _sb.append((char)((digit <= 9 ? '0' : ('A'-10))+digit));
-    }
+  // 1 byte, 2 hex digits, 8 bits
+  public SB hex1(int s) {
+    int digit = (s>>4) & 0xf;
+    _sb.append((char)((digit <= 9 ? '0' : ('A'-10))+digit));
+    digit = s & 0xf;
+    _sb.append((char)((digit <= 9 ? '0' : ('A'-10))+digit));
     return this;
   }
+  // 2 bytes, 4 hex digits, 16 bits, Big Endian
+  public SB hex2(int s) { return hex1(s>> 8).hex1(s); }
+  // 4 bytes, 8 hex digits, 32 bits, Big Endian
+  public SB hex4(int s) { return hex2(s>>16).hex2(s); }
+  // 8 bytes, 16 hex digits, 64 bits, Big Endian
+    public SB hex8(long s) { return hex4((int)(s>>32)).hex4((int)s); }
+
   // Fixed width field
   public SB fix( int sz, String s ) {
     for( int i=0; i<sz; i++ )
       _sb.append( i < s.length() ? s.charAt(i) : ' ');
     return this;
   }
+  public char at(int idx ) { return _sb.charAt(idx); }
 
   // Not spelled "p" on purpose: too easy to accidentally say "p(1.0)" and
   // suddenly call the autoboxed version.
@@ -83,6 +90,8 @@ public final class SB {
   //
   public SB unchar() { return unchar(1); }
   public SB unchar(int x) { _sb.setLength(_sb.length()-x); return this; }
+  public SB setLen(int len) { _sb.setLength(len); return this; }
+  public String subString(int start, int end ) { return _sb.substring(start,end); }
 
   public SB clear() { _sb.setLength(0); return this; }
   public int len() { return _sb.length(); }
diff --git a/src/main/java/com/seaofnodes/simple/codegen/BuildLRG.java b/src/main/java/com/seaofnodes/simple/codegen/BuildLRG.java
index 88b49863..e9b5eb2e 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/BuildLRG.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/BuildLRG.java
@@ -1,6 +1,5 @@
 package com.seaofnodes.simple.codegen;
 
-import com.seaofnodes.simple.Utils;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.TypeMem;
 
@@ -27,7 +26,7 @@ abstract public class BuildLRG {
                                 break;
                     // If none, make one.
                     if( lrg==null ) lrg = alloc.newLRG(n);
-                    if( phi instanceof MachNode mach ) defLRG(alloc,n);
+                    if( phi instanceof MachNode ) defLRG(alloc,n);
                     // Pass 2: everybody uses the same LRG
                     lrg=alloc.union(lrg,phi);
                     for( int i=phi instanceof ParmNode ? 2 : 1; i<n.nIns(); i++ )
@@ -55,8 +54,8 @@ abstract public class BuildLRG {
                         if( n.in(i)!=null ) {
                             LRG lrg2 = alloc.lrg(n.in(i));
                             if( lrg2 != null ) { // Anti-dep or other, no LRG
-                                RegMask use_mask = mach.regmap(i);
-                                if( !lrg2.machUse(mach,(short)i,use_mask.size1()).and(use_mask) )
+                                RegMask use_mask = mach.regmap(i); // use_mask is also null for anti-dep
+                                if( use_mask!=null && !lrg2.machUse(mach,(short)i,use_mask.size1()).and(use_mask) )
                                     alloc.fail(lrg2); // Empty register mask, must split
                             }
                         }
@@ -64,7 +63,7 @@ abstract public class BuildLRG {
                 }
 
                 // MultiNodes have projections which set registers
-                if( n instanceof MultiNode )
+                if( n instanceof MultiNode && !(n instanceof CFGNode) )
                     for( Node proj : n.outs() )
                         if( proj instanceof MachNode )
                             defLRG(alloc,proj);
diff --git a/src/main/java/com/seaofnodes/simple/codegen/Coalesce.java b/src/main/java/com/seaofnodes/simple/codegen/Coalesce.java
new file mode 100644
index 00000000..e2fac779
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/codegen/Coalesce.java
@@ -0,0 +1,105 @@
+package com.seaofnodes.simple.codegen;
+
+import com.seaofnodes.simple.Ary;
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.node.*;
+import java.util.BitSet;
+import java.util.IdentityHashMap;
+
+// Coalesce copies
+abstract public class Coalesce {
+
+    public static boolean coalesce( int round, RegAlloc alloc ) {
+
+        // Walk all the splits, looking for coalesce chances
+        boolean progress = false;
+        for( CFGNode bb : alloc._code._cfg ) {
+            outer:
+            for( int j=0; j<bb.nOuts(); j++ ) {
+                Node n = bb.out(j);
+                if( !(n instanceof SplitNode) ) continue;
+                LRG v1 = alloc.lrg(n);
+                LRG v2 = alloc.lrg(n.in(1));
+                if( v1 != v2 ) {
+                    LRG ov1 = v1, ov2 = v2;
+                    // Get the smaller neighbor count in v1
+                    if( v1.nadj() > v2.nadj() )
+                        { v1 = v2; v2 = alloc.lrg(n); }
+                    int v2len = v2._adj==null ? 0 : v2._adj._len;
+                    // See that they do not conflict (coalescing would make a self-conflict)
+                    if( v1._adj!=null && v2._adj!=null && v1._mask.overlap(v2._mask) ) {
+                        // Walk the smaller neighbors, and add to the larger.
+                        // Check for direct conflicts along the way.
+                        for( LRG v3 : v1._adj ) {
+                            if( v3==v2 ) {
+                                // Direct conflict, skip this LRG pair
+                                v2._adj.setLen(v2len);
+                                continue outer;
+                            }
+                            // Add missing LRGs from V1 to V2
+                            if( v2._adj.find(v3)== -1 )
+                                v2._adj.push(v3);
+                        }
+                    }
+                    // Most constrained mask
+                    RegMask mask = v1._mask==v2._mask ? v1._mask : v1._mask.copy().and(v2._mask);
+                    // Check for capacity
+                    if( v2.nadj() >= mask.size() ) {
+                        // Fails capacity, will not be trivial colorable
+                        if( v2._adj!=null ) v2._adj.setLen(v2len);
+                        continue;
+                    }
+
+                    // Union lrgs.
+                    progress = true;
+
+                    // Since `n` is dying, remove from the LRGS BEFORE doing
+                    // the union; this will let the union code keep the
+                    // matching bits from the other side, preserving some
+                    // info for biased coloring
+                    if( ov1. _machDef==n ) ov1. _machDef = null;
+                    if( ov1._splitDef==n ) ov1._splitDef = null;
+                    if( ov2. _machUse==n ) ov2. _machUse = null;
+                    if( ov2._splitUse==n ) ov2._splitUse = null;
+                    // Keep larger adjacency list.
+                    Ary<LRG> larger = v2._adj;
+                    v2._adj = null;
+
+                    // Union lrgs.  Swaps again, based on small lrg
+                    LRG vWin = v1.union(v2);
+                    vWin._adj = larger;
+                    LRG vLose = v1.leader() ? v2 : v1;
+
+                    // LRGs below v2len were always in v2, but maybe not in v1.
+                    // LRGs above v2len are in v1 but were not in v2.
+
+                    // Walk v2's neighbors, replacing vLose with vWin.
+                    if( larger != null )
+                        for( LRG vn : larger ) {
+                            int idx = vn._adj.find(vLose);
+                            if( idx != -1 )
+                                vn._adj.del(idx);
+                            if( vn._adj.find(vWin) == -1 )
+                                vn._adj.add(vWin);
+                        }
+                } else {
+
+                    // Since `n` is dying, remove from the LRGS
+                    if( v1. _machDef==n ) v1. _machDef=null;
+                    if( v1. _machUse==n ) v1. _machUse=null;
+                    if( v1._splitDef==n ) v1._splitDef=null;
+                    if( v1._splitUse==n ) v1._splitUse=null;
+                }
+
+                // Remove junk split
+                n.removeSplit();
+                j--;
+            }
+        }
+
+        if( progress )
+            alloc.unify();
+
+        return true;
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java b/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java
index a1294890..9ec3bc7b 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java
@@ -4,11 +4,14 @@ import com.seaofnodes.simple.*;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.print.*;
 import com.seaofnodes.simple.type.*;
+import java.io.IOException;
 import java.util.BitSet;
 import java.util.HashMap;
 import java.util.IdentityHashMap;
 
+@SuppressWarnings("unchecked")
 public class CodeGen {
+    public static final String PORTS = "com.seaofnodes.simple.node.cpus";
     // Last created CodeGen as a global; used all over to avoid passing about a
     // "context".
     public static CodeGen CODE;
@@ -17,11 +20,13 @@ public class CodeGen {
         Parse,                  // Parse ASCII text into Sea-of-Nodes IR
         Opto,                   // Run ideal optimizations
         TypeCheck,              // Last check for bad programs
+        LoopTree,               // Build a loop tree; break infinite loops
         InstSelect,             // Convert to target hardware nodes
         Schedule,               // Global schedule (code motion) nodes
         LocalSched,             // Local schedule
         RegAlloc,               // Register allocation
         Encoding,               // Encoding
+        Export,                 // Export
     }
     public Phase _phase;
 
@@ -30,7 +35,6 @@ public class CodeGen {
     public final String _src;
     // Compile-time known initial argument type
     public final TypeInteger _arg;
-
     // ---------------------------
     public CodeGen( String src ) { this(src, TypeInteger.BOT, 123L ); }
     public CodeGen( String src, TypeInteger arg, long workListSeed ) {
@@ -46,6 +50,27 @@ public class CodeGen {
     }
 
 
+    // All passes up to Phase, except ELF
+    public CodeGen driver( Phase phase ) { return driver(phase,null,null); }
+    public CodeGen driver( Phase phase, String cpu, String callingConv ) {
+        if( _phase==null )                       parse();
+        if( _phase.ordinal() < phase.ordinal() ) opto();
+        if( _phase.ordinal() < phase.ordinal() ) typeCheck();
+        if( _phase.ordinal() < phase.ordinal() ) loopTree();
+        if( _phase.ordinal() < phase.ordinal() && cpu != null ) instSelect(cpu,callingConv);
+        if( _phase.ordinal() < phase.ordinal() ) GCM();
+        if( _phase.ordinal() < phase.ordinal() ) localSched();
+        if( _phase.ordinal() < phase.ordinal() ) regAlloc();
+        if( _phase.ordinal() < phase.ordinal() ) encode();
+        return this;
+    }
+
+    // Run all the phases through final ELF emission
+    public CodeGen driver( String cpu, String callingConv, String obj ) throws IOException {
+        return driver(Phase.Encoding,cpu,callingConv).exportELF(obj);
+    }
+
+
     // ---------------------------
     /**
      *  A counter, for unique node id generation.  Starting with value 1, to
@@ -62,6 +87,24 @@ public class CodeGen {
     public  int getALIAS() { return _alias++; }
 
 
+    // idepths are cached and valid until *inserting* CFG edges (deleting is
+    // OK).  This happens with inlining, which bumps the version to bulk
+    // invalidate the idepth caches.
+    private int _iDepthVersion = 0;
+    public void invalidateIDepthCaches() { _iDepthVersion++; }
+    public boolean validIDepth(int idepth) {
+        if( idepth==0 ) return false;
+        if( _iDepthVersion==0 ) return true;
+        return (idepth%100)==_iDepthVersion;
+    }
+    public int iDepthAt(int idepth) {
+        return 100*idepth+_iDepthVersion;
+    }
+    public int iDepthFrom(int idepth) {
+        assert idepth==0 || validIDepth(idepth);
+        return idepth+100;
+    }
+
     // Popular visit bitset, declared here, so it gets reused all over
     public final BitSet _visit = new BitSet();
     public BitSet visit() { assert _visit.isEmpty(); return _visit; }
@@ -154,7 +197,7 @@ public class CodeGen {
 
     // ---------------------------
     // Last check for bad programs
-    int _tTypeCheck;
+    public int _tTypeCheck;
     public CodeGen typeCheck() {
         // Demand phase Opto for cleaning up dead control flow at least,
         // required for the following GCM.
@@ -169,17 +212,42 @@ public class CodeGen {
         return this;
     }
 
+    // ---------------------------
+    // Build the loop tree; break never-exit loops
+    public int _tLoopTree;
+    public CodeGen loopTree() {
+        assert _phase.ordinal() <= Phase.TypeCheck.ordinal();
+        _phase = Phase.LoopTree;
+        long t0 = System.currentTimeMillis();
+        // Build the loop tree, fix never-exit loops
+        _start.buildLoopTree(_stop);
+        _tLoopTree = (int)(System.currentTimeMillis() - t0);
+        return this;
+    }
 
     // ---------------------------
     // Code generation CPU target
     public Machine _mach;
-    //
+    // Chosen calling convention (usually either Win64 or SystemV)
     public String _callingConv;
+    // Callee save registers
+    public RegMask _callerSave;
+
+    // All returns have the following inputs:
+    // 0 - ctrl
+    // 1 - memory
+    // 2 - varies with returning GPR,FPR
+    // 3 - RPC
+    // 4+- Caller save registers
+    public RegMask[] _retMasks;
+    // Return Program Counter
+    public RegMask _rpcMask;
 
     // Convert to target hardware nodes
     public int _tInsSel;
-    public CodeGen instSelect( String base, String cpu, String callingConv ) {
-        assert _phase.ordinal() <= Phase.TypeCheck.ordinal();
+    public CodeGen instSelect( String cpu, String callingConv ) { return instSelect(cpu,callingConv,PORTS); }
+    public CodeGen instSelect( String cpu, String callingConv, String base ) {
+        assert _phase.ordinal() == Phase.LoopTree.ordinal();
         _phase = Phase.InstSelect;
 
         _callingConv = callingConv;
@@ -188,9 +256,30 @@ public class CodeGen {
         // Look for CPU in fixed named place:
         //   com.seaofnodes.simple.node.cpus."cpu"."cpu.class"
         String clzFile = base+"."+cpu+"."+cpu;
-        try { _mach = ((Class<Machine>) Class.forName( clzFile )).getDeclaredConstructor().newInstance(); }
+        try { _mach = ((Class<Machine>) Class.forName( clzFile )).getDeclaredConstructor(new Class[]{CodeGen.class}).newInstance(this); }
         catch( Exception e ) { throw new RuntimeException(e); }
 
+        // Build global copies of common register masks.
+        long callerSave = _mach.callerSave();
+        long  neverSave = _mach. neverSave();
+        int maxReg = Math.min(64,_mach.regs().length);
+        assert maxReg>=64 || (-1L << maxReg & callerSave)==0; // No stack slots in callerSave
+        _callerSave = new RegMask(callerSave);
+
+        // Build a Return RegMask array.  All returns have the following inputs:
+        // 0 - ctrl
+        // 1 - memory
+        // 2 - varies with returning GPR,FPR
+        // 3 - RPC
+        // 4+- Caller save registers
+        _retMasks = new RegMask[(maxReg-_callerSave.size()-Long.bitCount( neverSave ))+4];
+        for( int reg=0, i=4; reg<maxReg; reg++ )
+            if( !_callerSave.test(reg) && ((1L<<reg)&neverSave)==0 )
+                _retMasks[i++] = new RegMask(reg);
+        _rpcMask = new RegMask(_mach.rpc());
+        _retMasks[3] = _rpcMask;
+
+
         // Convert to machine ops
         long t0 = System.currentTimeMillis();
         _uid = 1;               // All new machine nodes reset numbering
@@ -226,7 +315,7 @@ public class CodeGen {
         for( int i=0; i < x.nIns(); i++ )
             x._inputs.set(i, _instSelect(x.in(i),map) );
         if( x instanceof MachNode mach )
-            mach.postSelect();  // Post selection action
+            mach.postSelect(this);  // Post selection action
 
         // Updates forward edges only.
         n._outputs.clear();
@@ -246,8 +335,8 @@ public class CodeGen {
 
 
     // ---------------------------
-    // Control Flow Graph in RPO order.
-    int _tGCM;
+    // Control Flow Graph in Reverse Post Order.
+    public int _tGCM;
     public Ary<CFGNode> _cfg = new Ary<>(CFGNode.class);
 
     // Global schedule (code motion) nodes
@@ -257,8 +346,6 @@ public class CodeGen {
         _phase = Phase.Schedule;
         long t0 = System.currentTimeMillis();
 
-        // Build the loop tree, fix never-exit loops
-        _start.buildLoopTree(_stop);
         GlobalCodeMotion.buildCFG(this);
         _tGCM = (int)(System.currentTimeMillis() - t0);
         if( show )
@@ -268,7 +355,7 @@ public class CodeGen {
 
     // ---------------------------
     // Local (basic block) scheduler phase, a classic list scheduler
-    int _tLocal;
+    public int _tLocal;
     public CodeGen localSched() {
         assert _phase == Phase.Schedule;
         _phase = Phase.LocalSched;
@@ -281,7 +368,7 @@ public class CodeGen {
 
     // ---------------------------
     // Register Allocation
-    int _tRegAlloc;
+    public int _tRegAlloc;
     public RegAlloc _regAlloc;
     public CodeGen regAlloc() {
         assert _phase == Phase.LocalSched;
@@ -292,31 +379,46 @@ public class CodeGen {
         _tRegAlloc = (int)(System.currentTimeMillis() - t0);
         return this;
     }
-    public String reg(Node n) {
+
+    // Human readable register name
+    public String reg(Node n) { return reg(n,null); }
+    public String reg(Node n, FunNode fun) {
         if( _phase.ordinal() >= Phase.RegAlloc.ordinal() ) {
-            String s = _regAlloc.reg(n);
+            String s = _regAlloc.reg(n,fun);
             if( s!=null ) return s;
         }
         return "N"+ n._nid;
     }
 
+
     // ---------------------------
     // Encoding
-    int _tEncode;
+    public int _tEncode;
+    public Encoding _encoding;   // Encoding object
+    public void preEncode() {  } // overridden by alternative ports
     public CodeGen encode() {
         assert _phase == Phase.RegAlloc;
         _phase = Phase.Encoding;
         long t0 = System.currentTimeMillis();
+        _encoding = new Encoding(this);
+        preEncode();
+        _encoding.encode();
+        _tEncode = (int)(System.currentTimeMillis() - t0);
+        return this;
+    }
 
-
-        //_tEncode = (int)(System.currentTimeMillis() - t0);
-        //throw Utils.TODO();
+    // ---------------------------
+    // Exporting to external formats
+    public CodeGen exportELF(String fname) throws IOException {
+        assert _phase == Phase.Encoding;
+        _phase = Phase.Export;
+        if( fname == null ) new LinkMem(this).link(); // In memory patching
+        else new ElfFile(this).export(fname); // External ELF file
         return this;
     }
-    // Encoded binary, no relocation info
-    public byte[] binary() { throw Utils.TODO(); }
 
     // ---------------------------
+    public boolean _asmLittle=true;
     SB asm(SB sb) { return ASMPrinter.print(sb,this); }
     public String asm() { return asm(new SB()).toString(); }
 
@@ -335,4 +437,44 @@ public class CodeGen {
 
     // Debugging helper
     public Node f(int idx) { return _stop.find(idx); }
+
+
+    String printCFG() {
+        if( _cfg==null ) return "no CFG";
+        SB sb = new SB();
+        for( CFGNode cfg : _cfg )
+            IRPrinter.printLine(cfg,sb);
+        return sb.toString();
+    }
+
+    public static void print_as_hex(Encoding enc) {
+        for (byte b : enc._bits.toByteArray()) {
+            System.out.print(String.format("%02X", b));
+        }
+        System.out.println();
+    }
+
+    public void print_as_hex() {
+        for (byte b : _encoding._bits.toByteArray()) {
+            System.out.print(String.format("%02X", b));
+        }
+        System.out.println();
+    }
+
+    //// Debug purposes for now
+//    public CodeGen printENCODING() {
+//        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+//
+//        for(Node bb : CodeGen.CODE._cfg) {
+//            for(Node n: bb.outs()) {
+//                if(n instanceof MachNode) {
+//                    ((MachNode) n).encoding(E);
+//                }
+//            }
+//        }
+//
+//        print_as_hex(outputStream);
+//        // Get the raw bytes from the output stream
+//        return this;
+//    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/codegen/ElfExpr.java b/src/main/java/com/seaofnodes/simple/codegen/ElfExpr.java
new file mode 100644
index 00000000..9d9b8a1c
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/codegen/ElfExpr.java
@@ -0,0 +1,87 @@
+package com.seaofnodes.simple.codegen;
+
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+
+public class ElfExpr {
+    public static void main(String[] args) {
+        try (FileOutputStream fos = new FileOutputStream("hello.o")) {
+            ByteBuffer buffer = ByteBuffer.allocate(512);
+            buffer.order(ByteOrder.LITTLE_ENDIAN);
+
+            // === ELF HEADER (64 bytes) ===
+            buffer.put(new byte[]{
+                    0x7F, 'E', 'L', 'F',  // ELF Magic
+                    2, 1, 1, 0,          // 64-bit, little-endian, version
+                    0, 0, 0, 0, 0, 0, 0,  // ABI padding
+                    2, 0,                // Type: Executable (ET_EXEC)
+                    0x3E, 0x00,          // Machine: x86-64
+                    1, 0, 0, 0,          // ELF version
+                    0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // Entry point
+                    0, 0, 0, 0, 0, 0, 0, 0,  // Program header offset
+                    64, 0, 0, 0, 0, 0, 0, 0,  // Section header offset
+                    0, 0, 0, 0,            // Flags
+                    64, 0,                 // ELF header size
+                    0, 0,                   // Program header entry size
+                    0, 0,                   // Number of program header entries
+                    40, 0,                  // Section header entry size
+                    2, 0,                   // Number of section headers
+                    1, 0                    // Section header string table index
+            });
+
+            // === .TEXT SECTION (Executable Code) ===
+            byte[] textSection = {
+                    // sys_write (write(1, message, 13))
+                    (byte) 0x48, (byte) 0xC7, (byte) 0xC0, 0x01, 0x00, 0x00, 0x00,  // mov rax, 1
+                    (byte) 0x48, (byte) 0xC7, (byte) 0xC7, 0x01, 0x00, 0x00, 0x00,  // mov rdi, 1
+                    (byte) 0x48, (byte) 0xBE, (byte)0x90, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // mov rsi, message
+                    (byte) 0x48, (byte) 0xC7, (byte) 0xC2, 0x0D, 0x00, 0x00, 0x00,  // mov rdx, 13
+                    (byte) 0x0F, (byte) 0x05,  // syscall
+
+                    // sys_exit (exit(0))
+                    (byte) 0x48, (byte) 0xC7, (byte) 0xC0, 0x3C, 0x00, 0x00, 0x00,  // mov rax, 60
+                    (byte) 0x48, (byte) 0x31, (byte) 0xFF,  // xor rdi, rdi
+                    (byte) 0x0F, (byte) 0x05   // syscall
+            };
+
+            // Append section data
+            buffer.position(256);
+            buffer.put(textSection);
+
+            // === STRING MESSAGE (.data Section) ===
+            byte[] message = "Hello, World!\n".getBytes();
+            buffer.position(400);
+            buffer.put(message);
+
+            // === SECTION HEADERS ===
+            buffer.position(64);
+
+            // Null Section (required as first entry)
+            buffer.put(new byte[40]);
+
+            // .text Section
+            buffer.putInt(1);    // Offset in section string table (".text")
+            buffer.putInt(1);    // Type: SHT_PROGBITS
+            buffer.putLong(6);   // Flags: Executable | Allocatable
+            buffer.putLong(0);   // Virtual address
+            buffer.putLong(256); // Offset to section data
+            buffer.putLong(textSection.length); // Section size
+            buffer.putInt(0);    // Link
+            buffer.putInt(0);    // Info
+            buffer.putLong(4);   // Address alignment
+            buffer.putLong(0);   // No extra entries
+
+            // === SECTION HEADER STRING TABLE ===
+            buffer.position(500);
+            buffer.put(".text".getBytes());
+            buffer.put((byte) 0x00);  // Null terminator
+
+            fos.write(buffer.array());
+            System.out.println("ELF object file 'hello.o' created.");
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java b/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java
new file mode 100644
index 00000000..746ecfed
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java
@@ -0,0 +1,381 @@
+package com.seaofnodes.simple.codegen;
+
+import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.codegen.Encoding.BAOS;
+import java.io.*;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.util.HashMap;
+import java.util.Map;
+
+public class ElfFile {
+
+    final CodeGen _code;
+    Ary<Section> _sections = new Ary<>(Section.class);
+
+    ElfFile( CodeGen code ) { _code = code; }
+
+    public static int writeCString(DataSection strtab, String name) {
+        // place name in the string table
+        int pos = strtab._contents.size();
+        byte[] name_bytes = name.getBytes();
+        strtab._contents.write(name_bytes, 0, name_bytes.length);
+        // the strings are null terminated
+        strtab._contents.write(0);
+        return pos;
+    }
+
+    public static void write4( ByteArrayOutputStream bits, int op ) {
+        bits.write(op    );
+        bits.write(op>> 8);
+        bits.write(op>>16);
+        bits.write(op>>24);
+    }
+    public static void write8( ByteArrayOutputStream bits, long i64 ) {
+        write4(bits, (int) i64     );
+        write4(bits, (int)(i64>>32));
+    }
+
+    public static final int SYMBOL_SIZE = 4+1+1+2+8+8;
+
+    public static final int SYM_BIND_LOCAL   = 0;
+    public static final int SYM_BIND_GLOBAL  = 1;
+    public static final int SYM_BIND_WEAK    = 2;
+
+    public static final int SYM_TYPE_NOTYPE  = 0;
+    public static final int SYM_TYPE_OBJECT  = 1;
+    public static final int SYM_TYPE_FUNC    = 2;
+    public static final int SYM_TYPE_SECTION = 3;
+
+    public static class Symbol {
+        String _name;
+        int _name_pos;
+
+        // index in the symbol table
+        int _index;
+
+        // which section is it in
+        int _parent;
+
+        // depends on the symbol type
+        //   TODO
+        int _value, _size;
+
+        // top 4bits are the "bind", bottom 4 are "type"
+        int _info;
+
+        // bind 1011
+        // 00001111
+        // 10110000
+
+        Symbol(String name, int parent, int bind, int type) {
+            _name = name;
+            _parent = parent;
+            _info = (bind << 4) | (type & 0xF);
+        }
+
+        void writeHeader(ByteBuffer out) {
+            out.putInt(_name_pos);         // name
+            out.put((byte) _info);         // info
+            // default visibility
+            out.put((byte) 0);             // other
+            out.putShort((short) _parent); // shndx
+            out.putLong(_value);           // value
+            out.putLong(_size);            // size
+        }
+    }
+
+    public static final int SHF_WRITE     = 1;
+    public static final int SHF_ALLOC     = 2;
+    public static final int SHF_EXECINSTR = 4;
+    public static final int SHF_STRINGS   = 32;
+    public static final int SHF_INFO_LINK = 64;
+
+    public static final int SECTION_HDR_SIZE = 64;
+    abstract public static class Section {
+        String _name;
+        int _index;
+
+        int _type, _flags;
+        int _link, _info;
+
+        // where's the name in the string table
+        int _name_pos;
+        int _file_offset;
+
+        Section(String name, int type) {
+            _name = name;
+            _type = type;
+        }
+
+        void writeHeader(ByteBuffer out) {
+            out.putInt(_name_pos);     // name
+            out.putInt(_type);         // type
+            out.putLong(_flags);       // flags
+            out.putLong(0);            // addr
+            out.putLong(_file_offset); // offset
+            out.putLong(size());       // size
+            out.putInt(_link);         // link
+            out.putInt(_info);         // info
+            out.putLong(16);           // addralign
+            if (_type == 2) {
+                out.putLong(SYMBOL_SIZE);// entsize
+            } else if (_type == 4) {
+                out.putLong(24);         // entsize
+            } else {
+                out.putLong(0);          // entsize
+            }
+        }
+
+        abstract void write(ByteBuffer out);
+        abstract int size();
+    }
+
+    public static class SymbolSection extends Section {
+        Ary<Symbol> _symbols = new Ary<>(Symbol.class);
+        Ary<Symbol> _loc = new Ary<>(Symbol.class);
+
+        SymbolSection(String name, int type) {
+            super(name, type);
+        }
+
+        @Override
+        void writeHeader(ByteBuffer out) {
+            // points to string table section
+            _link = 1;
+
+            // number of non-local symbols
+            _info = _loc.len() + 1;
+
+            super.writeHeader(out);
+        }
+
+        void push(Symbol s) {
+            if ((s._info >> 4) != SYM_BIND_LOCAL) {
+                _symbols.push(s);
+            } else {
+                _loc.push(s);
+            }
+        }
+
+        @Override
+        void write(ByteBuffer out) {
+            // Index 0 both designates the first entry in the table and serves as the undefined symbol index
+            for( int i = 0; i < SYMBOL_SIZE/4; i++ ) {
+                out.putInt(0);
+            }
+            // index is already set
+            for( Symbol s : _loc ) {
+                s.writeHeader(out);
+            }
+            for( Symbol s : _symbols ) {
+                s.writeHeader(out);
+            }
+        }
+
+        @Override
+        int size() {
+            return (1 + _symbols.len() + _loc.len()) * SYMBOL_SIZE;
+        }
+    }
+
+    public static class DataSection extends Section {
+        ByteArrayOutputStream _contents;
+
+        DataSection(String name, int type) {
+            super(name, type);
+            _contents = new ByteArrayOutputStream();
+        }
+
+        DataSection(String name, int type, ByteArrayOutputStream contents) {
+            super(name, type);
+            _contents = contents;
+        }
+
+        @Override
+            void write(ByteBuffer out) {
+            out.put(_contents.toByteArray());
+        }
+
+        @Override
+            int size() {
+            return _contents.size();
+        }
+    }
+
+    private void pushSection(Section s) {
+        _sections.push(s);
+        // ELF is effectively "1-based", due to the NULL section
+        s._index = _sections._len;
+    }
+
+    /* creates function and stores where it starts*/
+    private final HashMap<TypeFunPtr,Symbol> _funcs = new HashMap<>();
+    private void encodeFunctions(SymbolSection symbols, DataSection text) {
+        for( int i=0; i<_code._cfg._len; i++ ) {
+            if( !(_code._cfg.at(i) instanceof FunNode fun) ) continue;
+            // skip until the function ends
+            while( !(_code._cfg.at(i) instanceof ReturnNode ret) )
+                i++;
+            int end = _code._encoding._opStart[ret._nid] + _code._encoding._opLen[ret._nid];
+
+            Symbol func = new Symbol(fun._name, text._index, SYM_BIND_GLOBAL, SYM_TYPE_FUNC);
+            func._value = _code._encoding._opStart[fun._nid];
+            func._size = end - func._value;
+            symbols.push(func);
+            _funcs.put(fun.sig(), func);
+        }
+    }
+
+    public void export(String fname) throws IOException {
+        DataSection strtab = new DataSection(".strtab", 3 /* SHT_SYMTAB */);
+        // first byte is reserved for an empty string
+        strtab._contents.write(0);
+        pushSection(strtab);
+
+        // place all the symbols
+        SymbolSection symbols = new SymbolSection(".symtab", 2 /* SHT_STRTAB */);
+        pushSection(symbols);
+
+        // zero flag by default
+        // we've already constructed this entire section in the encoding phase
+        DataSection text = new DataSection(".text", 1 /* SHT_PROGBITS */, _code._encoding._bits);
+        text._flags = SHF_ALLOC | SHF_WRITE | SHF_EXECINSTR;
+        pushSection(text);
+
+        // Build and write constant pool
+        BAOS cpool = new BAOS();
+        Encoding enc = _code._encoding;
+        enc.writeConstantPool(cpool,false);
+        DataSection rdata = new DataSection(".rodata", 1 /* SHT_PROGBITS */, cpool);
+        rdata._flags = SHF_ALLOC;
+        pushSection(rdata);
+
+        // populate function symbols
+        encodeFunctions(symbols, text);
+
+        int idx = 1;
+        for( Section s : _sections ) {
+            Symbol sym = new Symbol(s._name, idx++, SYM_BIND_LOCAL, SYM_TYPE_SECTION);
+            // we can reuse the same name pos from the actual section
+            sym._name_pos = s._name_pos;
+            sym._size = s.size();
+            symbols.push(sym);
+        }
+
+        // calculate local index
+        int num = 1;
+        for( Symbol s : symbols._loc )
+            s._index = num++;
+        // extra space for .rela.text
+        int start_global = num+1; // Add one to skip the final .rela.text local symbol
+        for( Symbol a: symbols._symbols )
+            a._index = start_global++;
+        int bigConIdx = start_global;
+        start_global += enc._bigCons.size();
+
+        // create .text relocations
+        DataSection text_rela = new DataSection(".rela.text", 4 /* SHT_RELA */);
+        for( Node n : enc._externals.keySet()) {
+            int nid    = n._nid;
+            String extern = enc._externals.get(n);
+
+            Symbol sym = new Symbol(extern, 0, SYM_BIND_GLOBAL, SYM_TYPE_NOTYPE);
+            sym._index = start_global++;
+            symbols.push(sym);
+
+            int offset = enc._opStart[nid] + enc._opLen[nid] - 4;
+
+            // u64 offset
+            write8(text_rela._contents, offset);
+            // u64 info
+            write8(text_rela._contents, ((long)sym._index << 32L) | 4L /* PLT32 */);
+            // i64 addend
+            write8(text_rela._contents, -4);
+        }
+
+        // Write relocations for the constant pool
+        for( Encoding.Relo relo : enc._bigCons.values() ) {
+            Symbol glob = new Symbol("GLOB$"+bigConIdx, rdata._index, SYM_BIND_GLOBAL, SYM_TYPE_FUNC);
+            glob._value = relo._target;
+            glob._size = 1 << relo._t.log_size();
+            glob._index = bigConIdx++;
+            symbols.push(glob);
+            write8(text_rela._contents, relo._opStart+relo._off);
+            write8(text_rela._contents, ((long)glob._index << 32L) | relo._elf );
+            write8(text_rela._contents, -4);
+        }
+
+        text_rela._flags = SHF_INFO_LINK;
+        text_rela._link = 2;
+        text_rela._info = text._index;
+        pushSection(text_rela);
+
+        Symbol sym = new Symbol(text_rela._name, num++, SYM_BIND_LOCAL, SYM_TYPE_SECTION);
+        sym._name_pos = text_rela._name_pos;
+        sym._size = text_rela.size();
+        symbols.push(sym);
+
+        // populate string table
+        for( Section s : _sections ) { s._name_pos = writeCString(strtab, s._name); }
+        for( Symbol s : symbols._symbols ) { s._name_pos = writeCString(strtab, s._name); }
+        for( Symbol s : symbols._loc ) { s._name_pos = writeCString(strtab, s._name); }
+
+        int size = 64; // ELF header
+        // size of all section data
+        for( Section s : _sections ) {
+            s._file_offset = size;
+            size += s.size();
+        }
+        // headers go at the very end
+        int shdr_offset = size;
+        // there's a "null" section at the start of the section headers
+        size += SECTION_HDR_SIZE*(1 + _sections.len());
+
+        // System.out.printf("Hello %d, %d, %s\n", size, shdr_offset);
+        ByteBuffer out = ByteBuffer.allocate(size);
+        out.order(ByteOrder.LITTLE_ENDIAN);
+
+        // ELF header
+        out.put(new byte[]{ 0x7F, 'E', 'L', 'F', 2, 1, 1, 0 });
+        out.put(new byte[8]);
+        out.putShort((short)1 /* ET_REL */); // type
+        out.putShort((short)62 /* AMD64 */); // machine
+        out.putInt(1);                // version
+        out.putLong(0);               // entry
+        out.putLong(0);               // phoff
+        out.putLong(shdr_offset);     // shoff
+        out.putInt(0);                // flags
+        out.putShort((short)64);      // ehsize
+        out.putShort((short)0);       // phentsize
+        out.putShort((short)0);       // phnum
+        out.putShort((short)64);      // shentsize
+        out.putShort((short) (1 + _sections.len())); // shnum
+        out.putShort((short)1);       // shstrndx
+
+        // raw section data
+        for( Section s : _sections ) {
+            s.write(out);
+        }
+
+        // "null" section
+        for( int i = 0; i < 16; i++ ) {
+            out.putInt(0);
+        }
+
+        for( Section s : _sections ) {
+            s.writeHeader(out);
+        }
+        assert out.position() == size;
+
+        File file = new File(fname);
+        if( file.getParentFile()!=null )
+          file.getParentFile().mkdirs();
+        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file));
+        bos.write(out.array());
+        bos.close();
+    }
+
+}
diff --git a/src/main/java/com/seaofnodes/simple/codegen/Encoding.java b/src/main/java/com/seaofnodes/simple/codegen/Encoding.java
new file mode 100644
index 00000000..c35ea6a4
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/codegen/Encoding.java
@@ -0,0 +1,473 @@
+package com.seaofnodes.simple.codegen;
+
+import com.seaofnodes.simple.Ary;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.print.IRPrinter;
+import com.seaofnodes.simple.type.*;
+import java.io.ByteArrayOutputStream;
+import java.util.*;
+
+
+/**
+ *  Instruction encodings
+ * <p>
+ *  This class holds the encoding bits, plus the relocation information needed
+ *  to move the code to a non-zero offset, or write to an external file (ELF).
+ * <p>
+ *  There are also a bunch of generic utilities for managing bits and bytes
+ *  common in all encodings.
+ */
+public class Encoding {
+
+    // Top-level program graph structure
+    public final CodeGen _code;
+
+    // Instruction bytes.  The registers are encoded already.  Relocatable data
+    // is in a fixed format depending on the kind of relocation.
+
+    // - RIP-relative offsets into the same chunk are just encoded with their
+    //   check relative offsets; no relocation info is required.
+
+    // - Fixed address targets in the same encoding will be correct for a zero
+    //   base; moving the entire encoding requires adding the new base address.
+
+    // - RIP-relative to external chunks have a zero offset; the matching
+    //   relocation info will be used to patch the correct value.
+
+    public static class BAOS extends ByteArrayOutputStream {
+        public byte[] buf() { return buf; }
+        void set( byte[] buf0, int count0 ) { buf=buf0; count=count0; }
+    };
+    final public BAOS _bits = new BAOS();
+
+    public int [] _opStart;     // Start  of opcodes, by _nid
+    public byte[] _opLen;       // Length of opcodes, by _nid
+
+    // Big Constant relocation info.
+    public static class Relo {
+        public final Node _op;
+        public final Type _t;          // Constant type
+        public final byte _off;        // Offset from start of opcode
+        public final byte _elf;        // ELF relocation type, e.g. 2/PC32
+        public int _target;      // Where constant is finally placede
+        public int _opStart;     // Opcode start
+        Relo( Node op, Type t, byte off, byte elf ) {
+            _op=op;  _t=t;  _off=off; _elf=elf;
+        }
+    }
+    public final HashMap<Node,Relo> _bigCons = new HashMap<>();
+
+    Encoding( CodeGen code ) { _code = code; }
+
+    // Shortcut to the defining register
+    public short reg(Node n) {
+        return _code._regAlloc.regnum(n);
+    }
+
+    public int read1(int idx) {
+        byte[] buf = _bits.buf();
+        return (buf[idx]&0xFF);
+    }
+    public int read2(int idx) {
+        byte[] buf = _bits.buf();
+        return (buf[idx]&0xFF) | (buf[idx+1]&0xFF) <<8;
+    }
+    public int read4(int idx) {
+        byte[] buf = _bits.buf();
+        return (buf[idx]&0xFF) | (buf[idx+1]&0xFF) <<8 | (buf[idx+2]&0xFF)<<16 | (buf[idx+3]&0xFF)<<24;
+    }
+    public long read8(int idx) {
+        return (read4(idx) & 0xFFFFFFFFL) | read4(idx+4);
+    }
+
+    // This buffer is invalid/moving until after all encodings are written
+    public byte[] bits() { return _bits.buf(); }
+
+    // 4 byte little-endian write
+    public void patch4( int idx, int val ) {
+        byte[] buf = _bits.buf();
+        buf[idx  ] = (byte)(val    );
+        buf[idx+1] = (byte)(val>> 8);
+        buf[idx+2] = (byte)(val>>16);
+        buf[idx+3] = (byte)(val>>24);
+    }
+
+    static void padN(int n, BAOS bits) {
+        while( (bits.size()+n-1 & -n) > bits.size() )
+            bits.write(0);
+    }
+
+    // Convenience for writing log-N
+    static void addN( int log, Type t, BAOS bits ) {
+        long x = t instanceof TypeInteger ti
+            ? ti.value()
+            : log==3
+            ? Double.doubleToRawLongBits(    ((TypeFloat)t).value())
+            : Float.floatToRawIntBits((float)((TypeFloat)t).value());
+        addN(log,x,bits);
+    }
+    static void addN( int log, long x, BAOS bits ) {
+        for( int i=0; i < 1<<log; i++ ) {
+            bits.write((int)x);
+            x >>= 8;
+        }
+    }
+
+    public Encoding add1( int op ) { addN(0,op,_bits); return this; }
+    public Encoding add2( int op ) { addN(1,op,_bits); return this; }
+    public Encoding add4( int op ) { addN(2,op,_bits); return this; }
+    public Encoding add8(long op ) { addN(3,op,_bits); return this; }
+
+
+    // Nodes need "relocation" patching; things done after code is placed.
+    // Record src and dst Nodes.
+    private final HashMap<Node,CFGNode> _internals = new HashMap<>();
+    // Source is a Call, destination in the Fun.
+    public Encoding relo( CallNode call ) {
+        _internals.put(call,_code.link(call.tfp()));
+        return this;
+    }
+    public Encoding relo( ConstantNode con ) {
+        TypeFunPtr tfp = (TypeFunPtr)con._con;
+        _internals.put(con,_code.link(tfp));
+        return this;
+    }
+    public void jump( CFGNode jmp, CFGNode dst ) {
+        _internals.put(jmp,dst.uctrlSkipEmpty());
+    }
+
+
+    final HashMap<Node,String> _externals = new HashMap<>();
+    public Encoding external( Node call, String extern ) {
+        _externals.put(call,extern);
+        return this;
+    }
+
+    // Store t as a 32/64 bit constant in the code space; generate RIP-relative
+    // addressing to load it
+    public void largeConstant( Node relo, Type t, int off, int elf ) {
+        assert t.isConstant();
+        assert (byte)off == off;
+        assert (byte)elf == elf;
+        _bigCons.put(relo,new Relo(relo,t,(byte)off,(byte)elf));
+    }
+
+    // --------------------------------------------------
+    void encode() {
+        // Basic block layout: negate branches to keep blocks in-order; insert
+        // unconditional jumps.  Attempt to keep backwards branches taken,
+        // forwards not-taken (this is the default prediction on most
+        // hardware).  Layout is still Reverse Post Order but with more
+        // restrictions.
+        basicBlockLayout();
+
+        // Write encoding bits in order into a big byte array.
+        // Record opcode start and length.
+        writeEncodings();
+
+        // Short-form RIP-relative support: replace long encodings with short
+        // encodings and compact the code, changing all the offsets.
+        compactShortForm();
+
+        // Patch RIP-relative and local encodings now.
+        patchLocalRelocations();
+    }
+
+    // --------------------------------------------------
+    // Basic block layout: negate branches to keep blocks in-order; insert
+    // unconditional jumps.  Attempt to keep backwards branches taken, forwards
+    // not-taken (this is the default prediction on most hardware).  Layout is
+    // still Reverse Post Order but with more restrictions.
+    private void basicBlockLayout() {
+        IdentityHashMap<LoopNode,Ary<CFGNode>> rpos = new IdentityHashMap<>();
+        Ary<CFGNode> rpo = new Ary<>(CFGNode.class);
+        rpos.put(_code._start.loop(),rpo);
+        BitSet visit = _code.visit();
+        //IdentityHashMap<CFGNode,LoopNode> looptail = new IdentityHashMap<>();
+        rpo.add(_code._stop);
+        for( Node n : _code._start._outputs )
+            if( n instanceof FunNode fun ) {
+                int x = rpo._len;
+                //_rpo_cfg2(fun, visit, rpo, looptail);
+                _rpo_cfg(fun, visit, rpos );
+                assert rpo.at(x) instanceof ReturnNode;
+            }
+        rpo.add(_code._start);
+
+        // Reverse in-place
+        for( int i=0; i< rpo.size()>>1; i++ )
+            rpo.swap(i,rpo.size()-1-i);
+        visit.clear();
+        _code._cfg = rpo;       // Save the new ordering
+    }
+
+
+    private void _rpo_cfg(CFGNode bb, BitSet visit, IdentityHashMap<LoopNode,Ary<CFGNode>> rpos ) {
+        if( bb==null || visit.get(bb._nid) ) return;
+        visit.set(bb._nid);
+        CFGNode next = bb.uctrl();
+
+        // Loops run an inner "rpo_cfg", then append the entire loop body in
+        // place.  This keeps loop bodies completely contained, although if
+        // Some Day Later we have real profile data we ought to arrange the
+        // branch orderings based on frequency.
+        if( bb instanceof LoopNode loop ) {
+            Ary<CFGNode> body = new Ary<>(CFGNode.class); // Private RPO for the loop
+            rpos.put(loop.loop(),body);                   // Find it via loop tree
+            _rpo_cfg(next,visit,rpos);                    // RPO the loop
+            body.add(loop);                               // Include loop last (first in RPO)
+            Ary<CFGNode> outer = rpos.get(loop.cfg(1).loop());
+            outer.addAll(body); // Append to original CFG
+            return;
+        }
+
+        // IfNodes visit 2 sides, and may choose to reorder them in the RPO
+        if( bb instanceof IfNode iff ) {
+            // Pick out the T/F projections
+            CProjNode t = iff.cproj(0);
+            CProjNode f = iff.cproj(1);
+            // Invert the branch or not
+            if( shouldInvert(t,f,iff.loopDepth()) ) {
+                iff.negate();
+                t.invert();
+                f.invert();
+                CProjNode tmp=f; f=t; t=tmp; // Swap t/f
+            }
+
+            // Whichever side is visited first becomes last in the RPO.  With
+            // no loops, visit the False side last (so True side first) so that
+            // when the False RPO visit returns, the IF is immediately next.
+            // When the RPO is reversed, the fall-through path will always be
+            // following the IF.
+            _rpo_cfg(t,visit,rpos); // True side first
+            next = f;               // False side last
+        }
+
+        // If the *next* BB has already been visited, and we are not already a
+        // jump, we may need an unconditional forwards jump here
+        Ary<CFGNode> rpo = rpos.get(bb.loop());
+        if( next!=null && visit.get(next._nid) && !(bb instanceof IfNode) ) {
+            boolean needJump = next instanceof LoopNode
+                // Empty blocks from an IF will invert the IF and backwards
+                // branch to the loop head.  If not empty, or not an IF
+                // will need a jump.
+                ? (bb.nOuts()>1 || !(bb.cfg0() instanceof IfNode) )
+                // Forwards jump.  If all the blocks, in RPO order, to our
+                // target are empty, we will fall in and not need a jump.
+                : !backwardsEmptyScan(rpo,next);
+            if( needJump ) {
+                CFGNode jmp = _code._mach.jump();
+                jmp._ltree = bb._ltree;
+                jmp.setDefX(0,bb);
+                next.setDef(next._inputs.find(bb),jmp);
+                rpo.add(jmp);
+            }
+        }
+
+        _rpo_cfg(next,visit,rpos);
+        rpo.add(bb);
+    }
+
+    // Should this test be inverted?
+    private static boolean shouldInvert(CFGNode t, CFGNode f, int bld) {
+        int tld = t.loopDepth(), fld = f.loopDepth();
+        // These next two are symmetric and can happen in any order; if `tld <
+        // bld` is true, the `fld < bld` must be false, or else both directions
+        // exit the loop... and the IF test would not be in the loop.
+
+        // true to exit a loop usually (and false falls into Yet Another Loop
+        // Block), invert if false is taking an empty backwards branch.
+        if( tld < bld ) return  forwardsEmptyScan(f,bld);
+        // false to exit a loop, normally invert to true (except empty back)
+        if( fld < bld ) return !forwardsEmptyScan(t,bld);
+
+        // Not exiting the loop; staying at this depth (or going deeper loop).
+
+        // Jump/true to an empty backwards block
+        if( forwardsEmptyScan(t,bld) ) return false;
+        if( forwardsEmptyScan(f,bld) ) return true ;
+
+        // Fall/false into a full block, Jump/true to an empty block.
+        if( f.nOuts()>1 && t.nOuts()==1 ) return false;
+        if( t.nOuts()>1 && f.nOuts()==1 ) return true ;
+        // Everything else equal, use pre-order
+        return t._pre > f._pre;
+    }
+
+    // Do we continue forwards from 'c' to the Loop back edge, without doing
+    // anything else?  Then this branch can directly jump to the loop head.
+    private static boolean forwardsEmptyScan( CFGNode c, int bld ) {
+        if( c.nOuts()!=1 || c.loopDepth()!=bld ) return false;
+        return c.uctrl() instanceof RegionNode cfg &&
+            (cfg instanceof LoopNode || forwardsEmptyScan(cfg,bld));
+    }
+
+    // Is the CFG from "next" to the end empty?  This means jumping to "next"
+    // will naturally fall into the end.
+    private static boolean backwardsEmptyScan(Ary<CFGNode> rpo, CFGNode next) {
+        for( int i=rpo._len-1; rpo.at(i)!=next; i-- )
+            if( rpo.at(i).nOuts()!=1 )
+                return false;
+        return true;
+    }
+
+    // --------------------------------------------------
+    // Write encoding bits in order into a big byte array.
+    // Record opcode start and length.
+    public FunNode _fun;        // Currently encoding function
+    private void writeEncodings() {
+        _opStart= new int [_code.UID()];
+        _opLen  = new byte[_code.UID()];
+        for( CFGNode bb : _code._cfg ) {
+            if( !(bb instanceof MachNode mach0) )
+                _opStart[bb._nid] = _bits.size();
+            else if( bb instanceof FunNode fun ) {
+                _fun = fun;     // Currently encoding function
+                _opStart[bb._nid] = _bits.size();
+                mach0.encoding( this );
+                _opLen[bb._nid] = (byte) (_bits.size() - _opStart[bb._nid]);
+            }
+            for( Node n : bb._outputs ) {
+                if( n instanceof MachNode mach && !(n instanceof FunNode) ) {
+                    _opStart[n._nid] = _bits.size();
+                    mach.encoding( this );
+                    _opLen[n._nid] = (byte) (_bits.size() - _opStart[n._nid]);
+                }
+            }
+        }
+    }
+
+    // --------------------------------------------------
+    // Short-form RIP-relative support: replace short encodings with long
+    // encodings and expand the code, changing all the offsets.
+    private void compactShortForm() {
+        int len = _code._cfg._len;
+        int[] oldStarts = new int[len];
+        for( int i=0; i<len; i++ )
+            oldStarts[i] = _opStart[_code._cfg.at(i)._nid];
+
+        // TODO: Rewrite this algo to use the small "_jmps" list of just the
+        // jumps instead of walking all blocks.
+        // TODO2: Allow short encodings on non-jumps.  This algo doesn't
+        // really care jumps vs other rip-relative things.
+
+        // Check the size of short jumps, adjust the block starts for a whole
+        // pass over all blocks.  If some jumps go long, they might stretch the
+        // distance for other jumps, so another pass is needed.
+        int slide = -1;
+        while( slide != 0) {    // While no fails
+            slide = 0;
+            for( int i=0; i<len; i++ ) {
+                CFGNode bb = _code._cfg.at(i);
+                // Functions pad to align 16
+                if( bb instanceof FunNode ) {
+                    int newStart = _opStart[bb._nid]+slide;
+                    slide += (newStart+15 & -16)-newStart;
+                }
+                _opStart[bb._nid] += slide;
+                // Slide down all other (non-CFG) ops in the block
+                for( Node n : bb._outputs )
+                    if( n instanceof MachNode && !(n instanceof CFGNode) )
+                        _opStart[n._nid] += slide;
+                if( bb instanceof RIPRelSize riprel ) {
+                    CFGNode target = (bb instanceof IfNode iff ? iff.cproj(0) : (CFGNode)bb.out(0)).uctrlSkipEmpty();
+                    // Delta is from opStart to opStart.  X86 at least counts
+                    // the delta from the opEnd, but we don't have the end until
+                    // we decide the size - so the encSize has to deal
+                    int delta = _opStart[target._nid] - _opStart[bb._nid];
+                    byte opLen = riprel.encSize(delta);
+                    // Recorded size is smaller than the current size?
+                    if( _opLen[bb._nid] < opLen ) {
+                        // Start sliding the code down; record slide amount and new size
+                        slide += opLen - _opLen[bb._nid];
+                        _opLen[bb._nid] = opLen;
+                    }
+                }
+            }
+        }
+
+
+        // Copy/slide the bits to make space for all the longer branches
+        int grow = _opStart[_code._cfg.at(len-1)._nid] - oldStarts[len-1];
+        if( grow > 0 ) {        // If no short-form ops, nothing to do here
+            int end = _bits.size();
+            byte[] bits = new byte[end+grow];
+            for( int i=len-1; i>=0; i-- ) {
+                int start = oldStarts[i];
+                if( start==0 && i>1 ) continue;
+                int oldStart = oldStarts[i];
+                int newStart = _opStart[_code._cfg.at(i)._nid];
+                System.arraycopy(_bits.buf(),oldStart,bits,newStart,end-start);
+                end = start;
+            }
+            _bits.set(bits,bits.length);
+        }
+    }
+
+
+    // --------------------------------------------------
+    // Patch local encodings now
+    void patchLocalRelocations() {
+        // Walk the local code-address relocations
+        for( Node src : _internals.keySet() ) {
+            int start  = _opStart[src._nid];
+            Node dst =  _internals.get(src);
+            int target = _opStart[dst._nid];
+            ((RIPRelSize)src).patch(this, start, _opLen[src._nid], target - start);
+        }
+    }
+
+    // --------------------------------------------------
+    // Write the constant pool into the BAOS and optionally patch locally
+    void writeConstantPool( BAOS bits, boolean patch ) {
+        padN(16,bits);
+
+        HashMap<Type,Integer> targets = new HashMap<>();
+
+        // By log size
+        for( int log = 3; log >= 0; log-- ) {
+            // Write the 8-byte constants
+            for( Node op : _bigCons.keySet() ) {
+                Relo relo = _bigCons.get(op);
+                if( relo._t.log_size()==log ) {
+                    // Map from relo to constant start and patch
+                    Integer target = targets.get(relo._t);
+                    if( target==null ) {
+                        targets.put(relo._t,target = bits.size());
+                        // Put constant into code space.
+                        if( relo._t instanceof TypeTuple tt ) // Constant tuples put all entries
+                            for( Type tx : tt._types )
+                                addN(log,tx,bits);
+                        else
+                            addN(log,relo._t,bits);
+                    }
+                    relo._target = target;
+                    relo._opStart= _opStart[op._nid];
+                    // Go ahead and locally patch in-memory
+                    if( patch )
+                        ((RIPRelSize)op).patch(this, relo._opStart, _opLen[op._nid], relo._target - relo._opStart);
+                }
+            }
+        }
+    }
+
+
+    // A series of libc/external calls that Simple can link against in a JIT.
+    // Since no runtime in the JVM process, using magic numbers for the CPU
+    // emulators to pick up on.
+    public static int SENTINAL_CALLOC = -4;
+
+    void patchGlobalRelocations() {
+        for( Node src : _externals.keySet() ) {
+            int start  = _opStart[src._nid];
+            String dst =  _externals.get(src);
+            int target = switch( dst ) {
+            case "calloc" -> SENTINAL_CALLOC;
+            default -> throw Utils.TODO();
+            };
+            ((RIPRelSize)src).patch(this, start, _opLen[src._nid], target - start);
+        }
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java b/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java
index 11c2b061..40f827ec 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java
@@ -24,7 +24,7 @@ public abstract class GlobalCodeMotion {
         schedEarly(code);
 
         // Break up shared global constants by functions
-        breakUpGlobalConstants(code);
+        breakUpGlobalConstants(code._start);
 
         code._visit.clear();
         schedLate (code);
@@ -45,23 +45,28 @@ public abstract class GlobalCodeMotion {
     }
 
     // Break up shared global constants by functions
-    private static void breakUpGlobalConstants( CodeGen code ) {
+    private static void breakUpGlobalConstants( Node start ) {
         // For all global constants
-        for( int i=0; i< code._start.nOuts(); i++ ) {
-            Node con = code._start.out(i);
+        for( int i=0; i< start.nOuts(); i++ ) {
+            Node con = start.out(i);
             if( con instanceof MachNode mach && mach.isClone() ) {
+                breakUpGlobalConstants(con);
                 // While constant has users in different functions
                 while( true ) {
                     // Find a function user, and another function
                     FunNode fun = null;
                     boolean done=true;
                     for( Node use : con.outs() ) {
-                        FunNode fun2 = use.cfg0().fun();
+                        FunNode fun2 = use instanceof ReturnNode ret ? ret.fun() : use.cfg0().fun();
                         if( fun==null || fun==fun2 ) fun=fun2;
                         else { done=false; break; }
                     }
                     // Single function user, so this constant is not shared
-                    if( done ) { i--; con.setDef(0,fun); break; }
+                    if( done ) {
+                        if( con.in(0)==start ) i--;
+                        con.setDef(0,fun);
+                        break;
+                    }
                     // Move function users to a private constant
                     Node con2 = mach.copy();  // Private constant clone
                     con2._inputs.set(0,null); // Preserve edge invariants from clone
@@ -155,13 +160,15 @@ public abstract class GlobalCodeMotion {
                         continue outer; // Nope, await all uses done
 
                 // Loads need their memory inputs' uses also done
-                if( n instanceof LoadNode ld )
+                if( n instanceof MemOpNode ld && ld._isLoad )
                     for( Node memuse : ld.mem()._outputs )
                         if( late[memuse._nid]==null &&
                             // New makes new memory, never crushes load memory
                             !(memuse instanceof NewNode) &&
                             // Load-use directly defines memory
                             (memuse._type instanceof TypeMem ||
+                             // Load-use directly defines memory
+                             memuse instanceof CallNode ||
                              // Load-use indirectly defines memory
                              (memuse._type instanceof TypeTuple tt && tt._types[ld._alias] instanceof TypeMem)) )
                             continue outer;
@@ -175,8 +182,8 @@ public abstract class GlobalCodeMotion {
                 if( def!=null && late[def._nid]==null ) {
                     work.push(def);
                     // if the def has a load use, maybe the load can fire
-                    for( Node ld : def._outputs )
-                        if( ld instanceof LoadNode && late[ld._nid]==null )
+                    for( Node out : def._outputs )
+                        if( out instanceof MemOpNode ld && ld._isLoad && late[ld._nid]==null )
                             work.push(ld);
                 }
         }
@@ -192,9 +199,36 @@ public abstract class GlobalCodeMotion {
               lca = use_block(n,use, late)._idom(lca,null);
 
         // Loads may need anti-dependencies, raising their LCA
-        if( n instanceof LoadNode load )
+        if( n instanceof MemOpNode load && load._isLoad )
             lca = find_anti_dep(lca,load,early,late);
 
+
+        // Nodes setting a single register and getting killed will stay close
+        // to the uses, since they will be forced to spill anyway.  The kill
+        // check is very weak, and some may be hoisted only to spill in the RA.
+        if( n instanceof MachNode mach ) {
+            RegMask out = mach.outregmap();
+            if( out!=null && out.size1() ) {
+                int reg = mach.outregmap().firstReg();
+                // Look for kills
+                outer:
+                for( CFGNode lca2=lca; lca2 != early; lca2 = lca2.idom() ) {
+                    if( lca2 instanceof MachNode mach2 ) {
+                        for( int i=1; i<lca2.nIns(); i++ ) {
+                            RegMask mask = mach2.regmap(i);
+                            if( mask!=null && mask.test(reg) ) {
+                                early = lca2 instanceof IfNode ? lca2.idom() : lca2;
+                                break outer;
+                            }
+                        }
+                        RegMask kill = mach2.killmap();
+                        if( kill != null )
+                            throw Utils.TODO();
+                    }
+                }
+            }
+        }
+
         // Walk up from the LCA to the early, looking for best place.  This is
         // the lowest execution frequency, approximated by least loop depth and
         // deepest control flow.
@@ -226,10 +260,12 @@ public abstract class GlobalCodeMotion {
     // Least loop depth first, then largest idepth
     private static boolean better( CFGNode lca, CFGNode best ) {
         return lca.loopDepth() < best.loopDepth() ||
-                (lca.idepth() > best.idepth() || best instanceof IfNode);
+            lca instanceof NeverNode ||
+            lca.idepth() > best.idepth() ||
+            best instanceof IfNode;
     }
 
-    private static CFGNode find_anti_dep(CFGNode lca, LoadNode load, CFGNode early, CFGNode[] late) {
+    private static CFGNode find_anti_dep(CFGNode lca, MemOpNode load, CFGNode early, CFGNode[] late) {
         // We could skip final-field loads here.
         // Walk LCA->early, flagging Load's block location choices
         for( CFGNode cfg=lca; early!=null && cfg!=early.idom(); cfg = cfg.idom() )
@@ -237,13 +273,15 @@ public abstract class GlobalCodeMotion {
         // Walk load->mem uses, looking for Stores causing an anti-dep
         for( Node mem : load.mem()._outputs ) {
             switch( mem ) {
-            case StoreNode st:
-                assert late[st._nid]!=null;
-                lca = anti_dep(load,late[st._nid],st.cfg0(),lca,st);
-                break;
-            case CallNode st:
-                assert late[st._nid]!=null;
-                lca = anti_dep(load,late[st._nid],st.cfg0(),lca,st);
+            case MemOpNode st:
+                if( !st._isLoad ) {
+                    assert late[mem._nid] != null;
+                    lca = anti_dep( load, late[mem._nid], mem.cfg0(), lca, st );
+                }
+                break; // Loads do not cause anti-deps on other loads
+            case CallNode call:
+                assert late[call._nid]!=null;
+                lca = anti_dep(load,late[call._nid],call.cfg0(),lca,call);
                 break;
             case PhiNode phi:
                 // Repeat anti-dep for matching Phi inputs.
@@ -253,7 +291,6 @@ public abstract class GlobalCodeMotion {
                         lca = anti_dep(load,phi.region().cfg(i),load.mem().cfg0(),lca,null);
                 break;
             case NewNode st: break;
-            case LoadNode ld: break; // Loads do not cause anti-deps on other loads
             case ReturnNode ret: break; // Load must already be ahead of Return
             case MemMergeNode ret: break; // Mem uses now on ScopeMin
             case NeverNode never: break;
@@ -264,16 +301,13 @@ public abstract class GlobalCodeMotion {
     }
 
     //
-    private static CFGNode anti_dep( LoadNode load, CFGNode stblk, CFGNode defblk, CFGNode lca, Node st ) {
-        // Walk store blocks "reach" from its scheduled location to its earliest
-        for( ; stblk != defblk.idom(); stblk = stblk.idom() ) {
-            // Store and Load overlap, need anti-dependence
-            if( stblk._anti==load._nid ) {
-                lca = stblk._idom(lca,null); // Raise Loads LCA
-                if( lca == stblk && st != null && st._inputs.find(load) == -1 ) // And if something moved,
-                    st.addDef(load);   // Add anti-dep as well
-                return lca;            // Cap this stores' anti-dep to here
-            }
+    private static CFGNode anti_dep( MemOpNode load, CFGNode stblk, CFGNode defblk, CFGNode lca, Node st ) {
+        // Store and Load overlap, need anti-dependence
+        if( stblk._anti==load._nid ) {
+            lca = stblk._idom(lca,null); // Raise Loads LCA
+            if( lca == stblk && st != null && st._inputs.find(load) == -1 ) // And if something moved,
+                st.addDef(load); // Add anti-dep as well
+            return lca;          // Cap this stores' anti-dep to here
         }
         return lca;
     }
diff --git a/src/main/java/com/seaofnodes/simple/codegen/IFG.java b/src/main/java/com/seaofnodes/simple/codegen/IFG.java
index 1f3186ff..fdd4e2f9 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/IFG.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/IFG.java
@@ -19,7 +19,7 @@ abstract public class IFG {
     static final IdentityHashMap<LRG,Node> TMP = new IdentityHashMap<>();
 
     // Inteference Graph: Array of Bitsets
-    private static final Ary<BitSet> IFG = new Ary<>(BitSet.class);
+    static final Ary<BitSet> IFG = new Ary<>(BitSet.class);
     static void resetIFG() {
         for( BitSet bs : IFG )
             if( bs!=null ) bs.clear();
@@ -79,6 +79,8 @@ abstract public class IFG {
         while( !WORK.isEmpty() )
             do_block(round,alloc,WORK.pop());
 
+        if( alloc.success() )
+            convert2DAdjacency(alloc);
         return alloc.success();
     }
 
@@ -125,18 +127,18 @@ abstract public class IFG {
             TMP.remove(lrg);    // Kill def
         }
 
+        // Phis use and define the same live range, i.e. these LRGs already
+        // marked conflicted, no need to mark again
         if( n instanceof PhiNode )
             return;
-        // A copy does not define a new value, and the src and dst can use the
-        // same register.  Remove the input from TMP/liveout set before
-        // interfering.
-        //if( n instanceof MachNode m && m.isSplit() )
-        //    TMP.remove(alloc.lrg(n.in(1))); // Kill spill-use
+
+        // Kill any killed registers; milli-code routines like New can kill
+        // will not being a CFG.
+        if( n instanceof MachNode m )
+            kills(alloc,m);
 
         // Interfere n with all live
         if( lrg!=null ) {
-            if( n instanceof MachNode m )
-                kills(alloc,m);
             // Interfere n with all live
             for( LRG tlrg : TMP.keySet() ) {
                 assert tlrg.leader();
@@ -148,9 +150,10 @@ abstract public class IFG {
                     // last tlrg register at some point, either tlrg or lrg
                     // must fail.  If *n* (a subset of lrg) needs the single
                     // last tlrg register then only tlrg must fail.
-                    if( lrg.size1() && !tlrg.clr(lrg._mask.firstReg()) )
-                        alloc.fail(tlrg);
-                    else addIFG(lrg,tlrg); // Add interference
+                    if( ((MachNode)n).outregmap().size1() ) {
+                        if( !tlrg.clr(lrg._mask.firstReg()) ) // Clear bit, no interference
+                            alloc.fail(tlrg);                 // Clearing drives mask to empty
+                    } else addIFG(lrg,tlrg); // Add interference
             }
         }
 
@@ -171,7 +174,7 @@ abstract public class IFG {
             // Look for a must-use single register conflicting with some other must-def.
             if( n instanceof MachNode m ) {
                 RegMask ni_mask = m.regmap(i);
-                if( ni_mask.size1() ) { // Must-use single register
+                if( ni_mask!=null && ni_mask.size1() ) { // Must-use single register
                     // Search all current live
                     for( LRG tlrg : TMP.keySet() ) {
                         assert tlrg.leader();
@@ -207,12 +210,17 @@ abstract public class IFG {
                 // Disallow clone-ables from killing registers.  Just fail
                 // them and re-clone closer to target... so no kill.
                 // Special case for Intel XOR used to zero.
-                if( m.isClone() )
+                Node n = (Node)m;
+                CFGNode effUseBlk = n.out(0) instanceof PhiNode phi ? phi.region().cfg(phi._inputs.find(n)) : n.out(0).cfg0();
+                if( m.isClone() &&  // Must be clonable
+                    (n.nOuts()>1 || // Has many users OR
+                     // Only 1 user but effective use is remote block
+                     effUseBlk != n.cfg0() ))
+                    // Then fail the clonable; it should split or move
                     alloc.fail(alloc.lrg((Node)m));
-                else if( !tlrg.sub(killMask) ) {
-                    tlrg._killed = true; // Failed by a kill-mask
+                // Else clonable cannot move
+                else if( !tlrg.sub(killMask) )
                     alloc.fail(tlrg);
-                }
             }
         }
     }
@@ -234,14 +242,12 @@ abstract public class IFG {
     private static void mergeLiveOut( RegAlloc alloc, CFGNode priorbb, int i ) {
         CFGNode bb = priorbb.cfg(i);
         if( bb == null ) return; // Start has no prior
-        if( !bb.blockHead() ) bb = bb.cfg0();
-        //if( i==0 && !(bb instanceof StartNode) ) bb = bb.cfg0();
-        assert bb.blockHead();
+        while( !bb.blockHead() ) bb = bb.cfg0();
 
         // Lazy get live-out set for bb
-      IdentityHashMap<LRG, Node> lrgs = BBOUTS.computeIfAbsent( bb, k -> new IdentityHashMap<>() );
+        IdentityHashMap<LRG, Node> lrgs = BBOUTS.computeIfAbsent( bb, k -> new IdentityHashMap<>() );
 
-      for( LRG lrg : TMP.keySet() ) {
+        for( LRG lrg : TMP.keySet() ) {
             Node def = TMP.get(lrg);
             // Effective def comes from phi input from prior block
             if( def instanceof PhiNode phi && phi.cfg0()==priorbb ) {
@@ -260,6 +266,24 @@ abstract public class IFG {
     }
 
 
+    static void convert2DAdjacency( RegAlloc alloc ) {
+        // Convert the 2-D array of bits (a 1-D array of BitSets) into an
+        // adjacency matrix.
+        int maxlrg = alloc._LRGS.length;
+        for( int i=1; i<maxlrg; i++ ) {
+            BitSet ifg = IFG.atX(i);
+            if( ifg != null ) {
+                LRG lrg0 = alloc._LRGS[i];
+                for( int lrg = ifg.nextSetBit(0); lrg>=0; lrg=ifg.nextSetBit(lrg+1) ) {
+                    LRG lrg1 = alloc._LRGS[lrg];
+                    lrg0.addNeighbor(lrg1);
+                    lrg1.addNeighbor(lrg0);
+                }
+            }
+        }
+    }
+
+
     // ------------------------------------------------------------------------
     // Color the inference graph.
 
@@ -276,22 +300,10 @@ abstract public class IFG {
     // If there's no spare color we'll have to spill this at-risk live range.
 
     public static boolean color(int round, RegAlloc alloc) {
-
-        // Convert the 2-D array of bits (a 1-D array of BitSets) into an
-        // adjacency matrix.
         int maxlrg = alloc._LRGS.length, nlrgs=0;
-        for( int i=1; i<maxlrg; i++ ) {
-            if( alloc._LRGS[i] != null ) nlrgs++;
-            BitSet ifg = IFG.atX(i);
-            if( ifg != null ) {
-                LRG lrg0 = alloc._LRGS[i];
-                for( int lrg = ifg.nextSetBit(0); lrg>=0; lrg=ifg.nextSetBit(lrg+1) ) {
-                    LRG lrg1 = alloc._LRGS[lrg];
-                    lrg0.addNeighbor(lrg1);
-                    lrg1.addNeighbor(lrg0);
-                }
-            }
-        }
+        for( int i=1; i<maxlrg; i++ )
+            if( alloc._LRGS[i] != null )
+                nlrgs++;
 
         // Simplify
 
@@ -407,7 +419,7 @@ abstract public class IFG {
         int best=sptr;
         int bestScore = pickRiskyScore(color_stack[best]);
         for( int i=sptr+1; i<color_stack.length; i++ ) {
-            if( bestScore == 999999 ) return best; // Already max score
+            if( bestScore == 1000000 ) return best; // Already max score
             int iScore = pickRiskyScore(color_stack[i]);
             if( iScore > bestScore )
                 { best = i; bestScore = iScore; }
@@ -424,13 +436,25 @@ abstract public class IFG {
     // Picking a live range that is very close to coloring might allow it to
     // color despite being risky.
     private static int pickRiskyScore( LRG lrg ) {
+        // Pick single-def clonables that are not right next to their single-use.
+        // Failing to color these will clone them closer to their uses.
+        if( !lrg._multiDef && lrg._machDef.isClone() ) {
+            Node def = ((Node)lrg._machDef);
+            Node use = ((Node)lrg._machUse);
+            CFGNode cfg = def.cfg0();
+            if( cfg != use.cfg0() || // Different blocks OR
+              // Same block, but not close
+              cfg._outputs.find(def) < cfg._outputs.find(use)+1 )
+                return 1000000;
+        }
+
         // Always pick callee-save registers as being very large area recovered
         // and very cheap to spill.
         if( lrg._machDef instanceof CalleeSaveNode )
-            return 999998;
-        if( lrg._splitDef != null && lrg._splitDef.in(1) instanceof CalleeSaveNode &&
+            return 1000000-2-lrg._mask.firstReg();
+        if( lrg._splitDef != null && lrg._splitDef. in(1) instanceof CalleeSaveNode &&
             lrg._splitUse != null && lrg._splitUse.out(0) instanceof ReturnNode )
-            return 999999;
+            return 1000000-1;
 
         // TODO: cost/benefit model.  Perhaps counting loop-depth (freq) of def/use for cost
         // and "area" for benefit
@@ -441,35 +465,39 @@ abstract public class IFG {
         if( mask.size1() ) return reg;
         // Check chain of splits up the def-chain.  Take first allocated
         // register, and if it's available in the mask, take it.
-        Node defSplit = lrg._splitDef, useSplit = lrg._splitUse;
-        int tidx, cnt=0;
+        Node def = lrg._splitDef, use = lrg._splitUse;
+        int tidx=0, cnt=0;
 
-        while( (tidx=biasable(defSplit)) != 0 || biasable(useSplit) != 0 ) {
+        while( def != null || use != null ) {
             if( cnt++ > 10 ) break;
 
-            if( tidx != 0 ) {
-                short bias = biasColor( alloc, defSplit, mask );
+            if( def != null ) {
+                short bias = biasColor( alloc, def, mask );
                 if( bias >= 0 ) return bias; // Good bias
-                if( bias == -2 ) defSplit = null; // Kill this side, no more searching
-            } else defSplit = null;
+                if( bias == -2 ) def = null; // Kill this side, no more searching
+                else if( (tidx=biasable(def)) == 0 ) def = null;
+            }
 
-            if( biasable(useSplit) != 0 ) {
-                short bias = biasColor( alloc, useSplit, mask );
+            if( use != null ) {
+                short bias = biasColor( alloc, use, mask );
                 if( bias >= 0 ) return bias; // Good bias
-                if( bias == -2 ) useSplit = null; // Kill this side, no more searching
-            } else useSplit = null;
+                if( bias == -2 ) use = null; // Kill this side, no more searching
+                else if( biasable(use)==0 ) use = null;
+            }
 
-            if( defSplit != null ) {
-                short bias = biasColorNeighbors( alloc, defSplit, mask );
+            if( def != null ) {
+                short bias = biasColorNeighbors( alloc, def, mask );
                 if( bias >= 0 ) return bias;
                 // Advance def side
-                defSplit = defSplit.in(tidx);
+                def = def.in(tidx);
+                if( alloc.lrg(def)==null ) def=null;
             }
 
-            if( useSplit != null ) {
-                short bias = biasColorNeighbors( alloc, useSplit, mask );
+            if( use != null ) {
+                short bias = biasColorNeighbors( alloc, use, mask );
                 if( bias >= 0 ) return bias;
-                useSplit = useSplit.out(0);
+                use = use.out(0);
+                if( biasable(use)==0 ) use=null;
             }
 
         }
@@ -478,7 +506,7 @@ abstract public class IFG {
 
     private static int biasable(Node split) {
         if( split instanceof SplitNode ) return 1; // Yes biasable, advance is slot 1
-        if( split instanceof PhiNode ) return 1;   // Yes biasable, advance is slot 1
+        if( split instanceof PhiNode phi ) return phi.region() instanceof LoopNode ? 2 : 1;   // Yes biasable, advance is slot 1
         if( !(split instanceof MachNode mach) ) return 0; // Not biasable
         return mach.twoAddress();                         // Only biasable if 2-addr
     }
@@ -503,7 +531,7 @@ abstract public class IFG {
 
         // Can I limit my own choices to valid neighbor choices?
         for( LRG alrg : slrg._adj ) {
-            int reg = alrg._reg;
+            short reg = alrg._reg;
             if( reg == -1 && alrg._mask.size1() )
                 reg = alrg._mask.firstReg();
             if( reg != -1 ) {
diff --git a/src/main/java/com/seaofnodes/simple/codegen/LRG.java b/src/main/java/com/seaofnodes/simple/codegen/LRG.java
index 394c4a01..ec254a2e 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/LRG.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/LRG.java
@@ -2,6 +2,7 @@ package com.seaofnodes.simple.codegen;
 
 import com.seaofnodes.simple.Ary;
 import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.Utils;
 import com.seaofnodes.simple.node.*;
 
 import java.util.IdentityHashMap;
@@ -37,16 +38,13 @@ public class LRG {
 
     // Count of single-register defs and uses
     short _1regDefCnt, _1regUseCnt;
+    // Count of all defs, uses.  Mostly interested 1 vs many
+    boolean _multiDef, _multiUse;
 
     // A sample MachNode def in the live range
     public MachNode _machDef, _machUse;
     short _uidx;                // _machUse input
 
-    // Mask set to empty via a kill-mask.  This is usually a capacity kill,
-    // which means we need to split and spill into memory - which means even if
-    // the def-side has many registers, it MUST spill.
-    boolean _killed;
-
     // Some splits used in biased coloring
     MachConcreteNode _splitDef, _splitUse;
 
@@ -59,6 +57,8 @@ public class LRG {
     // Adjacent Live Range neighbors.  Only valid during coloring
     Ary<LRG> _adj;
 
+    public int nadj() { return _adj==null ? 0 : _adj._len; }
+
     void addNeighbor(LRG lrg) {
         if( _adj==null ) _adj = new Ary<>(LRG.class);
         _adj.push(lrg);
@@ -77,7 +77,7 @@ public class LRG {
     }
 
     // More registers than neighbors
-    boolean lowDegree() { return (_adj==null ? 0 : _adj._len) < _mask.size(); }
+    boolean lowDegree() { return nadj() < _mask.size(); }
 
     LRG( short lrg ) { _lrg = lrg; _reg = -1; }
 
@@ -121,29 +121,39 @@ public class LRG {
         if( _machDef==null ) {
             _machDef = lrg._machDef;
         } else if( lrg._machDef!=null ) {
+            if( _machDef != lrg._machDef ) _multiDef=true;
             if( _1regDefCnt==0 )
                 _machDef = lrg._machDef;
             else if( _machDef==lrg._machDef )
                 _1regDefCnt--;
         }
         _1regDefCnt += lrg._1regDefCnt;
+        _multiDef |= lrg._multiDef;
 
         if( _machUse==null ) {
             _machUse = lrg._machUse;
+            _uidx = lrg._uidx;
         } else if( lrg._machUse!=null ) {
-            if( _1regUseCnt==0 )
+            if( _machUse != lrg._machUse ) _multiUse=true;
+            if( _1regUseCnt==0 ) {
                 _machUse = lrg._machUse;
+                _uidx = lrg._uidx;
+            }
             else if( _machUse==lrg._machUse )
                 _1regUseCnt--;
         }
         _1regUseCnt += lrg._1regUseCnt;
+        _multiUse |= lrg._multiUse;
 
         // Fold deepest Split
         _splitDef = deepSplit(_splitDef,lrg._splitDef);
         _splitUse = deepSplit(_splitUse,lrg._splitUse);
 
         // Fold together masks
-        _mask = _mask.and(lrg._mask);
+        RegMask mask = _mask.and(lrg._mask);
+        if( mask==null )
+            mask = _mask.copy().and(lrg._mask);
+        _mask = mask;
         return this;
     }
 
@@ -153,6 +163,8 @@ public class LRG {
 
     // Record any Mach def for spilling heuristics
     LRG machDef( MachNode def, boolean size1 ) {
+        if( _machDef!=null && _machDef!=def )
+            _multiDef = true;
         if( _machDef==null || size1 )
             _machDef = def;
         if( size1 )
@@ -164,6 +176,8 @@ public class LRG {
 
     // Record any Mach use for spilling heuristics
     LRG machUse( MachNode use, short uidx, boolean size1 ) {
+        if( _machUse!=null && _machUse!=use )
+            _multiUse = true;
         if( _machUse==null || size1 )
             { _machUse = use; _uidx = uidx; }
         if( size1 )
diff --git a/src/main/java/com/seaofnodes/simple/codegen/LinkMem.java b/src/main/java/com/seaofnodes/simple/codegen/LinkMem.java
new file mode 100644
index 00000000..e1e849e6
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/codegen/LinkMem.java
@@ -0,0 +1,23 @@
+package com.seaofnodes.simple.codegen;
+
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.node.Node;
+
+// In-memory linking
+public class LinkMem {
+    final CodeGen _code;
+    LinkMem( CodeGen code ) { _code = code; }
+
+    public CodeGen link() {
+        Encoding enc = _code._encoding;
+
+        // Patch external calls internally
+        enc.patchGlobalRelocations();
+
+        // Write any large constants into a constant pool; they
+        // are accessed by RIP-relative addressing.
+        enc.writeConstantPool(enc._bits,true);
+
+        return _code;
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/codegen/ListScheduler.java b/src/main/java/com/seaofnodes/simple/codegen/ListScheduler.java
index 1796ef7c..de4fadc4 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/ListScheduler.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/ListScheduler.java
@@ -48,6 +48,9 @@ public abstract class ListScheduler {
                     computeSingleRDef(bb,use);
             else
                 computeSingleRDef(bb,n);
+
+            if( n instanceof NewNode || n instanceof CallNode )
+                bb.fun()._hasCalls = true;
             return this;
         }
 
diff --git a/src/main/java/com/seaofnodes/simple/codegen/Machine.java b/src/main/java/com/seaofnodes/simple/codegen/Machine.java
index 13d7abc1..2766414f 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/Machine.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/Machine.java
@@ -1,22 +1,97 @@
 package com.seaofnodes.simple.codegen;
 
 import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.TypeFunPtr;
 
 abstract public class Machine {
     // Human readable machine name.  Something like "x86-64" or "arm" or "risc5"
     public abstract String name();
+    // Default opcode size for printing; 4 bytes for most 32-bit risc chips
+    public int defaultOpSize() { return 4; }
     // Human-readable name for a register number, e.g. "RAX" or "R0"
-    public abstract String reg( int reg );
+    public abstract String[] regs();
     // Create a split op; any register to any register, including stack slots
     public abstract SplitNode split( String kind, byte round, LRG lrg);
-    // List of caller-save registers
-    public abstract RegMask callerSave();
-    // List of callee-save registers
-    public abstract RegMask calleeSave();
+    // List of caller-save registers, as a 64bit mask
+    public abstract long callerSave();
+    // List of never-save registers, e.g. RSP or a ZERO register if you have one
+    public abstract long neverSave();
+    // Call Argument Mask.  Passed in the function signature and argument
+    // number (2-based; 0 is for control and 1 for memory).  Also passed in a 0
+    // for the function itself, or for *outgoing* calls, the maximum stack slot
+    // given to the incoming function arguments (stack slots reserved for
+    // incoming arguments).
+    public abstract RegMask callArgMask(TypeFunPtr tfp, int arg, int maxArgSlot);
+    // Return register mask, based on signature (GPR vs FPR)
+    public abstract RegMask retMask(TypeFunPtr tfp);
+    // Return PC register
+    public abstract int rpc();
     // Return a MachNode unconditional branch
     public abstract CFGNode jump();
-    // Break an infinite loop
-    public abstract IfNode never( CFGNode ctrl );
     // Instruction select from ideal nodes
     public abstract Node instSelect( Node n );
+
+    /** Stack Slot Numbering
+
+RA gives all registers a number, starting at 0.  Stack slots continue this
+numbering going up from the last register number.  Common register numbers are
+0-15 for GPRs, 16-31 for FPRs, 32 for flags, and stack slots starting at
+register#33 going up.  These numbers are machine-specific, YMMV, etc; e.g. RPC
+is only in stack slot 0 on X86; other cpus start with the rpc in a register
+which may spill into any generic spill slot.
+
+For ease of reading and printing, stack slots start again at slot#0 - but
+during RA they are actually biased by CPU.MAX_REG.
+
+Stack Layout during Reg Alloc:
+
+         Slot  Value    Description
+        ----  -------  -----------
+MAXREG+ R+1   argR     maxArgSlot(calleR tfp), can be 0
+        ...
+MAXREG+ 1     arg0
+        ----  -- Caller ------
+MAXREG+ 0     RPC
+MAXREG+ R+E+N PAD      optional alignment
+
+MAXREG+  +    Spills   Caller Frame Space; N spills
+MAXREG+ R+E+1 Spills
+
+MAXREG+ R+E   argE     maxArgSlot(calleE tfp), can be 0
+        ...
+MAXREG+ R+2   arg0
+        ----  -- Callee -------
+        ...
+
+Slots defined by maxArgSlot do not have to contain the actual passed argument;
+they can be "shadow slots".  If they exist, they are property of the frame /
+FunNode where the TFP comes from.
+
+For a given calleR, there are generally many calleE's and they all share the
+low-range stack slots.
+
+Example:, Win64, main(int arg) { calloc(1,size); }
+
+                           Post-Warp: SP+56   shadow-main-arg
+Pre-alloc               Post-Alloc    SP+48   RPC
+--- -------             ----------    -------------
+40  spill#3             SP+40         SP+40   spill#3
+39  spill#2             SP+32          ""
+38  spill#1             SP+24          ""
+37  spill#0             SP+16          ""     spill#0
+36  shadow-calloc#size  SP+ 8         SP+ 8   shadow-calloc#size
+35  shadow-calloc#1     SP+ 0         SP+ 0   shadow-calloc#1
+--- --- FRAME BASE ----------         ---- FRAME BASE -------
+34  shadow-main-arg     SP+56
+33  RPC                 SP+48
+
+
+    */
+
+
+    // Maximum stack slot (or 0) for the args in this TFP.  This will include
+    // shadow slots if defined in the ABI, even if all arguments are passed in
+    // registers.
+    public abstract short maxArgSlot(TypeFunPtr tfp);
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/codegen/RIPRelSize.java b/src/main/java/com/seaofnodes/simple/codegen/RIPRelSize.java
new file mode 100644
index 00000000..777182dc
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/codegen/RIPRelSize.java
@@ -0,0 +1,14 @@
+package com.seaofnodes.simple.codegen;
+
+// This Node rip-relative encodings has sizes that vary by delta
+public interface RIPRelSize {
+    // delta is the distance from the opcode *start* to the target start.  Each
+    // hardware target adjusts as needed, X86 measures from the opcode *end*
+    // and small jumps are 2 bytes, so they'll need to subtract 2.
+    byte encSize(int delta);
+
+    // Patch full encoding in.  Used for both short and long forms.  delta
+    // again is from the opcode *start*.
+    void patch( Encoding enc, int opStart, int opLen, int delta );
+
+}
diff --git a/src/main/java/com/seaofnodes/simple/codegen/RegAlloc.java b/src/main/java/com/seaofnodes/simple/codegen/RegAlloc.java
index badec740..bd4cbf35 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/RegAlloc.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/RegAlloc.java
@@ -4,6 +4,7 @@ import com.seaofnodes.simple.Ary;
 import com.seaofnodes.simple.Utils;
 import com.seaofnodes.simple.node.*;
 import java.util.Arrays;
+import java.util.BitSet;
 import java.util.IdentityHashMap;
 
 /**
@@ -129,11 +130,18 @@ public class RegAlloc {
     }
 
     // Printable register number for node n
-    String reg( Node n ) {
+    String reg( Node n ) { return reg(n,null); }
+    String reg( Node n, FunNode fun ) {
         LRG lrg = lrg(n);
         if( lrg==null ) return null;
+        // No register yet, use LRG
         if( lrg._reg == -1 ) return "V"+lrg._lrg;
-        return _code._mach.reg(lrg._reg);
+        // Chosen machine register unless stack-slot and past RA
+        String[] regs = _code._mach.regs();
+        if( lrg._reg < regs.length || _code._phase.ordinal() <= CodeGen.Phase.RegAlloc.ordinal() || fun==null )
+            return RegMask.reg(regs,lrg._reg);
+        // Stack-slot past RA uses the frame layout logic
+        return "[rsp+"+fun.computeStackOffset(_code,lrg._reg)+"]";
     }
 
     // -----------------------
@@ -141,15 +149,31 @@ public class RegAlloc {
 
     public void regAlloc() {
         // Insert callee-save registers
+        String[] regs = _code._mach.regs();
+        long neverSave= _code._mach.neverSave();
         for( CFGNode bb : _code._cfg )
-            if( bb instanceof FunNode fun )
-                insertCalleeSave(fun);
+            if( bb instanceof FunNode fun ) {
+                ReturnNode ret = fun.ret();
+                int len = Math.min(regs.length,64);
+                for( int reg=0; reg<len; reg++ )
+                    if( !_code._callerSave.test(reg) && ((1L<<reg)&neverSave)==0 ) {
+                        ret.addDef(new CalleeSaveNode(fun,reg,regs[reg]));
+                        assert ret.regmap(ret.nIns()-1).firstReg()==reg;
+                    }
+            }
+        // Cache reg masks for New and Call
+        for( CFGNode bb : _code._cfg ) {
+            if( bb instanceof CallEndNode cend ) cend.cacheRegs(_code);
+            for( Node n : bb._outputs )
+                if( n instanceof NewNode nnn ) nnn.cacheRegs(_code);
+        }
 
         // Top driver: repeated rounds of coloring and splitting.
         byte round=0;
         while( !graphColor(round) ) {
             split(round);
-            assert round < 7; // Really expect to be done soon
+            if( round >= 7 )    // Really expect to be done soon
+                throw Utils.TODO("Allocator taking too long");
             round++;
         }
         postColor();                       // Remove no-op spills
@@ -166,24 +190,12 @@ public class RegAlloc {
             BuildLRG.run(round,this) && // if no hard register conflicts
             // Build Interference Graph
             IFG.build(round,this) &&    // If no self conflicts or uncolorable
+            // Conservative coalesce copies
+            Coalesce.coalesce(round,this) &&
             // Color attempt
             IFG.color(round,this);      // If colorable
     }
 
-    // Insert callee-save registers.  Walk the callee-save RegMask ignoring any
-    // Parms, then insert a Parm and an edge from the Ret to the Parm with the
-    // callee-save register.
-    private void insertCalleeSave( FunNode fun ) {
-        RegMask saves = _code._mach.calleeSave();
-        ReturnNode ret = fun.ret();
-
-        for( short reg = saves.firstReg(); reg != -1; reg = saves.nextReg(reg) ) {
-            ret.addDef(new CalleeSaveNode(fun,reg,_code._mach.reg(reg)));
-            assert ((MachNode)ret).regmap(ret.nIns()-1).firstReg()==reg;
-        }
-    }
-
-
     // -----------------------
     // Split conflicted live ranges.
     void split(byte round) {
@@ -193,11 +205,15 @@ public class RegAlloc {
         // independently... which generally requires a full pass over the
         // program for each failing live range.  i.e., might be a lot of
         // passes.
-        for( LRG lrg : _failed.keySet() )
+
+        // Sort, to avoid non-deterministic HashMap ordering
+        LRG[] splits = _failed.keySet().toArray(new LRG[0]);
+        Arrays.sort(splits, (x,y) -> x._lrg - y._lrg );
+        for( LRG lrg : splits )
             split(round,lrg);
     }
 
-    // Split this live range
+    // Split this live range, top level heuristic
     boolean split( byte round, LRG lrg ) {
         assert lrg.leader();  // Already rolled up
 
@@ -206,13 +222,16 @@ public class RegAlloc {
 
         // Register mask when empty; split around defs and uses with limited
         // register masks.
-        if( lrg._mask.isEmpty() ) {
+        if( lrg._mask.isEmpty() && (!lrg._multiDef || lrg._1regUseCnt==1) ) {
             if( lrg._1regDefCnt <= 1 &&
                 lrg._1regUseCnt <= 1 &&
                 (lrg._1regDefCnt + lrg._1regUseCnt) > 0 )
                 return splitEmptyMaskSimple(round,lrg);
-            // Default to splitByLoop
-            //return splitEmptyMask(round,lrg);
+            // Repeated single-reg uses from a single def.  Special for archs
+            // with more fixed regs.
+            if( !lrg._multiDef && lrg._1regDefCnt <= 1 && lrg._1regUseCnt > 2 )
+                if( splitEmptyMaskByUse(round,lrg) )
+                    return true;
         }
 
         // Generic split-by-loop depth.
@@ -235,39 +254,80 @@ public class RegAlloc {
             //   alloc
             //     V2/rax - kills prior RAX
             //   st4 [V1],len - No good, must split around
-            makeSplit("def/empty1",round,lrg).insertAfter((Node)lrg._machDef, false/*true*/);
+            insertAfterAndReplace( makeSplit("def/empty1",round,lrg), (Node)lrg._machDef, false/*true*/);
         // Split just before use
-        if( lrg._1regUseCnt==1 )
+        if( lrg._1regUseCnt==1 || (lrg._1regDefCnt==1 && ((Node)lrg._machDef).nOuts()==1) )
             insertBefore((Node)lrg._machUse,lrg._uidx,"use/empty1",round,lrg);
         return true;
     }
 
-    // Split live range with an empty mask.  Specifically forces splits at
-    // single-register defs or uses everywhere.
-    boolean splitEmptyMask( byte round, LRG lrg ) {
-        findAllLRG(lrg);
-        // If no single-use or single-def, assume this is a complete register
-        // kill and force spilling everywhere.
-        boolean all = lrg._killed || (lrg._1regDefCnt + lrg._1regUseCnt)==0;
-        for( Node n : _ns ) {
-            if( !(n instanceof MachNode mach) ) continue;
-            // Find def of spilling live range; spilling everywhere, OR
-            // single-register DEF and not cloneable (since these will clone
-            // before every use)
-            if( lrg(n)==lrg && (all || (!mach.isClone() && mach.outregmap().size1() )) )
-                makeSplit(n,"def/empty2",round,lrg).insertAfter(n,true);
-            // Find all uses
-            for( int i=1; i<n.nIns(); i++ ) {
-                Node def = n.in(i);
-                // Skip any new splits inserted just this pass
-                while( def instanceof SplitNode && lrg(def)==null )
-                    def = def.in(1);
-                // Main def (past splits) is of the spilling lrg, and spilling
-                // single-register USE (or everywhere)
-                if( lrg(def)==lrg && (all || mach.regmap(i).size1()) )
-                    insertBefore(n,i,"use/empty2",round,lrg);
+    // Single-def live range with an empty mask.  There are many single-reg
+    // uses.  Theory is there's many repeats of the same reg amongst the uses.
+    // In of splitting once per use, start by splitting into groups based on
+    // required input register.
+    boolean splitEmptyMaskByUse( byte round, LRG lrg ) {
+        Node def = (Node)lrg._machDef;
+
+        // Look at each use, and break into non-overlapping register classes.
+        Ary<RegMask> rclass = new Ary<>(RegMask.class);
+        boolean done=false;
+        int ncalls=0;
+        while( !done ) {
+            done = true;
+            for( Node use : def._outputs )
+                if( use instanceof MachNode mach ) {
+                    if( mach instanceof CallNode ) ncalls++;
+                    for( int i=1; i<use.nIns(); i++ )
+                        if( use.in(i)==def )
+                            done = putIntoRegClass( rclass, mach.regmap(i) );
+                }
+        }
+
+        // See how many register classes we split into.  Generally not
+        // productive to split like this across calls, which are going to kill
+        // all registers anyways.
+        if( rclass._len <= 1 || ncalls > 1 ) return false;
+
+        // Split by class
+        Ary<Node> ns = new Ary<>(Node.class);
+        for( RegMask rmask : rclass ) {
+            ns.addAll(def._outputs);
+            Node split = makeSplit(def,"popular",round,lrg);
+            split.insertAfter( def );
+            if( split.nIns()>1 ) split.setDef(1,def);
+            // all uses by class to split
+            for( Node use : ns ) {
+                if( use instanceof MachNode mach && use!=split ) {
+                    // Check all use inputs for n, in case there's several
+                    for( int i = 1; i < use.nIns(); i++ )
+                        // Find a def input, and check register class
+                        if( use.in( i ) == def ) {
+                            RegMask m = mach.regmap( i );
+                            if( m!=null && mach.regmap( i ).overlap( rmask ) )
+                                // Modify use to use the split version specialized to this rclass
+                                use.setDefOrdered( i, split );
+                        }
+                }
+            }
+            ns.clear();
+        }
+        return true;
+    }
+
+
+    // Put use into a register class, perhaps adding a class or perhaps
+    // narrowing a class (and causing a repeat)
+    private static boolean putIntoRegClass( Ary<RegMask> rclass, RegMask rmask ) {
+        for( int i=0; i<rclass._len; i++ ) {
+            RegMask omask = rclass.at(i);
+            if( omask.and(rmask) == omask ) return true; // Within the same register class
+            if( omask.overlap(rmask) ) {
+                rclass.set(i,new RegMask(omask.copy().and(rmask)));
+                return false;   // Need go again
             }
         }
+        // Add a new class, no need to go again
+        rclass.push(rmask);
         return true;
     }
 
@@ -281,27 +341,28 @@ public class RegAlloc {
         // For all conflicts
         for( Node def : conflicts ) {
             assert lrg(def)==lrg; // Might be conflict use-side
+            // Split before each use that extends the live range; i.e. is a
+            // Phi or two-address
+            for( int i=0; i<def._outputs._len; i++ ) {
+                Node use = def.out(i);
+                if( (use instanceof PhiNode phi &&
+                     !(phi.region() instanceof LoopNode loop && phi.in(2)==def && def.cfg0().idepth() > loop.idepth() ) ) ||
+                        (use instanceof MachNode mach && mach.twoAddress()!=0 && use.in(mach.twoAddress())==def) )
+                    insertBefore( use, use._inputs.find(def), "use/self/use",round,lrg );
+            }
             // Split after the Phi which extends the LRG.  Split also before
             // Phi slot 1 (and not all inputs), because Phis extend the live range.
             // TODO: split before all inputs (except the last; at least 1 split here must be extra)
             if( def instanceof PhiNode phi && !(def instanceof ParmNode) ) {
                 SplitNode split = makeSplit("def/self",round,lrg);
-                split.insertAfter(def,false);
+                insertAfterAndReplace(split,def,false);
                 if( split.nOuts()==0 )
-                    split.kill();
+                    split.killOrdered();
                 insertBefore(phi,1,"use/self/phi",round,lrg);
             }
             // Split before two-address ops which extend the live range
             if( def instanceof MachNode mach && mach.twoAddress()!= 0 )
                 insertBefore(def,mach.twoAddress(),"use/self/two",round,lrg);
-            // Split before each use that extends the live range; i.e. is a
-            // Phi or two-address
-            for( int i=0; i<def._outputs._len; i++ ) {
-                Node use = def.out(i);
-                if( (use instanceof PhiNode phi && !(phi.region() instanceof LoopNode && phi.in(2)==def ) ) ||
-                        (use instanceof MachNode mach && mach.twoAddress()!=0 && use.in(mach.twoAddress())==def) )
-                    insertBefore( use, use._inputs.find(def), "use/self/use",round,lrg );
-            }
         }
         return true;
     }
@@ -348,10 +409,10 @@ public class RegAlloc {
                 (min==max || n.cfg0().loopDepth() <= min) ) {
                 // Cloneable constants will be cloned at uses, not after def
                 if( !(n instanceof MachNode mach && mach.isClone()) &&
-                    // Single user is already a split
-                    !(n.nOuts()==1 && n.out(0) instanceof SplitNode) )
+                    // Single user is already a split adjacent
+                    !(n.nOuts()==1 && n.out(0) instanceof SplitNode split && sameBlockNoClobber(split) ) )
                     // Split after def in min loop nest
-                    makeSplit("def/loop",round,lrg).insertAfter(n,false);
+                    insertAfterAndReplace( makeSplit("def/loop",round,lrg), n,true);
             }
 
             // PhiNodes check all CFG inputs
@@ -362,20 +423,19 @@ public class RegAlloc {
                         // splitting in inner loop or at loop border
                         (min==max || phi.region().cfg(i).loopDepth() <= min) &&
                         // and not around the backedge of a loop (bad place to force a split, hard to remove)
-                        !(phi.region() instanceof LoopNode && i==2) )
+                        !(phi.region() instanceof LoopNode && i==2 && (phi.in(i) instanceof PhiNode pp && pp.region()==phi.region())) )
                         // Split before phi-use in prior block
                         insertBefore(phi,i, "use/loop/phi",round,lrg);
 
             } else {
                 // Others check uses
                 for( int i=1; i<n.nIns(); i++ ) {
-                    if( lrgSame(n.in(i),lrg) && // This is a LRG use
-                        // splitting in inner loop or at loop border
-                        (min==max || n.cfg0().loopDepth() <= min) &&
-                        // Not a single-use split same block already
-                        !(n.in(i) instanceof SplitNode && n.in(i).nOuts()==1 && n.cfg0()==n.in(i).cfg0()) )
+                    // This is a LRG use
+                    // splitting in inner loop or at loop border
+                    if( lrgSame( n.in( i ), lrg ) &&
+                        (min == max || (n.in(i) instanceof MachNode mach && mach.isClone()) || n.cfg0().loopDepth() <= min) )
                         // Split before in this block
-                        insertBefore( n, i, "use/loop/use", round,lrg );
+                        insertBefore( n, i, "use/loop/use", round,lrg, false );
                 }
             }
         }
@@ -396,6 +456,22 @@ public class RegAlloc {
         int min = (int)ld;
         int max = (int)(ld>>32);
         int d = cfg.loopDepth();
+        // if n will lower the min loop and is in the tail end of the loop
+        // header, splitting "around" the loop will not help.  Treat n as being
+        // in the loop.
+        if( d < min ) {
+            if( cfg.uctrl() instanceof LoopNode loop && loop.entry()==cfg ) {
+                for( int i=cfg.nOuts()-2; i>=0; i-- ) {
+                    Node out = cfg.out(i);
+                    if( n==out )
+                        { d = loop.loopDepth(); break; } // Treat n as being "in the loop"
+                    if( !((out instanceof MachNode mach && mach.isClone()) || out instanceof SplitNode ) )
+                        break;  // Treat b as "normal", out of loop
+                }
+            }
+        }
+
+        // lower min, raise max, and re-fold
         min = Math.min(min,d);
         max = Math.max(max,d);
         return ((long)max<<32) | min;
@@ -421,12 +497,12 @@ public class RegAlloc {
         for( Node n : _ns ) assert !n.isDead();
     }
 
-    void insertBefore(Node n, int i, String kind, byte round, LRG lrg) {
+    void insertBefore(Node n, int i, String kind, byte round, LRG lrg, boolean skip) {
         Node def = n.in(i);
         // Effective block for use
         CFGNode cfg = n instanceof PhiNode phi ? phi.region().cfg(i) : n.cfg0();
         // Def is a split ?
-        if( def instanceof SplitNode ) {
+        if( skip && def instanceof SplitNode ) {
             boolean singleReg = n instanceof MachNode mach && mach.regmap(i).size1();
             // Same block, multiple registers, split is only used by n,
             // assume this is good enough and do not split again.
@@ -435,9 +511,30 @@ public class RegAlloc {
         }
         makeSplit(def,kind,round,lrg).insertBefore(n, i);
         // Skip split-of-split same block
-        if( def instanceof SplitNode && cfg==def.cfg0() )
+        if( skip && def instanceof SplitNode && cfg==def.cfg0() )
             n.in(i).setDefOrdered(1,def.in(1));
     }
+    void insertBefore(Node n, int i, String kind, byte round, LRG lrg) {
+        insertBefore(n,i,kind,round,lrg,true);
+    }
+
+    // Replace uses of `def` with `split`, and insert `split` immediately after
+    // `def` in the basic block.
+    public void insertAfterAndReplace( Node split, Node def, boolean must ) {
+        split.insertAfter(def);
+        if( split.nIns()>1 ) split.setDef(1,def);
+        for( int j=def.nOuts()-1; j>=0; j-- ) {
+            Node use = def.out(j);
+            if( use==split ) continue; // Skip self
+            // Can we avoid a split of a split?  'this' split is used by
+            // another split in the same block.
+            if( !must && use instanceof SplitNode split2 && sameBlockNoClobber(split2) )
+                continue;
+            int idx = use._inputs.find(def);
+            use.setDefOrdered(idx,split);
+            if( j < def.nOuts() ) j++;
+        }
+    }
 
     private Node makeSplit( Node def, String kind, byte round, LRG lrg ) {
         Node split = def instanceof MachNode mach && mach.isClone()
@@ -456,11 +553,27 @@ public class RegAlloc {
     // -----------------------
     // POST PASS: Remove empty spills that biased-coloring made
     private void postColor() {
+        int maxReg = -1;
         for( CFGNode bb : _code._cfg ) { // For all ops
+            if( bb instanceof FunNode fun )
+                maxReg = -1;   // Reset for new function
+            // Compute frame size, based on arguments and largest reg seen
+            if( bb instanceof ReturnNode ret )
+                ret.fun().computeFrameAdjust(_code,maxReg);
+            // Raise frame size by max stack args passed, even if ignored
+            if( bb instanceof CallEndNode cend )
+                maxReg = Math.max(maxReg,cend._xslot);
+
             for( int j=0; j<bb.nOuts(); j++ ) {
                 Node n = bb.out(j);
-                if( !(n instanceof SplitNode lo) ) continue;
-                int defreg = lrg(n      )._reg;
+                if( lrg(n)!=null )
+                    maxReg = Math.max(maxReg,lrg(n)._reg+1);
+                // Raise frame size by max stack args passed to New
+                if( n instanceof NewNode nnn )
+                    maxReg = Math.max(maxReg,nnn._xslot);
+
+                if( !(n instanceof SplitNode ) ) continue;
+                int defreg = lrg(n     )._reg;
                 int usereg = lrg(n.in(1))._reg;
                 // Attempt to bypass split
                 if( defreg != usereg && splitBypass(bb,j,n,defreg) )
@@ -499,4 +612,24 @@ public class RegAlloc {
         lo.setDefOrdered(1,hi.in(1));
         return true;
     }
+
+
+    public boolean sameBlockNoClobber( SplitNode split ) {
+        Node def = split.in(1);
+        CFGNode cfg = def.cfg0();
+        if( cfg != split.cfg0() ) return false; // Not same block
+        // Get multinode head
+        Node def0 = def instanceof ProjNode ? def.in(0) : def;
+        int defreg = lrg(def)._reg;
+        if( defreg == -1 ) defreg = lrg(def)._mask.firstReg();
+        if( defreg == -1 ) return false; // no allowed registers -> clobbered
+        for( int idx = cfg._outputs.find(split) -1; idx >= 0; idx-- ) {
+            Node n = cfg.out(idx);
+            if( n==def0 ) return true;    // No clobbers
+            if( lrg(n) == lrg(def) ) return false; // Self conflict
+            if( lrg(n)!=null && lrg(n)._reg == defreg )
+                return false;   // Clobbered
+        }
+        throw Utils.TODO();
+    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/codegen/RegMask.java b/src/main/java/com/seaofnodes/simple/codegen/RegMask.java
index f28805b5..ec0c4e30 100644
--- a/src/main/java/com/seaofnodes/simple/codegen/RegMask.java
+++ b/src/main/java/com/seaofnodes/simple/codegen/RegMask.java
@@ -4,11 +4,11 @@ import com.seaofnodes.simple.Utils;
 import com.seaofnodes.simple.SB;
 
 /** RegMask
- *  A "register mask" - 1 bit set for each allowed register.  In addition
+ *  A "register mask" - 1 bit set for each allowed register.  In addition,
  *  "stack slot" registers may be allowed, effectively making the set infinite.
  * <p>
  *  For smaller and simpler machines it suffices to make such masks an i64 or
- *  i128 (64 or 128 bit integers), and this presentation is by far the better
+ *  i128 (64- or 128-bit integers), and this presentation is by far the better
  *  way to go... if all register allocations can fit in this bit limitation.
  *  The allocator will need bits for stack-based parameters and for splits
  *  which cannot get a register.  For a 32-register machine like the X86, add 1
@@ -28,10 +28,11 @@ public class RegMask {
 
     public RegMask(int bit) {
         if( bit < 64 ) _bits0 = 1L<<bit;
-        else _bits1 = 1L<<(bit=64);
+        else _bits1 = 1L<<(bit-64);
     }
     public RegMask(long bits ) { _bits0 = bits; }
     public RegMask(long bits0, long bits1 ) { _bits0 = bits0; _bits1 = bits1; }
+    public RegMask(RegMask r) { _bits0 = r._bits0; _bits1 = r._bits1; }
     private RegMask() { _bits0 = _bits1 = 0; }
 
     // AND, with copy-on-write if changing
@@ -65,6 +66,7 @@ public class RegMask {
 
 
     public short firstReg() {
+        if( isEmpty() ) return -1;
         return (short)(_bits0 != 0
                        ? Long.numberOfTrailingZeros(_bits0)
                        : Long.numberOfTrailingZeros(_bits1)+64);
@@ -84,7 +86,7 @@ public class RegMask {
 
     boolean isEmpty() { return _bits0==0 && _bits1==0; }
 
-    boolean test( int reg ) {
+    public boolean test( int reg ) {
         return ((reg<64 ? (_bits0 >> reg) : (_bits1 >> (reg-64))) & 1)  != 0;
     }
 
@@ -108,35 +110,17 @@ public class RegMask {
         Machine mach = CodeGen.CODE._mach;
         if( _bits0==0 && _bits1==0 ) return sb.p("[]");
         sb.p("[");
+        String[] regs = mach.regs();
         for( int i=0; i<64; i++ )
             if( ((_bits0 >> i)&1) != 0 )
-                sb.p(mach.reg(i)).p(",");
+                sb.p(reg(regs,i)).p(",");
         for( int i=0; i<64; i++ )
             if( ((_bits1 >> i)&1) != 0 )
-                sb.p(mach.reg(i+64)).p(",");
+                sb.p(reg(regs,i+64)).p(",");
         return sb.unchar().p("]");
     }
-}
 
-// Mutable regmask(writable)
-class RegMaskRW extends RegMask {
-    public RegMaskRW(long x, long y) { super(x,y);  }
-    // clears bit at position r. Returns true if the mask is still not empty.
-    public boolean clr(int r) {
-        if( r < 64 ) _bits0 &= ~(1L<<(r   ));
-        else         _bits1 &= ~(1L<<(r-64));
-        return _bits0!=0 || _bits1!=0;
-    }
-    @Override RegMaskRW and( RegMask mask ) {
-        if( mask==null ) return this;
-        _bits0 &= mask._bits0;
-        _bits1 &= mask._bits1;
-        return this;
-    }
-    @Override RegMaskRW sub( RegMask mask ) {
-        if( mask==null ) return this;
-        _bits0 &= ~mask._bits0;
-        _bits1 &= ~mask._bits1;
-        return this;
+    public static String reg(String[] regs, int i) {
+        return i<regs.length ? regs[i] : "[stk#"+i+"]";
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/codegen/RegMaskRW.java b/src/main/java/com/seaofnodes/simple/codegen/RegMaskRW.java
new file mode 100644
index 00000000..1da9a3b1
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/codegen/RegMaskRW.java
@@ -0,0 +1,36 @@
+package com.seaofnodes.simple.codegen;
+
+// Mutable regmask(writable)
+public class RegMaskRW extends RegMask {
+    public RegMaskRW(long x, long y) { super(x,y);  }
+    // clears bit at position r. Returns true if the mask is still not empty.
+    public boolean clr(int r) {
+        if( r < 64 ) _bits0 &= ~(1L<<(r   ));
+        else         _bits1 &= ~(1L<<(r-64));
+        return _bits0!=0 || _bits1!=0;
+    }
+    // sets bit at position r.
+    public void set(int r) {
+        if( r < 64 ) _bits0 |= (1L<<(r   ));
+        else         _bits1 |= (1L<<(r-64));
+    }
+    @Override RegMaskRW and( RegMask mask ) {
+        if( mask==null ) return this;
+        _bits0 &= mask._bits0;
+        _bits1 &= mask._bits1;
+        return this;
+    }
+    @Override RegMaskRW sub( RegMask mask ) {
+        if( mask==null ) return this;
+        _bits0 &= ~mask._bits0;
+        _bits1 &= ~mask._bits1;
+        return this;
+    }
+    public RegMaskRW or( RegMask mask ) {
+        if( mask!=null ) {
+            _bits0 |= mask._bits0;
+            _bits1 |= mask._bits1;
+        }
+        return this;
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/AddFNode.java b/src/main/java/com/seaofnodes/simple/node/AddFNode.java
index 7d4e2910..792da62e 100644
--- a/src/main/java/com/seaofnodes/simple/node/AddFNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/AddFNode.java
@@ -13,7 +13,7 @@ public class AddFNode extends Node {
     @Override public String glabel() { return "+"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("("), visited);
         in(2)._print0(sb.append("+"), visited);
         return sb.append(")");
diff --git a/src/main/java/com/seaofnodes/simple/node/AddNode.java b/src/main/java/com/seaofnodes/simple/node/AddNode.java
index bc65e79a..dd128e76 100644
--- a/src/main/java/com/seaofnodes/simple/node/AddNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/AddNode.java
@@ -15,7 +15,7 @@ public class AddNode extends Node {
     @Override public String glabel() { return "+"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("("), visited);
         in(2)._print0(sb.append("+"), visited);
         return sb.append(")");
@@ -96,7 +96,7 @@ public class AddNode extends Node {
         // If lhs.in(2) is not a constant, we add ourselves as a dependency
         // because if it later became a constant then we could make this
         // transformation.
-        if( lhs.in(2).addDep(this)._type.isConstant() && rhs._type.isConstant() )
+        if( addDep(lhs.in(2))._type.isConstant() && rhs._type.isConstant() )
             return new AddNode(lhs.in(1),new AddNode(lhs.in(2),rhs).peephole());
 
 
diff --git a/src/main/java/com/seaofnodes/simple/node/BoolNode.java b/src/main/java/com/seaofnodes/simple/node/BoolNode.java
index e6b87ce8..fd6448a2 100644
--- a/src/main/java/com/seaofnodes/simple/node/BoolNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/BoolNode.java
@@ -21,7 +21,7 @@ abstract public class BoolNode extends Node {
     public String glabel() { return op(); }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("("), visited);
         in(2)._print0(sb.append(op()), visited);
         return sb.append(")");
@@ -92,6 +92,18 @@ abstract public class BoolNode extends Node {
         Node copyF() { return new EQF(null,null); }
     }
 
+    public static class NE extends BoolNode {
+        public NE(Node lhs, Node rhs) { super(lhs,rhs); }
+        public String op() { return "!="; }
+        TypeInteger doOp(TypeInteger i1, TypeInteger i2) {
+            if( i1==i2 && i1.isConstant() ) return TRUE;
+            if( i1._max < i2._min || i1._min > i2._max ) return FALSE;
+            return BOOL;
+        }
+        Node copy(Node lhs, Node rhs) { return new NE(lhs,rhs); }
+        Node copyF() { throw Utils.TODO(); }
+    }
+
     public static class LT extends BoolNode {
         public LT(Node lhs, Node rhs) { super(lhs,rhs); }
         public String op() { return "<" ; }
diff --git a/src/main/java/com/seaofnodes/simple/node/CFGNode.java b/src/main/java/com/seaofnodes/simple/node/CFGNode.java
index 37d08fb0..7877f93a 100644
--- a/src/main/java/com/seaofnodes/simple/node/CFGNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/CFGNode.java
@@ -3,6 +3,7 @@ package com.seaofnodes.simple.node;
 import com.seaofnodes.simple.Ary;
 import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.type.*;
 import java.util.BitSet;
 import java.util.HashMap;
@@ -55,6 +56,13 @@ public abstract class CFGNode extends Node {
         return c;
     }
 
+    // Used by the encoding / final BB layout
+    public CFGNode uctrlSkipEmpty() {
+        CFGNode x = this, y;
+        while( x.nOuts() == 1 && (y=x.uctrl())!=null ) // Skip empty blocks
+            x = y;
+        return x;
+    }
 
     // ------------------------------------------------------------------------
     /**
@@ -65,7 +73,9 @@ public abstract class CFGNode extends Node {
      * See {@link <a href="https://en.wikipedia.org/wiki/Dominator_(graph_theory)">...</a>}
      */
     public int _idepth;
-    public int idepth() { return _idepth==0 ? (_idepth=idom().idepth()+1) : _idepth; }
+    public int idepth() {
+        return CodeGen.CODE.validIDepth(_idepth) ? _idepth : (_idepth=CodeGen.CODE.iDepthFrom(idom().idepth()));
+    }
 
     // Return the immediate dominator of this Node and compute dom tree depth.
     public CFGNode idom(Node dep) { return cfg(0); }
@@ -77,8 +87,8 @@ public abstract class CFGNode extends Node {
         CFGNode lhs = this;
         while( lhs != rhs ) {
             var comp = lhs.idepth() - rhs.idepth();
-            if( comp >= 0 ) lhs = ((CFGNode)lhs.addDep(dep)).idom();
-            if( comp <= 0 ) rhs = ((CFGNode)rhs.addDep(dep)).idom();
+            if( comp >= 0 ) lhs = (dep==null ? lhs : dep.addDep(lhs)).idom();
+            if( comp <= 0 ) rhs = (dep==null ? rhs : dep.addDep(rhs)).idom();
         }
         return lhs;
     }
@@ -99,9 +109,9 @@ public abstract class CFGNode extends Node {
     public LoopNode loop() { return _ltree._head; }
     public int loopDepth() { return _ltree==null ? 0 : _ltree.depth(); }
 
-    LoopTree _ltree;
-    int _pre;                   // Pre-order numbers for loop tree finding
-    private static class LoopTree {
+    public LoopTree _ltree;
+    public int _pre;            // Pre-order numbers for loop tree finding
+    static class LoopTree {
         LoopTree _par;
         final LoopNode _head;
         int _depth;
@@ -177,4 +187,9 @@ public abstract class CFGNode extends Node {
                 (this instanceof CallNode && usecfg instanceof FunNode) ||
                 (this instanceof ReturnNode && usecfg instanceof CallEndNode);
     }
+
+
+    public String label( CFGNode target ) {
+        return (target instanceof LoopNode ? "LOOP" : "L")+target._nid;
+    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/CProjNode.java b/src/main/java/com/seaofnodes/simple/node/CProjNode.java
index adc4e66f..94770f16 100644
--- a/src/main/java/com/seaofnodes/simple/node/CProjNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/CProjNode.java
@@ -10,10 +10,10 @@ import java.util.BitSet;
 public class CProjNode extends CFGNode {
 
     // Which slice of the incoming multipart value
-    public final int _idx;
+    public int _idx;
 
     // Debugging label
-    public final String _label;
+    public String _label;
 
     public CProjNode(Node ctrl, int idx, String label) {
         super(ctrl);
@@ -24,7 +24,7 @@ public class CProjNode extends CFGNode {
 
     @Override public String label() { return _label; }
 
-    @Override StringBuilder _print1(StringBuilder sb, BitSet visited) { return sb.append(_label); }
+    @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) { return sb.append(_label); }
 
     @Override public boolean blockHead() { return true; }
 
@@ -46,15 +46,21 @@ public class CProjNode extends CFGNode {
         }
 
         // Flip a negating if-test, to remove the not
-        if( ctrl() instanceof IfNode iff && iff.pred().addDep(this) instanceof NotNode not )
+        if( ctrl() instanceof IfNode iff && addDep(iff.pred()) instanceof NotNode not )
             return new CProjNode(new IfNode(iff.ctrl(),not.in(1)).peephole(),1-_idx,_idx==0 ? "False" : "True");
 
         // Copy of some other input
         return ((MultiNode)ctrl()).pcopy(_idx);
     }
 
+    // Only called during basic-block layout, inverts a T/F CProj
+    public void invert() {
+        _label = _idx == 0 ? "False" : "True";
+        _idx = 1-_idx;
+    }
+
     @Override
-    boolean eq( Node n ) { return _idx == ((CProjNode)n)._idx; }
+    public boolean eq( Node n ) { return _idx == ((CProjNode)n)._idx; }
 
     @Override
     int hash() { return _idx; }
diff --git a/src/main/java/com/seaofnodes/simple/node/CallEndNode.java b/src/main/java/com/seaofnodes/simple/node/CallEndNode.java
index 03a4462d..f99a0b89 100644
--- a/src/main/java/com/seaofnodes/simple/node/CallEndNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/CallEndNode.java
@@ -1,7 +1,7 @@
 package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.type.*;
 import java.util.BitSet;
 
@@ -23,7 +23,7 @@ public class CallEndNode extends CFGNode implements MultiNode {
     public CallNode call() { return (CallNode)in(0); }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         sb.append("cend( ");
         sb.append( in(0) instanceof CallNode ? "Call, " : "----, ");
         for( int i=1; i<nIns()-1; i++ )
@@ -38,7 +38,7 @@ public class CallEndNode extends CFGNode implements MultiNode {
             return TypeTuple.RET.dual();
         Type ret = Type.BOTTOM;
         TypeMem mem = TypeMem.BOT;
-        if( call.fptr().addDep(this)._type instanceof TypeFunPtr tfp ) {
+        if( addDep(call.fptr())._type instanceof TypeFunPtr tfp ) {
             ret = tfp.ret();
             // Here, if I can figure out I've found *all* callers, then I can meet
             // across the linked returns and join with the function return type.
@@ -70,8 +70,9 @@ public class CallEndNode extends CFGNode implements MultiNode {
                     assert fun.in(1) instanceof StartNode && fun.in(2)==call;
                     // Disallow self-recursive inlining (loop unrolling by another name)
                     CFGNode idom = call;
-                    while( !(idom instanceof FunNode fun2) )
+                    while( !(idom instanceof FunNode) )
                         idom = idom.idom();
+                    // Inline?
                     if( idom != fun ) {
                         // Trivial inline: rewrite
                         _folding = true;
@@ -81,13 +82,16 @@ public class CallEndNode extends CFGNode implements MultiNode {
                         fun.setDef(2,call.ctrl());  // Bypass the Call;
                         fun.ret().setDef(3,null);   // Return is folding also
                         CodeGen.CODE.addAll(fun._outputs);
+                        // Inlining immediately blows all cache idepth fields past the inline point.
+                        // Bump the global version number invalidating them en-masse.
+                        CodeGen.CODE.invalidateIDepthCaches();
                         return this;
                     }
                 } else {
-                    fun.addDep(this);
+                    addDep(fun);
                 }
             } else { // Function ptr has multiple users (so maybe multiple call sites)
-                fptr.addDep(this);
+                addDep(fptr);
             }
         }
 
@@ -97,4 +101,34 @@ public class CallEndNode extends CFGNode implements MultiNode {
     @Override public Node pcopy(int idx) {
         return _folding ? in(1).in(idx) : null;
     }
+
+    // ------------
+    // MachNode specifics, shared across all CPUs
+    public int _xslot;
+    private RegMask _retMask;
+    private RegMask _kills;
+    public void cacheRegs(CodeGen code) {
+        // Return mask depends on TFP (either GPR or FPR)
+        _retMask = code._mach.retMask(call().tfp());
+        // Kill mask is all caller-saves, and any mirror stack slots for args
+        // in registers.
+        RegMaskRW kills = code._callerSave.copy();
+        // Start of stack slots
+        int maxReg = code._mach.regs().length;
+        // Incoming function arg slots, all low numbered in the RA
+        int fslot = fun()._maxArgSlot;
+        // Killed slots for this calls outgoing args
+        int xslot = code._mach.maxArgSlot(call().tfp());
+        _xslot = (maxReg+fslot)+xslot;
+        for( int i=0; i<xslot; i++ )
+            kills.set((maxReg+fslot)+i);
+        _kills = kills;
+    }
+    public String op() { return "cend"; }
+    public RegMask regmap(int i) { return null; }
+    public RegMask outregmap() { return null; }
+    public RegMask outregmap(int idx) { return idx==2  ? _retMask : null; }
+    public RegMask killmap() { return _kills; }
+    public void encoding( Encoding enc ) { }
+    public void asm(CodeGen code, SB sb) {  }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/CallNode.java b/src/main/java/com/seaofnodes/simple/node/CallNode.java
index c9bbcc52..78a0b153 100644
--- a/src/main/java/com/seaofnodes/simple/node/CallNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/CallNode.java
@@ -21,7 +21,7 @@ public class CallNode extends CFGNode {
 
     @Override public String label() { return "Call"; }
 
-    @Override StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         String fname = name();
         if( fname == null ) fptr()._print0(sb,visited);
         else sb.append(fname);
@@ -50,6 +50,10 @@ public class CallNode extends CFGNode {
     // Error if not a TFP
     public TypeFunPtr tfp() { return (TypeFunPtr)fptr()._type; }
 
+    // Call is to an externally supplied code
+    public boolean external() { return false; }
+
+
     // Find the Call End from the Call
     public CallEndNode cend() {
         // Always in use slot 0
@@ -87,6 +91,7 @@ public class CallNode extends CFGNode {
         // Link: call calls target function.  Linking makes the target FunNode
         // point to this Call, and all his Parms point to the call arguments;
         // also the CallEnd points to the Return.
+        Node progress = null;
         if( fptr()._type instanceof TypeFunPtr tfp && tfp.nargs() == nargs() ) {
             // If fidxs is negative, then infinite unknown functions
             long fidxs = tfp.fidxs();
@@ -98,12 +103,12 @@ public class CallNode extends CFGNode {
                     TypeFunPtr tfp0 = tfp.makeFrom(fidx);
                     FunNode fun = CodeGen.CODE.link(tfp0);
                     if( fun!=null && !fun._folding && !linked(fun) )
-                        link(fun);
+                        progress = link(fun);
                 }
             }
         }
 
-        return null;
+        return progress;
     }
 
     // True if Fun is linked to this Call
@@ -116,7 +121,7 @@ public class CallNode extends CFGNode {
 
 
     // Link so this calls fun
-    private void link( FunNode fun ) {
+    private Node link( FunNode fun ) {
         assert !linked(fun);
         fun.addDef(this);
         for( Node use : fun._outputs )
@@ -124,7 +129,7 @@ public class CallNode extends CFGNode {
                 parm.addDef(parm._idx==0 ? new ConstantNode(cend()._rpc).peephole() : arg(parm._idx));
         // Call end points to function return
         CodeGen.CODE.add(cend()).addDef(fun.ret());
-        assert linked(fun);
+        return this;
     }
 
     // Unlink all linked functions
@@ -134,7 +139,7 @@ public class CallNode extends CFGNode {
                 assert linked(fun);
                 int idx = fun._inputs.find(this);
                 for( Node use : fun._outputs )
-                    if( use instanceof ParmNode parm )
+                    if( use instanceof ParmNode )
                         use.delDef(idx);
                 fun.delDef(idx);
                 cend().delDef(cend()._inputs.find(fun.ret()));
diff --git a/src/main/java/com/seaofnodes/simple/node/CalleeSaveNode.java b/src/main/java/com/seaofnodes/simple/node/CalleeSaveNode.java
index d4a937bd..0afc5827 100644
--- a/src/main/java/com/seaofnodes/simple/node/CalleeSaveNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/CalleeSaveNode.java
@@ -1,10 +1,8 @@
 package com.seaofnodes.simple.node;
 
-import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.type.Type;
-import java.util.BitSet;
-import java.io.ByteArrayOutputStream;
 
 public class CalleeSaveNode extends ProjNode implements MachNode {
     final RegMask _mask;
@@ -18,7 +16,7 @@ public class CalleeSaveNode extends ProjNode implements MachNode {
     }
     @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return _mask; }
-    @Override public int encoding(ByteArrayOutputStream bytes) { return 0; }
+    @Override public void encoding( Encoding enc ) { }
 
     @Override public Type compute() { return Type.BOTTOM; }
     @Override public Node idealize() { return null; }
diff --git a/src/main/java/com/seaofnodes/simple/node/CastNode.java b/src/main/java/com/seaofnodes/simple/node/CastNode.java
index 5a92802c..0947bcf0 100644
--- a/src/main/java/com/seaofnodes/simple/node/CastNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/CastNode.java
@@ -31,7 +31,7 @@ public class CastNode extends Node {
     @Override public boolean isConst() { return true; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         return in(1)._print0(sb.append(label()), visited);
     }
 
@@ -46,7 +46,7 @@ public class CastNode extends Node {
     }
 
     @Override
-    boolean eq(Node n) {
+    public boolean eq(Node n) {
         CastNode cast = (CastNode)n; // Contract
         return _t==cast._t;
     }
diff --git a/src/main/java/com/seaofnodes/simple/node/ConstantNode.java b/src/main/java/com/seaofnodes/simple/node/ConstantNode.java
index f7ebc006..79f301c1 100644
--- a/src/main/java/com/seaofnodes/simple/node/ConstantNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ConstantNode.java
@@ -42,13 +42,13 @@ public class ConstantNode extends Node {
     public String uniqueName() { return "Con_" + _nid; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         if( _con instanceof TypeFunPtr tfp && tfp.isConstant() ) {
             FunNode fun = CodeGen.CODE.link(tfp);
-            if( fun._name != null )
+            if( fun!=null && fun._name != null )
                 return sb.append("{ ").append(fun._name).append("}");
         }
-        return sb.append(_con.print(new SB()));
+        return sb.append(_con==null ? "---" : _con.print(new SB()));
     }
 
     @Override public boolean isConst() { return true; }
@@ -60,7 +60,7 @@ public class ConstantNode extends Node {
     public Node idealize() { return null; }
 
     @Override
-    boolean eq(Node n) {
+    public boolean eq(Node n) {
         ConstantNode con = (ConstantNode)n; // Contract
         return _con==con._con;
     }
diff --git a/src/main/java/com/seaofnodes/simple/node/CtrlNode.java b/src/main/java/com/seaofnodes/simple/node/CtrlNode.java
index 61d9c310..eda7d684 100644
--- a/src/main/java/com/seaofnodes/simple/node/CtrlNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/CtrlNode.java
@@ -8,7 +8,7 @@ import java.util.BitSet;
 public class CtrlNode extends CFGNode {
     public CtrlNode() { super(CodeGen.CODE._start); }
     @Override public String label() { return "Ctrl"; }
-    @Override StringBuilder _print1(StringBuilder sb, BitSet visited) { return sb.append("Cctrl"); }
+    @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) { return sb.append("Cctrl"); }
     @Override public boolean isConst() { return true; }
     @Override  public Type compute() { return Type.CONTROL; }
     @Override public Node idealize() { return null; }
diff --git a/src/main/java/com/seaofnodes/simple/node/DivFNode.java b/src/main/java/com/seaofnodes/simple/node/DivFNode.java
index a6e459c9..633f3224 100644
--- a/src/main/java/com/seaofnodes/simple/node/DivFNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/DivFNode.java
@@ -13,7 +13,7 @@ public class DivFNode extends Node {
     @Override public String glabel() { return "/"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("("), visited);
         in(2)._print0(sb.append("/"), visited);
         return sb.append(")");
diff --git a/src/main/java/com/seaofnodes/simple/node/DivNode.java b/src/main/java/com/seaofnodes/simple/node/DivNode.java
index 0d5ed297..41518311 100644
--- a/src/main/java/com/seaofnodes/simple/node/DivNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/DivNode.java
@@ -12,7 +12,7 @@ public class DivNode extends Node {
     @Override public String glabel() { return "//"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("("), visited);
         in(2)._print0(sb.append("/"), visited);
         return sb.append(")");
diff --git a/src/main/java/com/seaofnodes/simple/node/FRefNode.java b/src/main/java/com/seaofnodes/simple/node/FRefNode.java
index f0c4045d..6093b8a6 100644
--- a/src/main/java/com/seaofnodes/simple/node/FRefNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/FRefNode.java
@@ -19,7 +19,7 @@ public class FRefNode extends ConstantNode {
 
     @Override public String uniqueName() { return "FRef_" + _nid; }
 
-    @Override StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         return sb.append("FRef_").append(_n);
     }
 
@@ -30,6 +30,6 @@ public class FRefNode extends ConstantNode {
 
     public Parser.ParseException err() { return Parser.error("Undefined name '"+_n._name+"'",_n._loc); }
 
-    @Override boolean eq(Node n) { return this==n; }
+    @Override public boolean eq(Node n) { return this==n; }
     @Override int hash() { return _n._idx; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/FunNode.java b/src/main/java/com/seaofnodes/simple/node/FunNode.java
index 38aa83a0..b41a7e54 100644
--- a/src/main/java/com/seaofnodes/simple/node/FunNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/FunNode.java
@@ -1,10 +1,13 @@
 package com.seaofnodes.simple.node;
 
+
 import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
+import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeFunPtr;
 import com.seaofnodes.simple.type.TypeTuple;
-
 import java.util.BitSet;
 import static com.seaofnodes.simple.codegen.CodeGen.CODE;
 
@@ -109,8 +112,11 @@ public class FunNode extends RegionNode {
         return null;
     }
 
-    // Bypass Region idom, always assume depth == 1, one more than Start
-    @Override public int idepth() { return (_idepth=1); }
+    // Bypass Region idom, always assume depth == 1, one more than Start,
+    // unless folding then just a ID on input#1
+    @Override public int idepth() {
+        return _folding ? super.idepth() : CodeGen.CODE.iDepthAt(1);
+    }
     // Bypass Region idom, always assume idom is Start
     @Override public CFGNode idom(Node dep) { return cfg(1); }
 
@@ -161,4 +167,53 @@ public class FunNode extends RegionNode {
         if( in ) body.set(n._nid);
         return in;
     }
+
+
+    // ------------
+    // MachNode specifics, shared across all CPUs
+
+    // Function may call other functions?  X86 requires 16b aligned SP on
+    // outbound calls, but not leaf.  Set during an unrelated RA scan.
+    public boolean _hasCalls;
+
+    // Maximum incoming argument slot, based on function type
+    public int _maxArgSlot;
+
+    // Frame adjust, including padding, set during early Encoding
+    public int _frameAdjust;
+
+    public String op() { return _frameAdjust==0 ? "entry" : "subi"; }
+    public void postSelect(CodeGen code) {
+        code.link(this);
+        // Max slot seen past space reserved for incoming arguments
+        _maxArgSlot = code._mach.maxArgSlot(sig());
+    }
+    public RegMask regmap(int i) { return null; }
+    public RegMask outregmap() { return null; }
+    public void encoding( Encoding enc ) { throw Utils.TODO();  }
+    public void asm(CodeGen code, SB sb) {
+        if( _frameAdjust!=0 )
+            sb.p("rsp -= #").p(_frameAdjust);
+    }
+
+    public void computeFrameAdjust(CodeGen code, int maxReg) {
+        // Max slot seen, or 0.
+        int maxSlot = Math.max(maxReg - code._mach.regs().length,_maxArgSlot);
+        // Frame adjust before rounding, can be negative for no spills
+        int size = maxSlot - _maxArgSlot;
+        _frameAdjust = size*8;
+    }
+
+    // Given a high register number and during encoding compute the stack
+    // pointer offset.  Pre-RA we lack the fun._frameAdjust.  We also need a
+    // FunNode.
+    public int computeStackOffset(CodeGen code, int reg) {
+        String[] regs = code._mach.regs();
+        int stackSlot = reg - regs.length;
+        int slotRotate = stackSlot < _maxArgSlot
+            ? stackSlot + (_frameAdjust>>3)
+            : stackSlot - _maxArgSlot;
+        return slotRotate*8;
+    }
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/IfNode.java b/src/main/java/com/seaofnodes/simple/node/IfNode.java
index e04522b0..5d90449e 100644
--- a/src/main/java/com/seaofnodes/simple/node/IfNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/IfNode.java
@@ -1,10 +1,9 @@
 package com.seaofnodes.simple.node;
 
+import com.seaofnodes.simple.Utils;
 import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.IterPeeps;
 import com.seaofnodes.simple.type.*;
 import java.util.BitSet;
-import java.util.HashSet;
 
 public class IfNode extends CFGNode implements MultiNode {
 
@@ -20,7 +19,9 @@ public class IfNode extends CFGNode implements MultiNode {
     @Override
     public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         sb.append("if( ");
-        return in(1)._print0(sb, visited).append(" )");
+        if( in(1)==null ) sb.append("never");
+        else in(1)._print0(sb, visited);
+        return sb.append(" )");
     }
 
     public Node ctrl() { return in(0); }
@@ -57,11 +58,40 @@ public class IfNode extends CFGNode implements MultiNode {
         // test on either the true or false branch, that side wins.
         if( !pred()._type.isHighOrConst() )
             for( CFGNode dom = idom(), prior=this; dom!=null;  prior = dom, dom = dom.idom() )
-                if( dom.addDep(this) instanceof IfNode iff && iff.pred().addDep(this)==pred() && prior instanceof CProjNode prj ) {
+                if( addDep(dom) instanceof IfNode iff && addDep(iff.pred())==pred() && prior instanceof CProjNode prj ) {
                     setDef(1,con( prj._idx==0 ? 1 : 0 ));
                     return this;
                 }
         return null;
     }
 
+    // MachNode variants need to support this and negate the conditional test.
+    // The following CProjs will be inverted by the caller.
+    public void negate() { throw Utils.TODO(); }
+
+    // Negate the sense of a test
+    public static String negate( String bop ) {
+        return switch( bop ) {
+        case "<"  -> ">=";
+        case "<=" -> ">" ;
+        case "==" -> "!=";
+        case "!=" -> "==";
+        case ">"  -> "<=";
+        case ">=" -> "<" ;
+        default -> throw Utils.TODO();
+        };
+    }
+
+    // Swap compare operands
+    public static String swap( String bop ) {
+        return switch( bop ) {
+        case "<"  -> ">" ;
+        case "<=" -> ">=";
+        case "==" -> "!=";
+        case "!=" -> "==";
+        case ">"  -> "<" ;
+        case ">=" -> "<=";
+        default -> throw Utils.TODO();
+        };
+    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/LoadNode.java b/src/main/java/com/seaofnodes/simple/node/LoadNode.java
index b70a938d..6147de81 100644
--- a/src/main/java/com/seaofnodes/simple/node/LoadNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/LoadNode.java
@@ -20,7 +20,7 @@ public class LoadNode extends MemOpNode {
      * @param off   The offset inside the struct base
      */
     public LoadNode(Parser.Lexer loc, String name, int alias, Type glb, Node mem, Node ptr, Node off) {
-        super(loc, name, alias, glb, mem, ptr, off);
+        super(loc, name, alias, true, glb, mem, ptr, off);
     }
 
     // GraphVis DOT code (must be valid Java identifiers) and debugger labels
@@ -29,7 +29,7 @@ public class LoadNode extends MemOpNode {
     @Override public String glabel() { return "." +_name; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) { return sb.append(".").append(_name); }
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) { return sb.append(".").append(_name); }
 
     @Override
     public Type compute() {
@@ -77,7 +77,7 @@ public class LoadNode extends MemOpNode {
         while( true ) {
             switch( mem ) {
             case StoreNode st:
-                if( ptr == st.ptr().addDep(this) && off() == st.off() )
+                if( ptr == addDep(st.ptr()) && off() == st.off() )
                     return extend(castRO(st.val())); // Proved equal
                 // Can we prove unequal?  Offsets do not overlap?
                 if( !off()._type.join(st.off()._type).isHigh() && // Offsets overlap
@@ -88,7 +88,7 @@ public class LoadNode extends MemOpNode {
                 break;
             case PhiNode phi:
                 // Assume related
-                phi.addDep(this);
+                addDep(phi);
                 break outer;
             case ConstantNode top: break outer;  // Assume shortly dead
             case ProjNode mproj: // Memory projection
@@ -182,7 +182,7 @@ public class LoadNode extends MemOpNode {
         if( px==null ) return false;
         if( px._type instanceof TypeMem mem && mem._t.isHighOrConst() ) return true;
         if( px instanceof StoreNode st1 && ptr()==st1.ptr() && off()==st1.off() ) return true;
-        px.addDep(this);
+        addDep(px);
         return false;
     }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/LogicalNode.java b/src/main/java/com/seaofnodes/simple/node/LogicalNode.java
index 8c3452bf..e8552789 100644
--- a/src/main/java/com/seaofnodes/simple/node/LogicalNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/LogicalNode.java
@@ -13,7 +13,7 @@ public abstract class LogicalNode extends Node {
     abstract String op();
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("("), visited);
         in(2)._print0(sb.append(op()), visited);
         return sb.append(")");
diff --git a/src/main/java/com/seaofnodes/simple/node/LoopNode.java b/src/main/java/com/seaofnodes/simple/node/LoopNode.java
index d2b0e36c..2fa070bc 100644
--- a/src/main/java/com/seaofnodes/simple/node/LoopNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/LoopNode.java
@@ -2,9 +2,10 @@ package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeMem;
 import com.seaofnodes.simple.type.TypeInteger;
+import com.seaofnodes.simple.type.TypeMem;
 import java.util.BitSet;
 import java.util.HashSet;
 
@@ -25,7 +26,9 @@ public class LoopNode extends RegionNode {
     }
 
     // Bypass Region idom, same as the default idom() using use in(1) instead of in(0)
-    @Override public int idepth() { return _idepth==0 ? (_idepth=idom().idepth()+1) : _idepth; }
+    public int idepth() {
+        return CodeGen.CODE.validIDepth(_idepth) ? _idepth : (_idepth=CodeGen.CODE.iDepthFrom(idom().idepth()));
+    }
     // Bypass Region idom, same as the default idom() using use in(1) instead of in(0)
     @Override public CFGNode idom(Node dep) { return entry(); }
 
@@ -39,42 +42,48 @@ public class LoopNode extends RegionNode {
         while( x != this ) {
             if( x instanceof CProjNode exit && exit.in(0) instanceof IfNode iff ) {
                 CFGNode other = iff.cproj(1-exit._idx);
-                if( other!=null && other.loopDepth() < loopDepth() )
+                if( other!=null && other._ltree != _ltree && nested(_ltree,other._ltree) )
                     return stop; // Found an exit, not an infinite loop
             }
             x = x.idom();
         }
         // Found a no-exit loop.  Insert an exit
-        NeverNode iff = new NeverNode(back());
-        for( Node use : _outputs )
-            if( use instanceof PhiNode )
-                iff.addDef(use);
+        NeverNode iff = new NeverNode(back()); // Ideal never-branch
         CProjNode t = new CProjNode(iff,0,"True" ).init();
         CProjNode f = new CProjNode(iff,1,"False").init();
-        setDef(2,f);
+        setDef(2,t);            // True continues loop, False (never) exits loop
+        ReturnNode ret = fun.ret();
+        iff._ltree = t._ltree = _ltree;
+        ret._ltree = f._ltree = stop._ltree;
 
         // Now fold control into the exit.  Might have 1 valid exit, or an
         // XCtrl or a bunch of prior NeverNode exits.
         Node top = new ConstantNode(Type.TOP).peephole();
-        ReturnNode ret = fun.ret();
+        Node memout = new MemMergeNode(false);
+        memout.addDef(f); // placeholder for control
+        for( Node u : _outputs )
+            if( u instanceof PhiNode phi && phi._type.isa(TypeMem.BOT) )
+                memout.addDef(phi);
+
         Node ctrl = ret.ctrl(), mem = ret.mem(), expr = ret.expr();
-        if( ctrl._type != Type.XCONTROL ) {
+        if( ctrl!=null && ctrl._type != Type.XCONTROL ) {
             // Perfect aligned exit?
             if( !(ctrl instanceof RegionNode r &&
                   mem  instanceof PhiNode pmem && pmem.region()==r &&
                   expr instanceof PhiNode prez && prez.region()==r ) ) {
                 // Nope, insert an aligned exit layer
-                ctrl = new RegionNode(_loc,null,ctrl).init();
-                mem  = new    PhiNode((RegionNode)ctrl,mem ).init();
-                expr = new    PhiNode((RegionNode)ctrl,expr).init();
+                RegionNode r = new RegionNode(_loc,null,ctrl).init();
+                ctrl = r;  r._ltree = stop._ltree;
+                mem  = new PhiNode(r,mem ).init();
+                expr = new PhiNode(r,expr).init();
             }
             // Append new Never exit
-            ctrl.addDef(t  );
-            mem .addDef(top);
+            ctrl.addDef(f  );
+            mem .addDef(memout);
             expr.addDef(top);
         } else {
-            ctrl = t;
-            mem  = top;
+            ctrl = f;
+            mem  = memout;
             expr = top;
         }
         ret.setDef(0,ctrl);
@@ -83,4 +92,12 @@ public class LoopNode extends RegionNode {
 
         return stop;
     }
+
+    private static boolean nested(LoopTree inner, LoopTree outer) {
+        for( ; inner!=null; inner = inner._par )
+            if( inner == outer )
+                return true;
+        return false;
+    }
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/MachNode.java b/src/main/java/com/seaofnodes/simple/node/MachNode.java
index ecdbc651..f63b3651 100644
--- a/src/main/java/com/seaofnodes/simple/node/MachNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/MachNode.java
@@ -1,10 +1,7 @@
 package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.Machine;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.codegen.*;
 
 public interface MachNode {
 
@@ -12,7 +9,7 @@ public interface MachNode {
     default Machine machine() { return CodeGen.CODE._mach; }
 
     // Run a post-instruction-selection action
-    default void postSelect() { }
+    default void postSelect( CodeGen code ) { }
 
     // Register mask allowed on input i.  0 for no register.
     RegMask regmap( int i );
@@ -47,8 +44,8 @@ public interface MachNode {
     // Make a clone of a cheap instruction
     default Node copy() { return null; }
 
-    // Encoding is appended into the byte array; size is returned
-    int encoding(ByteArrayOutputStream bytes);
+    // Encoding is appended, relocations gathered.
+    void encoding( Encoding enc );
 
     // Human-readable form appended to the SB.  Things like the encoding,
     // indentation, leading address or block labels not printed here.
diff --git a/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java b/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java
index 1495a703..32c25a8b 100644
--- a/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java
@@ -30,7 +30,7 @@ public class MemMergeNode extends Node {
     @Override public boolean isMem() { return true; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         sb.append(_inProgress ? "Merge[" : "MEM[ ");
         for( int j=2; j<nIns(); j++ ) {
             sb.append(j);
@@ -65,11 +65,18 @@ public class MemMergeNode extends Node {
         if( inProgress() ) return null;
 
         // If not merging any memory (all memory is just the default)
-        if( nIns()==2 )
+        if( allDefault() )
             return in(1);       // Become default memory
 
         return null;
     }
+    private boolean allDefault() {
+        for( int i=2; i<nIns(); i++ )
+            if( in(1) != in(i) )
+                return false;
+        return true;
+    }
+
 
     public Node in( Var v ) { return in(v._idx); }
 
@@ -149,7 +156,7 @@ public class MemMergeNode extends Node {
         }
     }
 
-    @Override boolean eq( Node n ) {
+    @Override public boolean eq( Node n ) {
         return this==n || !_inProgress;
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/MemOpNode.java b/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
index cba4dc1b..058c86fa 100644
--- a/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
@@ -9,26 +9,49 @@ import java.util.BitSet;
 
 /**
  * Convenience common base for Load and Store.
+ *
+ * 0 - Control
+ * 1 - Memory
+ * 2 - Base of object, OOP
+ * 3 - Offset, integer types
+ * 4 - Value, for Stores only
  */
 public abstract class MemOpNode extends Node {
 
-    public final String _name;
+    // The equivalence alias class
     public final int _alias;
+
+    // True if load-like, false if store-like.
+    //
+    // Stores produce memory (maybe as part of a tuple with other things),
+    // loads do not.
+    //
+    // Loads might pick up anti-dependences on prior Stores, and never cause an
+    // anti-dependence themselves.
+    //
+    // Stores must maximally sink to the least dominator use.  Loads can be
+    // opportunistically hoisted.
+    public final boolean _isLoad;
+
     // Declared type; not final because it might be a forward-reference
     // which will be lazily improved when the reference is declared.
     public Type _declaredType;
+
+    // A debug name, no semantic meaning
+    public final String _name;
     // Source location for late reported errors
     public final Parser.Lexer _loc;
 
-    public MemOpNode(Parser.Lexer loc, String name, int alias, Type glb, Node mem, Node ptr, Node off) {
+    public MemOpNode(Parser.Lexer loc, String name, int alias, boolean isLoad, Type glb, Node mem, Node ptr, Node off) {
         super(null, mem, ptr, off);
         _name  = name;
         _alias = alias;
         _declaredType = glb;
         _loc = loc;
+        _isLoad = isLoad;
     }
-    public MemOpNode(Parser.Lexer loc, String name, int alias, Type glb, Node mem, Node ptr, Node off, Node value) {
-        this(loc,name, alias, glb, mem, ptr, off);
+    public MemOpNode(Parser.Lexer loc, String name, int alias, boolean isLoad, Type glb, Node mem, Node ptr, Node off, Node value) {
+        this(loc,name, alias, isLoad, glb, mem, ptr, off);
         addDef(value);
     }
     public MemOpNode( Node mach, MemOpNode mop ) {
@@ -36,7 +59,20 @@ public abstract class MemOpNode extends Node {
         _name  = mop==null ? null : mop._name;
         _alias = mop==null ? 0    : mop._alias;
         _loc   = mop==null ? null : mop._loc;
+        _isLoad= mop==null ? true : mop._isLoad;
         _declaredType = mop==null ? Type.BOTTOM : mop._declaredType;
+        if( mop==null )
+            throw Utils.TODO("Load or not");
+    }
+
+    // Used by M2 when translating graph to Simple
+    public MemOpNode( boolean isLoad ) {
+        super((Node)null);
+        _name         = null;
+        _alias        = 0;
+        _loc          = null;
+        _isLoad       = isLoad;
+        _declaredType = Type.BOTTOM;
     }
 
     //
@@ -47,12 +83,12 @@ public abstract class MemOpNode extends Node {
     public Node ptr() { return in(2); }
     public Node off() { return in(3); }
 
-    @Override StringBuilder _print1( StringBuilder sb, BitSet visited ) { return _printMach(sb,visited);  }
+    @Override public StringBuilder _print1( StringBuilder sb, BitSet visited ) { return _printMach(sb,visited);  }
     public StringBuilder _printMach( StringBuilder sb, BitSet visited ) { throw Utils.TODO(); }
 
 
     @Override
-    boolean eq(Node n) {
+    public boolean eq(Node n) {
         MemOpNode mem = (MemOpNode)n; // Invariant
         return _alias==mem._alias;    // When comparing types error to use "equals"; always use "=="
     }
diff --git a/src/main/java/com/seaofnodes/simple/node/MinusFNode.java b/src/main/java/com/seaofnodes/simple/node/MinusFNode.java
index 2b749ba3..99fc3144 100644
--- a/src/main/java/com/seaofnodes/simple/node/MinusFNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/MinusFNode.java
@@ -13,7 +13,7 @@ public class MinusFNode extends Node {
     @Override public String glabel() { return "-"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("(-"), visited);
         return sb.append(")");
     }
diff --git a/src/main/java/com/seaofnodes/simple/node/MinusNode.java b/src/main/java/com/seaofnodes/simple/node/MinusNode.java
index dd2cbd26..e06e0c69 100644
--- a/src/main/java/com/seaofnodes/simple/node/MinusNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/MinusNode.java
@@ -14,7 +14,7 @@ public class MinusNode extends Node {
     @Override public String glabel() { return "-"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("(-"), visited);
         return sb.append(")");
     }
diff --git a/src/main/java/com/seaofnodes/simple/node/MulFNode.java b/src/main/java/com/seaofnodes/simple/node/MulFNode.java
index 2d44a9fb..6fbf4bbb 100644
--- a/src/main/java/com/seaofnodes/simple/node/MulFNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/MulFNode.java
@@ -13,7 +13,7 @@ public class MulFNode extends Node {
     @Override public String glabel() { return "*"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("("), visited);
         in(2)._print0(sb.append("*"), visited);
         return sb.append(")");
diff --git a/src/main/java/com/seaofnodes/simple/node/MulNode.java b/src/main/java/com/seaofnodes/simple/node/MulNode.java
index 80f8c319..384dbace 100644
--- a/src/main/java/com/seaofnodes/simple/node/MulNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/MulNode.java
@@ -13,7 +13,7 @@ public class MulNode extends Node {
     @Override public String glabel() { return "*"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("("), visited);
         in(2)._print0(sb.append("*"), visited);
         return sb.append(")");
diff --git a/src/main/java/com/seaofnodes/simple/node/NeverNode.java b/src/main/java/com/seaofnodes/simple/node/NeverNode.java
index 26198500..516f218b 100644
--- a/src/main/java/com/seaofnodes/simple/node/NeverNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/NeverNode.java
@@ -9,7 +9,8 @@ import java.util.BitSet;
 
 // "Never true" for infinite loop exits
 public class NeverNode extends IfNode {
-    public NeverNode(Node ctrl) { super(ctrl,Parser.ZERO); }
+    public NeverNode(NeverNode ctrl) { super(ctrl); }
+    public NeverNode(Node ctrl) { super(ctrl,null); }
 
     @Override public String label() { return "Never"; }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/NewNode.java b/src/main/java/com/seaofnodes/simple/node/NewNode.java
index 80545d66..5a8c1b6b 100644
--- a/src/main/java/com/seaofnodes/simple/node/NewNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/NewNode.java
@@ -1,7 +1,9 @@
 package com.seaofnodes.simple.node;
 
-import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.type.*;
 import java.util.BitSet;
 
 /**
@@ -39,7 +41,7 @@ public class NewNode extends Node implements MultiNode {
     }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         sb.append("new ");
         return sb.append(_ptr._obj.str());
     }
@@ -76,8 +78,42 @@ public class NewNode extends Node implements MultiNode {
     public Node idealize() { return null; }
 
     @Override
-    boolean eq(Node n) { return this == n; }
+    public boolean eq(Node n) { return this == n; }
 
     @Override
     int hash() { return _ptr.hashCode(); }
+
+    // ------------
+    // MachNode specifics, shared across all CPUs
+    public int _arg2Reg, _xslot;
+    private RegMask _arg3Mask;
+    private RegMask _retMask;
+    private RegMask _kills;
+    public void cacheRegs(CodeGen code) {
+        _arg2Reg  = code._mach.callArgMask(TypeFunPtr.CALLOC,2,0).firstReg();
+        _arg3Mask = code._mach.callArgMask(TypeFunPtr.CALLOC,3,0);
+        // Return mask depends on TFP (either GPR or FPR)
+        _retMask = code._mach.retMask(TypeFunPtr.CALLOC);
+        // Kill mask is all caller-saves, and any mirror stack slots for args
+        // in registers.
+        RegMaskRW kills = code._callerSave.copy();
+        // Start of stack slots
+        int maxReg = code._mach.regs().length;
+        // Incoming function arg slots, all low numbered in the RA
+        int fslot = cfg0().fun()._maxArgSlot;
+        // Killed slots for this calls outgoing args
+        int xslot = code._mach.maxArgSlot(TypeFunPtr.CALLOC);
+        _xslot = (maxReg+fslot)+xslot;
+        for( int i=0; i<xslot; i++ )
+            kills.set((maxReg+fslot)+i);
+        _kills = kills;
+    }
+    public String op() { return "alloc"; }
+    public RegMask regmap(int i) { return i==1 ? _arg3Mask : null; }
+    public RegMask outregmap() { return null; }
+    public RegMask outregmap(int idx) { return idx==1  ? _retMask : null; }
+    public RegMask killmap() { return _kills; }
+    public void asm(CodeGen code, SB sb) {
+        sb.p("#calloc, ").p(code.reg(size()));
+    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/Node.java b/src/main/java/com/seaofnodes/simple/node/Node.java
index e8043854..4ca95cae 100644
--- a/src/main/java/com/seaofnodes/simple/node/Node.java
+++ b/src/main/java/com/seaofnodes/simple/node/Node.java
@@ -16,14 +16,14 @@ import static com.seaofnodes.simple.codegen.CodeGen.CODE;
  * The Node class provides common functionality used by all subtypes.
  * Subtypes of Node specialize by overriding methods.
  */
-public abstract class Node {
+public abstract class Node implements Cloneable {
 
     /**
      * Each node has a unique dense Node ID within a compilation context
      * The ID is useful for debugging, for using as an offset in a bitvector,
      * as well as for computing equality of nodes (to be implemented later).
      */
-    public final int _nid;
+    public int _nid;
 
     /**
      * Inputs to the node. These are use-def references to Nodes.
@@ -32,7 +32,7 @@ public abstract class Node {
      * Ordering is required because e.g. "a/b" is different from "b/a".
      * The first input (offset 0) is often a {@link CFGNode} node.
      */
-    public final Ary<Node> _inputs;
+    public Ary<Node> _inputs;
 
     /**
      * Outputs reference Nodes that are not null and have this Node as an
@@ -43,7 +43,7 @@ public abstract class Node {
      * walked in either direction.  These outputs are typically used for
      * efficient optimizations but otherwise have no semantics meaning.
      */
-    public final Ary<Node> _outputs;
+    public Ary<Node> _outputs;
 
 
     /**
@@ -120,7 +120,7 @@ public abstract class Node {
             : _print1(sb, visited);
     }
     // Every Node implements this; a partial-line recursive print
-    abstract StringBuilder _print1(StringBuilder sb, BitSet visited);
+    abstract public StringBuilder _print1(StringBuilder sb, BitSet visited);
 
     public String p(int depth) { return IRPrinter.prettyPrint(this,depth); }
 
@@ -267,13 +267,24 @@ public abstract class Node {
         assert isDead();        // Really dead now
     }
 
+    // Preserve CFG use-ordering when killing
+    public void killOrdered() {
+        CFGNode cfg = cfg0();
+        cfg._outputs.remove(cfg._outputs.find(this));
+        _inputs.set(0,null);
+        kill();
+    }
+
+
     // Mostly used for asserts and printing.
     public boolean isDead() { return isUnused() && nIns()==0 && _type==null; }
 
     // Shortcuts to stop DCE mid-parse
     // Add bogus null use to keep node alive
+    @SuppressWarnings("unchecked")
     public <N extends Node> N keep() { addUse(null); return (N)this; }
     // Remove bogus null.
+    @SuppressWarnings("unchecked")
     public <N extends Node> N unkeep() { delUse(null); return (N)this; }
     // Test "keep" status
     public boolean iskeep() { return _outputs.find(null) != -1; }
@@ -297,9 +308,8 @@ public abstract class Node {
         kill();
     }
 
-    // Replace uses of `def` with `this`, and insert `this` immediately after
-    // `def` in the basic block.
-    public void insertAfter( Node def, boolean must ) {
+    // insert `this` immediately after `def` in the same basic block.
+    public void insertAfter( Node def ) {
         CFGNode cfg = def.cfg0();
         int i = cfg._outputs.find(def)+1;
         if( cfg instanceof CallEndNode ) {
@@ -312,19 +322,6 @@ public abstract class Node {
         while( cfg.out(i) instanceof PhiNode || cfg.out(i) instanceof CalleeSaveNode )  i++;
         cfg._outputs.insert(this,i);
         _inputs.set(0,cfg);
-        for( int j=def.nOuts()-1; j>=0; j-- ) {
-            // Can we avoid a split of a split?  'this' split is used by
-            // another split in the same block.
-            if( !must && def.out(j) instanceof SplitNode split && def.out(j).cfg0()==cfg &&
-                !split._kind.contains("self") )
-                continue;
-            Node use = def._outputs.del(j);
-            use.unlock();
-            int idx = use._inputs.find(def);
-            use._inputs.set(idx,this);
-            addUse(use);
-        }
-        if( nIns()>1 ) setDef(1,def);
     }
 
     // Insert this in front of use.in(uidx) with this, and insert this
@@ -334,6 +331,8 @@ public abstract class Node {
         int i;
         if( use instanceof PhiNode phi ) {
             cfg = phi.region().cfg(uidx);
+            if( cfg instanceof CProjNode && cfg.in(0) instanceof NeverNode nvr )
+                cfg = nvr.cfg0();
             i = cfg.nOuts()-1;
         } else {
             i = cfg._outputs.find(use);
@@ -345,7 +344,7 @@ public abstract class Node {
         use.setDefOrdered(uidx,this);
     }
 
-    public void setDefOrdered(int idx, Node def) {
+    public void setDefOrdered( int idx, Node def) {
         // If old is dying, remove from CFG ordered
         Node old = in(idx);
         if( old!=null && old.nOuts()==1 ) {
@@ -484,6 +483,7 @@ public abstract class Node {
         return old;
     }
 
+    @SuppressWarnings("unchecked")
     public <N extends Node> N init() { _type = compute(); return (N)this; }
 
     /**
@@ -546,17 +546,16 @@ public abstract class Node {
      * or output of this node, that is, it is at least one step away.  The node
      * being added must benefit from this node being peepholed.
      */
-    Node addDep( Node dep ) {
+    <N extends Node> N addDep( N dep ) {
         // Running peepholes during the big assert cannot have side effects
         // like adding dependencies.
-        if( CODE._midAssert ) return this;
-        if( dep == null ) return this;
-        if( _deps==null ) _deps = new Ary<>(Node.class);
-        if( _deps   .find(dep) != -1 ) return this; // Already on list
-        if( _inputs .find(dep) != -1 ) return this; // No need for deps on immediate neighbors
-        if( _outputs.find(dep) != -1 ) return this;
-        _deps.add(dep);
-        return this;
+        if( CODE._midAssert ) return dep;
+        if( dep._deps==null ) dep._deps = new Ary<>(Node.class);
+        if( dep._deps   .find(this) != -1 ) return dep; // Already on list
+        if( dep._inputs .find(this) != -1 ) return dep; // No need for deps on immediate neighbors
+        if( dep._outputs.find(this) != -1 ) return dep;
+        dep._deps.add(this);
+        return dep;
     }
 
     // Move the dependents onto a worklist, and clear for future dependents.
@@ -582,7 +581,7 @@ public abstract class Node {
     }
     // Subclasses add extra checks (such as ConstantNodes have same constant),
     // and can assume "this!=n" and has the same Java class.
-    boolean eq( Node n ) { return true; }
+    public boolean eq( Node n ) { return true; }
 
 
     // Cached hash.  If zero, then not computed AND this Node is NOT in the GVN
@@ -664,7 +663,7 @@ public abstract class Node {
     boolean allCons(Node dep) {
         for( int i=1; i<nIns(); i++ )
             if( !(in(i)._type.isConstant()) ) {
-                in(i).addDep(dep); // If in(i) becomes a constant later, will trigger some peephole
+                dep.addDep(in(i)); // If in(i) becomes a constant later, will trigger some peephole
                 return false;
             }
         return true;
@@ -676,6 +675,18 @@ public abstract class Node {
     // Does not need to be implemented in isCFG() nodes.
     Node copy(Node lhs, Node rhs) { throw Utils.TODO("Binary ops need to implement copy"); }
 
+    public Node copy() {
+        Node n;
+        try { n = (Node)clone(); }
+        catch( Exception e ) { throw new RuntimeException(e); }
+        n._nid = CODE.getUID(); // allocate unique dense ID
+        n._inputs  = new Ary<>(Node.class);
+        n._outputs = new Ary<>(Node.class);
+        n._deps = null;
+        n._hash = 0;
+        return n;
+    }
+
     // Report any post-optimize errors
     public Parser.ParseException err() { return null; }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/NotNode.java b/src/main/java/com/seaofnodes/simple/node/NotNode.java
index b454de66..0314841d 100644
--- a/src/main/java/com/seaofnodes/simple/node/NotNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/NotNode.java
@@ -12,7 +12,7 @@ public class NotNode extends Node {
     @Override public String glabel() { return "!"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("(!"), visited);
         return sb.append(")");
     }
diff --git a/src/main/java/com/seaofnodes/simple/node/ParmNode.java b/src/main/java/com/seaofnodes/simple/node/ParmNode.java
index 8d7c4205..9e11a129 100644
--- a/src/main/java/com/seaofnodes/simple/node/ParmNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ParmNode.java
@@ -22,7 +22,7 @@ public class ParmNode extends PhiNode {
     public FunNode fun() { return (FunNode)in(0); }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         if( "main".equals(fun()._name) && _label.equals("arg") )
             return sb.append("arg");
         sb.append("Parm_").append(_label).append("(");
diff --git a/src/main/java/com/seaofnodes/simple/node/PhiNode.java b/src/main/java/com/seaofnodes/simple/node/PhiNode.java
index 16f38d45..0579ecd0 100644
--- a/src/main/java/com/seaofnodes/simple/node/PhiNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/PhiNode.java
@@ -13,7 +13,7 @@ public class PhiNode extends Node {
     final Type _declaredType;
 
     public PhiNode(String label, Type declaredType, Node... inputs) { super(inputs); _label = label;  assert declaredType!=null; _declaredType = declaredType; }
-    public PhiNode(PhiNode phi, String label, Type declaredType) { super(phi); _label = label; _declaredType = declaredType; }
+    public PhiNode(PhiNode phi, String label, Type declaredType) { super(phi); _label = label; _type = _declaredType = declaredType; }
     public PhiNode(PhiNode phi) { super(phi); _label = phi._label; _declaredType = phi._declaredType;  }
 
     public PhiNode(RegionNode r, Node sample) {
@@ -29,7 +29,7 @@ public class PhiNode extends Node {
     @Override public String glabel() { return "&phi;_"+_label; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         if( !(region() instanceof RegionNode r) || r.inProgress() )
             sb.append("Z");
         sb.append("Phi(");
@@ -58,7 +58,7 @@ public class PhiNode extends Node {
         for (int i = 1; i < nIns(); i++)
             // If the region's control input is live, add this as a dependency
             // to the control because we can be peeped should it become dead.
-            if( r.in(i).addDep(this)._type != Type.XCONTROL )
+            if( addDep(r.in(i))._type != Type.XCONTROL )
                 t = t.meet(in(i)._type);
         return t;
     }
@@ -80,37 +80,15 @@ public class PhiNode extends Node {
             if( r.in(i)._type == Type.XCONTROL )
                 return null;
 
-        // Pull "down" a common data op.  One less op in the world.  One more
-        // Phi, but Phis do not make code.
-        //   Phi(op(A,B),op(Q,R),op(X,Y)) becomes
-        //     op(Phi(A,Q,X), Phi(B,R,Y)).
-        Node op = in(1);
-        if( !isMem() && op.nIns()==3 && op.in(0)==null && same_op() ) {
-            assert !(op instanceof CFGNode);
-            Node[] lhss = new Node[nIns()];
-            Node[] rhss = new Node[nIns()];
-            lhss[0] = rhss[0] = in(0); // Set Region
-            for( int i=1; i<nIns(); i++ ) {
-                lhss[i] = in(i).in(1);
-                rhss[i] = in(i).in(2);
-            }
-            Node phi_lhs = new PhiNode(_label, _declaredType,lhss).peephole();
-            Node phi_rhs = new PhiNode(_label, _declaredType,rhss).peephole();
-            Node down = op.copy(phi_lhs,phi_rhs);
-            // Test not running backwards, which can happen for e.g. And's
-            if( down.compute().isa(compute()) )
-                return down;
-            in(1).in(1).addDep(this);
-            in(1).in(2).addDep(this);
-            in(2).in(1).addDep(this);
-            in(2).in(2).addDep(this);
-            down.kill();
-        }
+        // Generic "pull down op"
+        Node progress;
+        if( same_op() && (progress = drop_same_op()) != null )
+            return progress;
 
         // If merging Phi(N, cast(N)) - we are losing the cast JOIN effects, so just remove.
         if( nIns()==3 ) {
-            if( in(1) instanceof CastNode cast && cast.in(1).addDep(this)==in(2) ) return in(2);
-            if( in(2) instanceof CastNode cast && cast.in(1).addDep(this)==in(1) ) return in(1);
+            if( in(1) instanceof CastNode cast && addDep(cast.in(1))==in(2) ) return in(2);
+            if( in(2) instanceof CastNode cast && addDep(cast.in(1))==in(1) ) return in(1);
         }
         // If merging a null-checked null and the checked value, just use the value.
         // if( val ) ..; phi(Region,False=0/null,True=val);
@@ -123,7 +101,7 @@ public class PhiNode extends Node {
                 Node val = in(3-nullx);
                 if( val instanceof CastNode cast )
                     val = cast.in(1);
-                if( r.idom(this).addDep(this) instanceof IfNode iff && iff.pred().addDep(this)==val ) {
+                if( addDep(r.idom(this)) instanceof IfNode iff && addDep(iff.pred())==val ) {
                     // Must walk the idom on the null side to make sure we hit False.
                     CFGNode idom = (CFGNode)r.in(nullx);
                     while( idom != null && idom.nIns() > 0 && idom.in(0) != iff ) idom = idom.idom();
@@ -136,13 +114,52 @@ public class PhiNode extends Node {
         return null;
     }
 
+    // Same op on all Phi paths; all ops have only the Phi as a use.
+    // None have a control input.
     private boolean same_op() {
-        for( int i=2; i<nIns(); i++ )
-            if( in(1).getClass() != in(i).getClass() )
+        for( int i=1; i<nIns(); i++ ) {
+            Node op = in(i);
+            if( in(1).getClass() != op.getClass() || op.in(0)!=null || in(1).nIns() != op.nIns() )
+                return false;      // Wrong class or CFG bound or mismatched inputs
+            if( op.nOuts() > 1 ) { // Too many users, but addDep in case lose users
+                for( Node out : op._outputs )
+                    if( out!=null && out!=this )
+                        addDep(out);
                 return false;
+            }
+        }
         return true;
     }
 
+    private Node drop_same_op() {
+        assert !(in(1) instanceof CFGNode);
+        Node op = in(1);
+        Node cp = op.copy();
+        cp._type = null;    // Fresh type
+        cp.addDef(null);    // No control
+
+        for( int j=1; j<op.nIns(); j++ ) {
+            boolean needsPhi = false;
+            Node x = op.in(j); // Jth input from sample #1
+            for( int i=2; i<nIns(); i++ )
+                if( in(i).in(j) != x )
+                    { needsPhi=true; break; }
+            if( needsPhi ) {
+                x = new PhiNode(_label,op.in(j)._type.glb());
+                x.addDef(region());
+                for( int i=1; i<nIns(); i++ )
+                    x.addDef(in(i).in(j));
+                x = x.peephole();
+            }
+            cp.addDef(x);
+        }
+        // Test not running backwards, which can happen for e.g. And's
+        if( cp.compute().isa(compute()) )
+            return cp;
+        cp.kill();
+        return null;
+    }
+
     /**
      * If only single unique input, return it
      */
@@ -153,7 +170,7 @@ public class PhiNode extends Node {
         for( int i=1; i<nIns(); i++ ) {
             // If the region's control input is live, add this as a dependency
             // to the control because we can be peeped should it become dead.
-            if( region().in(i).addDep(this)._type != Type.XCONTROL && in(i) != this )
+            if( addDep(region().in(i))._type != Type.XCONTROL && in(i) != this )
                 if( live == null || live == in(i) ) live = in(i);
                 else return null;
         }
@@ -165,7 +182,7 @@ public class PhiNode extends Node {
         if( !(region() instanceof RegionNode r) ) return false;
         // When the region completes (is no longer in progress) the Phi can
         // become a "all constants" Phi, and the "dep" might make progress.
-        addDep(dep);
+        dep.addDep(this);
         if( r.inProgress() ) return false;
         return super.allCons(dep);
     }
@@ -176,7 +193,7 @@ public class PhiNode extends Node {
     }
 
     // Never equal if inProgress
-    @Override boolean eq( Node n ) {
+    @Override public boolean eq( Node n ) {
         return !inProgress();
     }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/ProjNode.java b/src/main/java/com/seaofnodes/simple/node/ProjNode.java
index 3d9db4ed..a0394e5b 100644
--- a/src/main/java/com/seaofnodes/simple/node/ProjNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ProjNode.java
@@ -24,7 +24,7 @@ public class ProjNode extends Node {
     @Override public String label() { return _label; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         if( _label != null )  return sb.append(_label);
         if( in(0) instanceof CallEndNode cend && cend.call()!=null )
             return cend.call()._print0(sb,visited);
@@ -47,7 +47,7 @@ public class ProjNode extends Node {
     @Override public Node idealize() { return ((MultiNode)in(0)).pcopy(_idx); }
 
     @Override
-    boolean eq( Node n ) { return _idx == ((ProjNode)n)._idx; }
+    public boolean eq( Node n ) { return _idx == ((ProjNode)n)._idx; }
 
     @Override
     int hash() { return _idx; }
diff --git a/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java b/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java
index b755af3f..e9c25f47 100644
--- a/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java
@@ -14,7 +14,7 @@ public class ReadOnlyNode extends Node {
     @Override public String label() { return "ReadOnly"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         return in(1)._print0(sb.append("(const)"),visited);
     }
     @Override public Type compute() {
diff --git a/src/main/java/com/seaofnodes/simple/node/RegionNode.java b/src/main/java/com/seaofnodes/simple/node/RegionNode.java
index fb6539ae..8f65d0e5 100644
--- a/src/main/java/com/seaofnodes/simple/node/RegionNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/RegionNode.java
@@ -1,6 +1,7 @@
 package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.type.Type;
 import java.util.*;
@@ -17,7 +18,7 @@ public class RegionNode extends CFGNode {
     public String label() { return "Region"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         return sb.append(label());
     }
 
@@ -47,7 +48,7 @@ public class RegionNode extends CFGNode {
         if( !hasPhi() &&         // No Phi users, just a control user
             in(1) instanceof CProjNode p1 &&
             in(2) instanceof CProjNode p2 &&
-            p1.in(0).addDep(this)==p2.in(0).addDep(this) &&
+            addDep(p1.in(0))==addDep(p2.in(0)) &&
             p1.in(0) instanceof IfNode iff ) {
             // Replace with the iff.ctrl directly
             if( nIns()==3 ) return iff.ctrl();
@@ -56,6 +57,29 @@ public class RegionNode extends CFGNode {
             return delDef(2);
         }
 
+        // Flatten stack regions (no loops involved)
+        if( getClass() == RegionNode.class ) {
+            for( int i=1; i<nIns(); i++ )
+                if( cfg(i) instanceof RegionNode region && region.getClass() == RegionNode.class && region.nIns()>2 && !hasMidUser(region) ) {
+                    assert !region.inProgress();
+                    // Fold Phis
+                    for( Node use : _outputs ) {
+                        if( use instanceof PhiNode phi ) {
+                            PhiNode phi2 = phi.in(i) instanceof PhiNode phi2x && phi2x.region()==region ? phi2x : null;
+                            for( int j=1; j<region.nIns(); j++ )
+                                phi.addDef(phi2==null ? phi.in(i) : phi2.in(j));
+                            CodeGen.CODE.add(phi);
+                        }
+                    }
+
+                    // Fold Region
+                    for( int j=1; j<region.nIns(); j++ )
+                        addDef(region.in(j));
+                    setDef(i,Parser.XCTRL);
+                    return this;
+                }
+        }
+
         return null;
     }
 
@@ -98,14 +122,32 @@ public class RegionNode extends CFGNode {
         return false;
     }
 
+    // Is there a value in-between 2 Regions?  Difficult to correctly fuse
+    // without extensive testing, so just ignore.
+    boolean hasMidUser(RegionNode r) {
+        for( Node use : r._outputs ) {
+            if( use==this ) continue;
+            if( use instanceof PhiNode ) {
+                for( Node data : use._outputs ) {
+                    if( !(data instanceof PhiNode phi2) || phi2.region()!=this )
+                        { addDep(use); addDep(data); return true; }
+                }
+            } else
+                { addDep(use);  return true; } // Control user
+        }
+        return false;
+    }
+
+
     // Immediate dominator of Region is a little more complicated.
     @Override public int idepth() {
-        if( _idepth!=0 ) return _idepth;
+        if( CodeGen.CODE.validIDepth(_idepth) )
+            return _idepth;
         int d=0;
         for( Node n : _inputs )
             if( n!=null )
-                d = Math.max(d,((CFGNode)n).idepth()+1);
-        return _idepth=d;
+                d = Math.max(d,CodeGen.CODE.iDepthFrom(((CFGNode)n).idepth()));
+        return _idepth = d;
     }
 
     @Override public CFGNode idom(Node dep) {
@@ -121,6 +163,6 @@ public class RegionNode extends CFGNode {
     public boolean inProgress() { return nIns()>1 && in(nIns()-1) == null; }
 
     // Never equal if inProgress
-    @Override boolean eq( Node n ) { return !inProgress(); }
+    @Override public boolean eq( Node n ) { return !inProgress(); }
 
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/ReturnNode.java b/src/main/java/com/seaofnodes/simple/node/ReturnNode.java
index 809dd1e1..317f4ce8 100644
--- a/src/main/java/com/seaofnodes/simple/node/ReturnNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ReturnNode.java
@@ -3,6 +3,9 @@ package com.seaofnodes.simple.node;
 import com.seaofnodes.simple.Parser;
 import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.type.*;
 import java.util.BitSet;
 
@@ -29,13 +32,13 @@ public class ReturnNode extends CFGNode {
     public Node mem () { return in(1); }
     public Node expr() { return in(2); }
     public Node rpc () { return in(3); }
-    public FunNode fun() { return _fun; }
+    @Override public FunNode fun() { return _fun; }
 
     @Override
     public String label() { return "Return"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         sb.append("return ");
         if( expr()==null ) sb.append("----");
         else expr()._print0(sb, visited);
@@ -127,4 +130,39 @@ public class ReturnNode extends CFGNode {
         if( tp || tn ) sb.p("reference and ");
         return Parser.error(sb.unchar(5).toString(),loc);
     }
+
+
+    // ------------
+    // MachNode specifics, shared across all CPUs
+    public String op() {
+        return _fun._frameAdjust > 0 ? "addi" : "ret";
+    }
+    // Correct Nodes outside the normal edges
+    public void postSelect(CodeGen code) {
+        FunNode fun = (FunNode)rpc().in(0);
+        _fun = fun;
+        fun.setRet(this);
+    }
+    public RegMask regmap(int i) {
+        return i==2
+            ? CodeGen.CODE._mach.retMask(_fun.sig())
+            : CodeGen.CODE._retMasks[i];
+    }
+    public RegMask outregmap() { return null; }
+    public void encoding( Encoding enc ) { throw Utils.TODO(); }
+    public void asm(CodeGen code, SB sb) {
+        int frameAdjust = fun()._frameAdjust;
+        if( frameAdjust>0 )
+            sb.p("rsp += #").p(frameAdjust).p("\nret");
+        // Post code-gen, just print the "ret"
+        if( code._phase.ordinal() <= CodeGen.Phase.RegAlloc.ordinal() )
+            // Prints return reg (either RAX or XMM0), RPC and then the
+            // callee-save registers.
+            for( int i=2; i<nIns(); i++ )
+                sb.p(code.reg(in(i),fun())).p("  ");
+        // If we did not get the expected rpc, print which one we got
+        else if( code._regAlloc.regnum(rpc()) != code._mach.rpc() )
+            sb.p("[").p(code.reg(rpc())).p("]");
+    }
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java b/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java
index 44d3a587..7936086d 100644
--- a/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java
+++ b/src/main/java/com/seaofnodes/simple/node/RoundF32Node.java
@@ -13,7 +13,7 @@ public class RoundF32Node extends Node {
     @Override public String glabel() { return "(f32)"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         return in(1)._print0(sb.append("((f32)"), visited).append(")");
     }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/ScopeNode.java b/src/main/java/com/seaofnodes/simple/node/ScopeNode.java
index f193e55a..38a5d968 100644
--- a/src/main/java/com/seaofnodes/simple/node/ScopeNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ScopeNode.java
@@ -44,7 +44,7 @@ public class ScopeNode extends MemMergeNode {
     @Override public String label() { return "Scope"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         sb.append("Scope[ ");
         int j=1;
         for( int i=0; i<nIns(); i++ ) {
diff --git a/src/main/java/com/seaofnodes/simple/node/ShlNode.java b/src/main/java/com/seaofnodes/simple/node/ShlNode.java
index 21dbd503..82e01841 100644
--- a/src/main/java/com/seaofnodes/simple/node/ShlNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ShlNode.java
@@ -38,7 +38,7 @@ public class ShlNode extends LogicalNode {
             if( (shl.value()&63)==0 )
                 return lhs;
             // (x + c) << i  =>  (x << i) + (c << i)
-            if( lhs instanceof AddNode add && add.addDep(this).in(2)._type instanceof TypeInteger c && c.isConstant() ) {
+            if( lhs instanceof AddNode add && addDep(add).in(2)._type instanceof TypeInteger c && c.isConstant() ) {
                 long sum = c.value() << shl.value();
                 if( Integer.MIN_VALUE <= sum  && sum <= Integer.MAX_VALUE )
                     return new AddNode(new ShlNode(_loc,add.in(1),rhs).peephole(), Parser.con(sum) );
diff --git a/src/main/java/com/seaofnodes/simple/node/SplitNode.java b/src/main/java/com/seaofnodes/simple/node/SplitNode.java
index 22cb9bb9..3a1ed011 100644
--- a/src/main/java/com/seaofnodes/simple/node/SplitNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/SplitNode.java
@@ -11,7 +11,10 @@ public abstract class SplitNode extends MachConcreteNode {
     public SplitNode(String kind, byte round, Node[] nodes) { super(nodes); _kind = kind; _round = round; }
     @Override public String op() { return "mov"; }
     @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) {
-        return in(1)._print0(sb.append("mov("),visited).append(")");
+        sb.append("mov(");
+        if( in(1) == null ) sb.append("---");
+        else in(1)._print0(sb,visited);
+        return sb.append(")");
     }
     @Override public Type compute() { return in(0)._type; }
     @Override public Node idealize() { return null; }
diff --git a/src/main/java/com/seaofnodes/simple/node/StartNode.java b/src/main/java/com/seaofnodes/simple/node/StartNode.java
index 22a1750d..f40203b4 100644
--- a/src/main/java/com/seaofnodes/simple/node/StartNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/StartNode.java
@@ -25,7 +25,7 @@ public class StartNode extends LoopNode implements MultiNode {
     @Override public String label() { return "Start"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
       return sb.append(label());
     }
 
@@ -51,7 +51,7 @@ public class StartNode extends LoopNode implements MultiNode {
     @Override public Node idealize() { return null; }
 
     // No immediate dominator, and idepth==0
-    @Override public int idepth() { return 0; }
+    @Override public int idepth() { return CodeGen.CODE.iDepthAt(0); }
     @Override public CFGNode idom(Node dep) { return null; }
 
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/StopNode.java b/src/main/java/com/seaofnodes/simple/node/StopNode.java
index b4cb002b..9be08ad9 100644
--- a/src/main/java/com/seaofnodes/simple/node/StopNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/StopNode.java
@@ -21,12 +21,13 @@ public class StopNode extends CFGNode {
     }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         // For the sake of many old tests, and single value prints as "return val"
         if( ret()!=null ) return ret()._print0(sb,visited);
         sb.append("Stop[ ");
         for( Node ret : _inputs )
-            ret._print0(sb, visited).append(" ");
+            if( ret!=null )
+                ret._print0(sb, visited).append(" ");
         return sb.append("]");
     }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/StoreNode.java b/src/main/java/com/seaofnodes/simple/node/StoreNode.java
index 93294dba..a6992f04 100644
--- a/src/main/java/com/seaofnodes/simple/node/StoreNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/StoreNode.java
@@ -20,7 +20,7 @@ public class StoreNode extends MemOpNode {
      * @param value Value to be stored
      */
     public StoreNode(Parser.Lexer loc, String name, int alias, Type glb, Node mem, Node ptr, Node off, Node value, boolean init) {
-        super(loc, name, alias, glb, mem, ptr, off, value);
+        super(loc, name, alias, false, glb, mem, ptr, off, value);
         _init = init;
     }
 
@@ -33,7 +33,7 @@ public class StoreNode extends MemOpNode {
     public Node val() { return in(4); }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         return sb.append(".").append(_name).append("=").append( val()).append(";");
     }
 
@@ -84,6 +84,11 @@ public class StoreNode extends MemOpNode {
             }
         }
 
+        // Store of zero after alloc
+        if( mem() instanceof ProjNode prj && prj.in(0) instanceof NewNode &&
+            prj.in(0)==ptr().in(0) &&  // Same NewNode memory & pointer
+            (val()._type==TypeInteger.ZERO || val()._type==Type.NIL ) )
+            return mem();
 
         return null;
     }
@@ -95,7 +100,7 @@ public class StoreNode extends MemOpNode {
         // when the other uses go away we can retry.
         for( Node use : mem._outputs )
             if( use != this )
-                use.addDep(this);
+                addDep(use);
         return false;
     }
 
@@ -106,7 +111,7 @@ public class StoreNode extends MemOpNode {
         TypeMemPtr tmp = (TypeMemPtr)ptr()._type;
         if( tmp._obj.field(_name)._final && !_init )
             return Parser.error("Cannot modify final field '"+_name+"'",_loc);
-        Type t = val()._type;
+        //Type t = val()._type;
         //return _init || t.isa(_declaredType) ? null : Parser.error("Cannot store "+t+" into field "+_declaredType+" "+_name,_loc);
         return null;
     }
diff --git a/src/main/java/com/seaofnodes/simple/node/StructNode.java b/src/main/java/com/seaofnodes/simple/node/StructNode.java
index 076b342a..4efc0de9 100644
--- a/src/main/java/com/seaofnodes/simple/node/StructNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/StructNode.java
@@ -14,7 +14,7 @@ public class StructNode extends Node {
     @Override public String label() { return _ts==null ? "STRUCT?" : _ts.str(); }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         if( _ts==null ) return sb.append("STRUCT?");
         sb.append(_ts._name).append(" {");
         for( int i=0; i<nIns(); i++ ) {
@@ -39,7 +39,7 @@ public class StructNode extends Node {
     public Node idealize() { return null; }
 
     @Override
-    boolean eq(Node n) { return _ts == ((StructNode)n)._ts; }
+    public boolean eq(Node n) { return _ts == ((StructNode)n)._ts; }
 
     @Override
     int hash() { return _ts==null ? 0 : _ts.hashCode(); }
diff --git a/src/main/java/com/seaofnodes/simple/node/SubFNode.java b/src/main/java/com/seaofnodes/simple/node/SubFNode.java
index b591718d..5c7e969f 100644
--- a/src/main/java/com/seaofnodes/simple/node/SubFNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/SubFNode.java
@@ -13,7 +13,7 @@ public class SubFNode extends Node {
     @Override public String glabel() { return "-"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("("), visited);
         in(2)._print0(sb.append("-"), visited);
         return sb.append(")");
diff --git a/src/main/java/com/seaofnodes/simple/node/SubNode.java b/src/main/java/com/seaofnodes/simple/node/SubNode.java
index 339c65ca..4290ff9b 100644
--- a/src/main/java/com/seaofnodes/simple/node/SubNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/SubNode.java
@@ -13,7 +13,7 @@ public class SubNode extends Node {
     @Override public String glabel() { return "-"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         in(1)._print0(sb.append("("), visited);
         in(2)._print0(sb.append("-"), visited);
         return sb.append(")");
diff --git a/src/main/java/com/seaofnodes/simple/node/ToFloatNode.java b/src/main/java/com/seaofnodes/simple/node/ToFloatNode.java
index 1f4d67e0..c098ad99 100644
--- a/src/main/java/com/seaofnodes/simple/node/ToFloatNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/ToFloatNode.java
@@ -14,7 +14,7 @@ public class ToFloatNode extends Node {
     @Override public String glabel() { return "(flt)"; }
 
     @Override
-    StringBuilder _print1(StringBuilder sb, BitSet visited) {
+    public StringBuilder _print1(StringBuilder sb, BitSet visited) {
         return in(1)._print0(sb.append("(flt)"), visited);
     }
 
diff --git a/src/main/java/com/seaofnodes/simple/node/XCtrlNode.java b/src/main/java/com/seaofnodes/simple/node/XCtrlNode.java
index da021246..8c620a04 100644
--- a/src/main/java/com/seaofnodes/simple/node/XCtrlNode.java
+++ b/src/main/java/com/seaofnodes/simple/node/XCtrlNode.java
@@ -8,7 +8,7 @@ import java.util.BitSet;
 public class XCtrlNode extends CFGNode {
     public XCtrlNode() { super(new Node[]{CodeGen.CODE._start}); }
     @Override public String label() { return "Xctrl"; }
-    @Override StringBuilder _print1(StringBuilder sb, BitSet visited) { return sb.append("Xctrl"); }
+    @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) { return sb.append("Xctrl"); }
     @Override public boolean isConst() { return true; }
     @Override  public Type compute() { return Type.XCONTROL; }
     @Override public Node idealize() { return null; }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/AddARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/AddARM.java
index c4014571..f37738bf 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/AddARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/AddARM.java
@@ -1,34 +1,20 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class AddARM extends MachConcreteNode implements MachNode {
+    AddARM( Node add) { super(add); }
+    @Override public String op() { return "add"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
 
-    AddARM( Node add) {super(add); }
-
-    // Register mask allowed on input i.
-    @Override public RegMask regmap(int i) {
-        assert i== 1 || i == 2 || i == 3;
-        return arm.RMASK;
-    }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
+    // ADD (shifted register)
+    @Override public void encoding( Encoding enc ) { arm.r_reg(enc,this,arm.OP_ADD); }
     // General form: "rd = rs1 + rs2"
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" + ").p(code.reg(in(2)));
     }
 
-    @Override public String op() {
-        return "add";}
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/AddFARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/AddFARM.java
index 098ab8c1..209f24f4 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/AddFARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/AddFARM.java
@@ -1,31 +1,22 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class AddFARM extends MachConcreteNode implements MachNode {
     AddFARM(Node addf) { super(addf); }
-
-    // Register mask allowed on input i.
-    @Override public RegMask regmap(int i) { assert i==1 || i==2; return arm.DMASK; }
-    // Register mask allowed as a result.  0 for no register.
+    @Override public String op() { return "addf"; }
+    @Override public RegMask regmap(int i) { return arm.DMASK; }
     @Override public RegMask outregmap() { return arm.DMASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
+    //FADD (scalar)
+    @Override public void encoding( Encoding enc ) { arm.f_scalar(enc,this,arm.OPF_OP_ADD);}
 
     // Default on double precision for now(64 bits)
-    // General form: "vadd.32  rd = src1 + src2
+    // General form: "addf  rd = src1 + src2
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" + ").p(code.reg(in(2)));
     }
 
-    @Override public String op() { return "addf"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/AddIARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/AddIARM.java
index c8f5f8dd..a1cd8306 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/AddIARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/AddIARM.java
@@ -1,51 +1,27 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class AddIARM extends MachConcreteNode implements MachNode {
-    final TypeInteger _ti;
-
-    AddIARM(Node add, TypeInteger ti) {
+    final int _imm;
+    AddIARM(Node add, int imm) {
         super(add);
         _inputs.pop();
-        _ti = ti;
+        _imm = imm;
     }
-
-    // Register mask allowed on input i.
-    @Override
-    public RegMask regmap(int i) {
-        // assert i== i;
-        return arm.RMASK;
+    @Override public String op() {
+        return _imm == 1 ? "inc" : (_imm == -1 ? "dec" : "addi");
     }
-
-    // Register mask allowed as a result.  0 for no register.
-    @Override
-    public RegMask outregmap() {
-        return arm.RMASK;
-    }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override
-    public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
+    //ADD (immediate)
+    @Override public void encoding( Encoding enc ) {
+        arm.imm_inst(enc,this, in(1), arm.OPI_ADD,_imm);
     }
-
     // General form: "addi  rd = rs1 + imm"
-    @Override
-    public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" + #");
-        _ti.print(sb);
+    @Override public void asm(CodeGen code, SB sb) {
+        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" + #").p(_imm);
     }
-
-    @Override
-    public String op() {
-        return _ti.value() == 1 ? "inc" : (_ti.value() == -1 ? "dec" : "addi");
-
-    }
-
-}
\ No newline at end of file
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/AndARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/AndARM.java
index 7655df40..ad76ca4c 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/AndARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/AndARM.java
@@ -1,36 +1,19 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.MachConcreteNode;
 import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.node.Node;
 
-import java.io.ByteArrayOutputStream;
-
 public class AndARM extends MachConcreteNode implements MachNode {
-    AndARM(Node and) {
-        super(and);
-    }
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        assert i==1 || i==2;
-        return arm.RMASK;
-    }
-
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
+    AndARM(Node and) { super(and); }
+    @Override public String op() { return "and"; }
+    @Override public String glabel() { return "&"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
+    // AND (shifted register)
+    @Override public void encoding( Encoding enc ) { arm.r_reg(enc,this,arm.OP_AND); }
     // General form:  #rd = rs1 & rs2
     @Override public void asm(CodeGen code, SB sb){
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" & ").p(code.reg(in(2)));
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/AndIARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/AndIARM.java
index ee05654b..1f12ef13 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/AndIARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/AndIARM.java
@@ -1,56 +1,24 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
-import java.lang.StringBuilder;
-
-public class AndIARM  extends MachConcreteNode implements MachNode {
-    final TypeInteger _ti;
 
-    AndIARM(AndNode and, TypeInteger ti) {
+public class AndIARM extends MachConcreteNode implements MachNode {
+    final int _imm;
+    AndIARM(Node and, int imm) {
         super(and);
         _inputs.pop();
-        _ti = ti;
-    }
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override
-    public RegMask regmap(int i) {
-        assert i == 1 || i == 2;
-        return arm.RMASK;
+        _imm = imm;
     }
-
-    // Register mask allowed as a result.  0 for no register.
-    @Override
-    public RegMask outregmap() {
-        return arm.RMASK;
+    @Override public String op() { return "andi"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
+    @Override public void encoding( Encoding enc ) {
+        arm.imm_inst_n(enc,this, in(1), arm.OPI_AND,_imm);
     }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override
-    public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
     // General form: "andi  rd = rs1 & imm"
-    @Override
-    public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" & #");
-        _ti.print(sb);
+    @Override public void asm(CodeGen code, SB sb) {
+        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" & #").p(arm.decodeImm12(_imm));
     }
-
-    @Override
-    public String op() {
-        return "andi";
-    }
-
 }
\ No newline at end of file
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/AsrARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/AsrARM.java
index a79de49b..342b7519 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/AsrARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/AsrARM.java
@@ -1,40 +1,18 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
-import java.lang.StringBuilder;
 
 // Arithmetic Shift Right (register)
 public class AsrARM extends MachConcreteNode implements MachNode {
     AsrARM(Node asr) {super(asr);}
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        // assert i==1;
-        return arm.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form: "asr rd, rs1, rs2"
+    @Override public String op() { return "sar"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.DMASK; }
+    @Override public void encoding( Encoding enc ) { arm.shift_reg(enc,this,arm.OP_ASR); }
     @Override public void asm(CodeGen code, SB sb) {
-
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" >> ").p(code.reg(in(2)));
     }
 
-    @Override public String op() { return "asr"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/AsrIARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/AsrIARM.java
index 099c3699..a1775dde 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/AsrIARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/AsrIARM.java
@@ -1,41 +1,31 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-
-import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
-import java.lang.StringBuilder;
+import com.seaofnodes.simple.node.MachConcreteNode;
+import com.seaofnodes.simple.node.MachNode;
+import com.seaofnodes.simple.node.Node;
 
-// Arithmetic Shift Right (immediate)
 public class AsrIARM extends MachConcreteNode implements MachNode {
-    final TypeInteger _ti;
-    AsrIARM(Node asri, TypeInteger ti) {super(asri); _inputs.pop();  _ti = ti;}
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        // assert i==1;
-        return arm.RMASK; }
-
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    final int _imm;
+    AsrIARM(Node asr, int imm) {
+        super(asr);
+        _inputs.pop();
+        _imm = imm;
     }
-
-    // General form
-    // General form: "asri rd, rs1, imm"
+    @Override public String op() { return "asri"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
+    @Override public void encoding( Encoding enc ) {
+        short rd = enc.reg(this);
+        short rn = enc.reg(in(1));
+        assert _imm > 0;
+        enc.add4(arm.imm_shift(arm.OPI_ASR,_imm, 0b111111, rn, rd));
+    }
+    // General form: "asri  rd = rs1 >> imm"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" >> #");
-        _ti.print(sb);
+        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" >> #").p(_imm);
     }
-
-    @Override public String op() { return "asri"; }
-}
+}
\ No newline at end of file
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/BranchARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/BranchARM.java
index 1a5108cf..b36a395b 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/BranchARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/BranchARM.java
@@ -1,25 +1,22 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 
-import java.io.ByteArrayOutputStream;
-
-
 // Jump on flags, uses flags
-public class BranchARM extends IfNode implements MachNode{
-    final String _bop;
+public class BranchARM extends IfNode implements MachNode, RIPRelSize {
+    String _bop;
     BranchARM(IfNode iff, String bop ) {
         super(iff);
         _bop = bop;
     }
-
+    @Override public String op() { return "j"+_bop; }
     @Override public String label() { return op(); }
 
-    @Override public void postSelect() {
+    @Override public void postSelect(CodeGen code) {
         Node set = in(1);
+        if( set==null ) return; // Never-node cutout
         Node cmp = set.in(1);
         // Bypass an expected Set and just reference the cmp directly
         if( set instanceof SetARM)
@@ -30,19 +27,50 @@ public class BranchARM extends IfNode implements MachNode{
 
     @Override public RegMask regmap(int i) { assert i==1; return arm.FLAGS_MASK; }
     @Override public RegMask outregmap() { return null; }
+    @Override public void negate() { _bop = negate(_bop);  }
+
+    @Override public void encoding( Encoding enc ) {
+        // Assuming that condition flags are already set.  These flags are set
+        // by comparison (or sub).  No need for regs because it uses flags
+        if( in(1)!=null ) {
+            // B.cond
+            enc.add4( arm.b_cond(arm.OP_BRANCH, 0, arm.make_condition(_bop)) );
+        } else {
+            if( _bop=="!=" ) return; // Inverted, no code
+            enc.add4(arm.b(arm.OP_UJMP, 0));
+        }
+        enc.jump(this,cproj(0));
+    }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
+    // Delta is from opcode start
+    @Override public byte encSize(int delta) {
+        if( in(1)==null && _bop=="!=" ) return 0; // Inverted never-node, no code
+        if( -(1<<19) <= delta && delta < (1<<19) ) return 4;
+        // 2 word encoding needs a tmp register, must teach RA
         throw Utils.TODO();
     }
 
-    @Override public void asm(CodeGen code, SB sb) {
-        String src = code.reg(in(1));
-        if( src!="flags" )  sb.p(src);
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        assert !( in(1)==null && _bop=="!=" ); // Inverted never-node, no code no patch
+        if( opLen==4 ) {
+            enc.patch4(opStart,arm.b_cond(arm.OP_BRANCH, delta, arm.make_condition(_bop)));
+        } else {
+            throw Utils.TODO();
+        }
     }
 
-    @Override public String op() { return "j"+_bop; }
-    @Override public String comment() {
-        return "L"+cproj(1)._nid+", L"+cproj(0)._nid;
+    @Override public void asm(CodeGen code, SB sb) {
+        if( in(1)!=null ) {     // Never-node
+            String src = code.reg(in(1));
+            if( src!="flags" ) sb.p(src).p(" ");
+        } else if( _bop=="!=" ) {
+            sb.p("never");
+            return;
+        }
+        CFGNode prj = cproj(0).uctrlSkipEmpty();
+        if( !prj.blockHead() ) prj = prj.cfg0();
+        sb.p(label(prj));
     }
+    @Override public String comment() { return "L"+cproj(1)._nid; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallARM.java
index 4359c045..7f6fe93c 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallARM.java
@@ -1,13 +1,11 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.TypeFunPtr;
-import java.io.ByteArrayOutputStream;
 
-public class CallARM extends CallNode implements MachNode {
+public class CallARM extends CallNode implements MachNode, RIPRelSize {
     final TypeFunPtr _tfp;
     final String _name;
 
@@ -19,27 +17,31 @@ public class CallARM extends CallNode implements MachNode {
         _name = CodeGen.CODE.link(tfp)._name;
     }
 
+    @Override public String op() { return "call"; }
     @Override public String label() { return op(); }
-    @Override public RegMask regmap(int i) {
-        return arm.callInMask(_tfp,i); // Normal argument
-    }
-    @Override public RegMask outregmap() { return null; }
-
     @Override public String name() { return _name; }
     @Override public TypeFunPtr tfp() { return _tfp; }
+    @Override public RegMask regmap(int i) { return arm.callInMask(_tfp,i,fun()._maxArgSlot); }
+    @Override public RegMask outregmap() { return null; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        enc.relo(this);
+        // BL
+        enc.add4(arm.b(arm.OP_CALL,0)); // Target patched at link time
+    }
+
+    // Delta is from opcode start, but X86 measures from the end of the 5-byte encoding
+    @Override public byte encSize(int delta) { return 4; }
+
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        enc.patch4(opStart,arm.b(arm.OP_CALL,delta));
     }
 
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(_name);
         for( int i=0; i<nargs(); i++ )
-            sb.p(code.reg(arg(i))).p("  ");
+            sb.p(code.reg(arg(i+2))).p("  ");
         sb.unchar(2);
     }
-
-    @Override public String op() { return "call"; }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallEndARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallEndARM.java
index 6177c5ea..b3c2f6c2 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallEndARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallEndARM.java
@@ -1,35 +1,8 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.node.CallEndNode;
 import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.type.TypeFloat;
-import com.seaofnodes.simple.type.TypeFunPtr;
-import java.io.ByteArrayOutputStream;
 
 public class CallEndARM extends CallEndNode implements MachNode {
-    final TypeFunPtr _tfp;
-    CallEndARM( CallEndNode cend ) {
-        super(cend);
-        _tfp = (TypeFunPtr)(cend.call().fptr()._type);
-    }
-
-    @Override public String label() { return op(); }
-    @Override public RegMask regmap(int i) { return null; }
-    @Override public RegMask outregmap() { return null; }
-    @Override public RegMask outregmap(int idx) { return idx == 2 ? arm.retMask(_tfp,2) : null; }
-    @Override public RegMask killmap() { return arm.armCallerSave(); }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    @Override public void asm(CodeGen code, SB sb) {  }
-
-    @Override public String op() { return "cend"; }
-
+    CallEndARM( CallEndNode cend ) { super(cend); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallRRARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallRRARM.java
index db85a9a9..87dde38c 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallRRARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallRRARM.java
@@ -1,26 +1,25 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import java.io.ByteArrayOutputStream;
 
 public class CallRRARM extends CallNode implements MachNode {
-    CallRRARM(CallNode call) {super(call);}
+    CallRRARM(CallNode call) { super(call); }
     @Override public String op() { return "callr"; }
     @Override public String label() { return op(); }
     @Override public RegMask regmap(int i) {
-        // Todo: float or int?
         return i==_inputs._len
             ? arm.RMASK                // Function call target
-            : arm.callInMask(tfp(),i); // Normal argument
+            : arm.callInMask(tfp(),i,fun()._maxArgSlot); // Normal argument
     }
     @Override public RegMask outregmap() { return null; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        // Needs a register, typically a jump-and-link-register opcode
+        // blr
+        short self = enc.reg(this);
+        enc.add4(arm.blr(arm.OP_CALLRARM, self));
     }
 
     @Override public void asm(CodeGen code, SB sb) {
@@ -29,4 +28,5 @@ public class CallRRARM extends CallNode implements MachNode {
             sb.p(code.reg(arg(i))).p("  ");
         sb.unchar(2);
     }
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CastARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CastARM.java
new file mode 100644
index 00000000..a5a4e112
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CastARM.java
@@ -0,0 +1,18 @@
+package com.seaofnodes.simple.node.cpus.arm;
+
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
+import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.node.CastNode;
+import com.seaofnodes.simple.node.MachNode;
+
+public class CastARM extends CastNode implements MachNode {
+    public CastARM( CastNode cast ) { super(cast); }
+    @Override public String op() { return label(); }
+    @Override public RegMask regmap(int i) { assert i==1; return RegMask.FULL; }
+    @Override public RegMask outregmap() { return RegMask.FULL; }
+    @Override public int twoAddress( ) { return 1; }
+    @Override public void encoding( Encoding enc ) { }
+    @Override public void asm(CodeGen code, SB sb) { _t.print(sb.p(code.reg(in(1))).p(" isa ")); }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpARM.java
index f4f6242d..dbc86f62 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpARM.java
@@ -1,25 +1,17 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFunPtr;
-import java.io.ByteArrayOutputStream;
 
 public class CmpARM extends MachConcreteNode implements MachNode {
     CmpARM( Node cmp ) { super(cmp); }
     @Override public String op() { return "cmp"; }
-
-
-    @Override public RegMask regmap(int i) { assert i==1 || i==2; return arm.RMASK; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
     @Override public RegMask outregmap() { return arm.FLAGS_MASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
+    // SUBS (shifted register)
+    @Override public void encoding( Encoding enc ) { arm.r_reg_subs(enc,this,arm.OP_CMP); }
 
     // General form: "cmp  rs1, rs2"
     @Override public void asm(CodeGen code, SB sb) {
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpFARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpFARM.java
index 9c287fcb..e82a2ee3 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpFARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpFARM.java
@@ -1,31 +1,22 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeFunPtr;
-import java.io.ByteArrayOutputStream;
 
 // compare instruction on float regs input(D-registers)
 public class CmpFARM extends MachConcreteNode implements MachNode{
     CmpFARM(Node cmp) {super(cmp);}
+    @Override public String op() { return "cmpf"; }
+    @Override public RegMask regmap(int i) { return arm.DMASK; }
+    @Override public RegMask outregmap() { return arm.FLAGS_MASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
+    // FCMP
+    @Override public void encoding( Encoding enc ) { arm.f_cmp(enc,this); }
     // General form: "cmp  d0, d1"
     @Override public void asm(CodeGen code, SB sb) {
         String dst = code.reg(this);
         if( dst!="flags" )  sb.p(dst).p(" = ");
         sb.p(code.reg(in(1))).p(", ").p(code.reg(in(2)));
     }
-
-    @Override public RegMask regmap(int i) { assert i==1 || i==2; return arm.DMASK; }
-    @Override public RegMask outregmap() { return arm.FLAGS_MASK; }
-
-    @Override public String op() { return "cmpf"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpIARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpIARM.java
index a0b10ba4..8a4f242a 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpIARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpIARM.java
@@ -1,46 +1,34 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 // Compare with immediate.
-// Conditional compare (immediate)? e.g CCMP(immediate)
+// CMP (immediate) - SUBS
 public class CmpIARM extends MachConcreteNode implements MachNode {
     final int _imm;
     final String _bop;
-    CmpIARM(BoolNode bool, TypeInteger ti) {
+    CmpIARM(BoolNode bool, int imm) {
         super(bool);
         _inputs.pop();
         _bop = bool.op();
-        _imm = (int)ti.value();
-        assert _imm == ti.value();
+        _imm = imm;
     }
-    // Copy constructor does not set reverse edges in, because the basic block
-    // is changing from the original node - and it must be properly placed in a
-    // new block.
     CmpIARM( CmpIARM cmp ) {
-        super(cmp);
+        super((Node)null);
+        addDef(null);
+        addDef(cmp.in(1));
         _bop = cmp._bop;
         _imm = cmp._imm;
-        // While in(0) will be handled by the caller, all other edges must be
-        // handled in the constructor.
-        cmp.in(1)._outputs.push(this);
     }
-
-    @Override public RegMask regmap(int i) { assert i==1; return arm.RMASK; }
+    @Override public String op() { return _imm==0 ? "test" : "cmp"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
     @Override public RegMask outregmap() { return arm.FLAGS_MASK; }
     @Override public boolean isClone() { return true; }
     @Override public Node copy() { return new CmpIARM(this); }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
+    @Override public void encoding( Encoding enc ) { arm.imm_inst_subs(enc,in(1),in(1), arm.OPI_CMP,_imm); }
 
     // General form: "cmp  rs1, 1"
     @Override public void asm(CodeGen code, SB sb) {
@@ -49,6 +37,4 @@ public class CmpIARM extends MachConcreteNode implements MachNode {
         sb.p(code.reg(in(1)));
         if( _imm != 0 ) sb.p(", #").p(_imm);
     }
-    @Override public String op() { return _imm==0 ? "test" : "cmp"; }
-
  }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpMemARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpMemARM.java
deleted file mode 100644
index 47f68ccc..00000000
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/CmpMemARM.java
+++ /dev/null
@@ -1,4 +0,0 @@
-package com.seaofnodes.simple.node.cpus.arm;
-
-public class CmpMemARM {
-}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/DivARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/DivARM.java
index 7c67e2dd..40bd8387 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/DivARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/DivARM.java
@@ -1,33 +1,19 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class DivARM extends MachConcreteNode implements MachNode {
     DivARM( Node div ) { super(div); }
-
-    // Register mask allowed on input i.
-    @Override public RegMask regmap(int i) {
-        assert i==1 || i==2;
-        return arm.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
+    @Override public String op() { return "div"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
+    // SDIV
+    @Override public void encoding( Encoding enc ) { arm.madd(enc,this,arm.OP_DIV,3); }
     // General form: "div  dst /= src"
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" / ").p(code.reg(in(2)));
     }
 
-    @Override public String op() { return "div"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/DivFARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/DivFARM.java
index 2137c01c..72b76444 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/DivFARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/DivFARM.java
@@ -1,30 +1,19 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class DivFARM extends MachConcreteNode implements MachNode {
     DivFARM( Node divf) { super(divf); }
-
-    // Register mask allowed on input i.
-    @Override public RegMask regmap(int i) { assert i==1 || i==2; return arm.DMASK; }
-    // Register mask allowed as a result.  0 for no register.
+    @Override public String op() { return "divf"; }
+    @Override public RegMask regmap(int i) { return arm.DMASK; }
     @Override public RegMask outregmap() {  return arm.DMASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-
+    // FDIV (scalar)
+    @Override public void encoding( Encoding enc ) { arm.f_scalar(enc,this,arm.OPF_DIV); }
     // General form: "VDIF =  dst /= src"
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" / ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "divf"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/FloatARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/FloatARM.java
index 7fafc31c..6de65b03 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/FloatARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/FloatARM.java
@@ -2,28 +2,36 @@ package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.ConstantNode;
 import com.seaofnodes.simple.node.MachNode;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.type.TypeFloat;
 
 //FMOV (scalar, immediate)
 //Floating-point move immediate.
-public class FloatARM extends ConstantNode implements MachNode {
+public class FloatARM extends ConstantNode implements MachNode, RIPRelSize {
     FloatARM(ConstantNode con) { super(con); }
-    @Override public String op() { return "fld"; }
-    // Register mask allowed on input i.  0 for no register.
+    @Override public String op() { return "ld8"; }
     @Override public RegMask regmap(int i) { return null; }
-    // General int registers
     @Override public RegMask outregmap() { return arm.DMASK; }
-
     @Override public boolean isClone() { return true; }
     @Override public FloatARM copy() { return new FloatARM(this); }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        enc.largeConstant(this,_con,0,-1/*TODO: ARM-style ELF patching*/);
+        short dst = (short)(enc.reg(this) - arm.D_OFFSET);
+        double d = ((TypeFloat)_con).value();
+        long x = Double.doubleToRawLongBits(d);
+        enc.add4(arm.load_pc(arm.OPF_ARM, 0, dst));
+    }
+
+    // Delta is from opcode start.
+    @Override public byte encSize(int delta) { return 4;  }
+
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        short dst = (short)(enc.reg(this) - arm.D_OFFSET);
+        enc.patch4(opStart, arm.load_pc(arm.OPF_ARM, delta, dst));
     }
 
     // Human-readable form appended to the SB.  Things like the encoding,
@@ -31,6 +39,7 @@ public class FloatARM extends ConstantNode implements MachNode {
     // Just something like "ld4\tR17=[R18+12] // Load array base".
     // General form: "op\tdst=src+src"
     @Override public void asm(CodeGen code, SB sb) {
-        _con.print(sb.p(code.reg(this)).p(" #"));
+        _con.print(sb.p(code.reg(this)).p(" = #"));
     }
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/FunARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/FunARM.java
index 0134911f..32777f03 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/FunARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/FunARM.java
@@ -1,21 +1,22 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.FunNode;
 import com.seaofnodes.simple.node.MachNode;
-import java.io.ByteArrayOutputStream;
 
-public class FunARM  extends FunNode implements MachNode{
-    FunARM(FunNode fun) {super(fun);}
-    // Register mask allowed on input i.  0 for no register.
-    @Override public RegMask regmap(int i) { return null; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return null; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+public class FunARM  extends FunNode implements MachNode {
+    FunARM(FunNode fun) { super(fun); }
+    @Override public void computeFrameAdjust(CodeGen code, int maxReg) {
+        super.computeFrameAdjust(code,maxReg);
+        if( _hasCalls )         // If non-leaf, pad to 16b
+            _frameAdjust = ((_frameAdjust+8) & -16);
+    }
+    @Override public void encoding( Encoding enc ) {
+        int sz = _frameAdjust;
+        if( sz == 0 ) return;   // Skip if no frame adjust
+        if( sz >= 1L<<12 ) throw Utils.TODO();
+        enc.add4(arm.imm_inst(arm.OPI_ADD, -sz&0xFFF, arm.RSP, arm.RSP));
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/I2F8ARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/I2F8ARM.java
index b106ab8a..5ecc98b6 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/I2F8ARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/I2F8ARM.java
@@ -1,29 +1,25 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
-// VCVT (between floating-point and integer)
 public class I2F8ARM extends MachConcreteNode implements MachNode {
-    I2F8ARM(Node i2f8) {super(i2f8);}
-    @Override public String op() { return "i2f8"; }
-
-    // Register mask allowed on input i.
-    @Override public RegMask regmap(int i) { assert i==1; return arm.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
+    I2F8ARM(Node i2f8) { super(i2f8); }
+    @Override public String op() { return "cvt"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
     @Override public RegMask outregmap() { return arm.DMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        // SCVTF
+        short self = (short)(enc.reg(this )-arm.D_OFFSET);
+        short reg1 = enc.reg(in(1));
+        int body = arm.float_cast(arm.OP_FLOAT_C, 1, reg1, self);
+        enc.add4(body);
     }
 
     // General form: "i2f8 (flt)int_value"
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p("(flt)").p(code.reg(in(1)));
     }
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/IntARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/IntARM.java
index 1f81300e..0a07b07a 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/IntARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/IntARM.java
@@ -1,30 +1,59 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.ConstantNode;
 import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 // Integer constants
 public class IntARM extends ConstantNode implements MachNode {
     IntARM( ConstantNode con ) { super(con); }
-    @Override public String op() { return "ldi"; }
 
-    // Register mask allowed on input i.  0 for no register.
+    @Override public String op() { return "ldi"; }
     @Override public RegMask regmap(int i) { return null; }
-    // General int registers
     @Override public RegMask outregmap() { return arm.WMASK; }
 
     @Override public boolean isClone() { return true; }
     @Override public IntARM copy() { return new IntARM(this); }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        short self = enc.reg(this);
+        long x = _con==Type.NIL ? 0 : ((TypeInteger)_con).value();
+        int nb0 = 0;
+        int nb1 = 0;
+        // Count number of 0000 and FFFF blocks
+        for (int i=0; i<64; i+=16) {
+            int block = (int)(x >> i) & 0xFFFF;
+            if (block == 0) nb0++;
+            if (block == 0xFFFF) nb1++;
+        }
+        int pattern;
+        int op;
+        if(nb0 >= nb1) {
+            // More 0 blocks then F blocks, use movz
+            pattern = 0;
+            op = arm.OP_MOVZ;
+        } else {
+            // More F blocks then 0 blocks, use movn
+            pattern = 0xFFFF;
+            op = arm.OP_MOVN;
+        }
+        int invert = pattern;
+        for (int i=0; i<4; i++) {
+            int block = (int)x & 0xFFFF;
+            x >>= 16;
+            if (block != pattern) {
+                enc.add4(arm.mov(op, i, block ^ invert, self));
+                op = arm.OP_MOVK;
+                invert = 0;
+            }
+        }
+        if (op != arm.OP_MOVK) {
+            // All blocks are the same, special case
+            enc.add4(arm.mov(op, 0, 0, self));
+        }
     }
 
     // Human-readable form appended to the SB.  Things like the encoding,
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/LoadARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/LoadARM.java
index 0d59cc47..44c13321 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/LoadARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/LoadARM.java
@@ -1,12 +1,10 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.LoadNode;
 import com.seaofnodes.simple.node.Node;
-
+import com.seaofnodes.simple.type.TypeFloat;
 
 // Load memory addressing on ARM
 // Support imm, reg(direct), or reg+off(indirect) addressing
@@ -14,24 +12,28 @@ import com.seaofnodes.simple.node.Node;
 // idx  = null
 // off  = off - offset added to base
 
-public class LoadARM extends MemOpARM{
-    LoadARM(LoadNode ld,Node base, Node idx, int off) {
+public class LoadARM extends MemOpARM {
+    LoadARM(LoadNode ld, Node base, Node idx, int off) {
         super(ld, base, idx, off, 0);
     }
-
-    @Override public RegMask regmap(int i) {
-        return arm.RMASK;
-    }
-
-    // Wide mask loads both ints and floats; encoding varies.
+    @Override public String op() { return "ld"+_sz; }
     @Override public RegMask outregmap() { return arm.MEM_MASK; }
 
+    private static final int[] OP_LOADS  = new int[]{ arm.OP_LOAD_IMM_8,  arm.OP_LOAD_IMM_16,  arm.OP_LOAD_IMM_32,  arm.OP_LOAD_IMM_64, };
+    private int imm_op() {
+        return _declaredType == TypeFloat.F32 ? arm.OPF_LOAD_IMM_32
+            :  _declaredType == TypeFloat.F64 ? arm.OPF_LOAD_IMM_64
+            :  OP_LOADS[_declaredType.log_size()];
+    }
 
-    @Override public String op() { return "ld"+_sz; }
+    private static final int[] OP_LOAD_RS  = new int[]{ arm.OP_LOAD_R_8 , arm.OP_LOAD_R_16 , arm.OP_LOAD_R_32 , arm.OP_LOAD_R_64,  };
 
+    // ldr(immediate - unsigned offset) | ldr(register)
+    @Override public void encoding( Encoding enc ) {
+        ldst_encode(enc, imm_op(), OP_LOAD_RS[_declaredType.log_size()], this, size());
+    }
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(",");
         asm_address(code,sb);
     }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/LslARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/LslARM.java
index 6108c889..055d6dcc 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/LslARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/LslARM.java
@@ -1,41 +1,19 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
-import java.lang.StringBuilder;
-
 
 // Logical Shift Left (register)
 public class LslARM extends MachConcreteNode implements MachNode {
     LslARM(Node asr) {super(asr);}
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        // assert i==1;
-        return arm.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
+    @Override public String op() { return "shr"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form: "lsl rd, rs1, rs2"
+    @Override public void encoding( Encoding enc ) { arm.shift_reg(enc,this,arm.OP_LSL); }
     @Override public void asm(CodeGen code, SB sb) {
-
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" << ").p(code.reg(in(2)));
     }
 
-    @Override public String op() { return "lsl"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/LslIARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/LslIARM.java
index 7a7014f4..94d3e25b 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/LslIARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/LslIARM.java
@@ -1,42 +1,33 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-
-import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
-import java.lang.StringBuilder;
-
+import com.seaofnodes.simple.node.MachConcreteNode;
+import com.seaofnodes.simple.node.MachNode;
+import com.seaofnodes.simple.node.Node;
 
-// Logical Shift Left (immediate)
 public class LslIARM extends MachConcreteNode implements MachNode {
-    final TypeInteger _ti;
-    LslIARM(Node lsli, TypeInteger ti) {super(lsli); _inputs.pop();  _ti = ti;}
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        // assert i==1;
-        return arm.RMASK; }
-
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    final int _imm;
+    LslIARM(Node lsl, int imm) {
+        super(lsl);
+        _inputs.pop();
+        _imm = imm;
     }
-
-    // General form
-    // General form: "lsli rd, rs1, imm"
+    @Override public String op() { return "lsli"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
+    @Override public void encoding( Encoding enc ) {
+        short rd = enc.reg(this);
+        short rn = enc.reg(in(1));
+        assert _imm > 0;
+        // UBFM <Xd>, <Xn>, #(-<shift> MOD 64), #(63-<shift>)
+        // immr must be (-<shift> MOD 64) = 64 - shift
+        enc.add4(arm.imm_shift(arm.OPI_LSL, 64 - _imm, (64 - _imm) - 1, rn, rd));
+    }
+    // General form: "lsli  rd = rs1 << imm"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" << #");
-        _ti.print(sb);
+        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" << #").p(_imm);
     }
-
-    @Override public String op() { return "lsli"; }
-}
+}
\ No newline at end of file
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/LsrARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/LsrARM.java
index e6168dee..a691e0fe 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/LsrARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/LsrARM.java
@@ -1,40 +1,19 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
-import java.lang.StringBuilder;
 
 // Logical Shift Right (register)
 public class LsrARM extends MachConcreteNode implements MachNode {
     LsrARM(Node asr) {super(asr);}
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        // assert i==1;
-        return arm.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
+    @Override public String op() { return "shr"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
 
-    // General form
-    // General form: "lsr rd, rs1, rs2"
+    @Override public void encoding( Encoding enc ) { arm.shift_reg(enc,this,arm.OP_LSR); }
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" >>> ").p(code.reg(in(2)));
     }
 
-    @Override public String op() { return "lsr"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/LsrIARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/LsrIARM.java
index 8fb20cb2..094cd30f 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/LsrIARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/LsrIARM.java
@@ -2,40 +2,28 @@ package com.seaofnodes.simple.node.cpus.arm;
 
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
-import java.lang.StringBuilder;
 
-// Logical Shift Right (immediate)
-public class LsrIARM extends MachConcreteNode implements MachNode{
-    final TypeInteger _ti;
-    LsrIARM(Node lsri, TypeInteger ti) {super(lsri); _inputs.pop();  _ti = ti;}
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        // assert i==1;
-        return arm.RMASK; }
-
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+// logical right shift immediate
+public class LsrIARM extends MachConcreteNode implements MachNode {
+    final int _imm;
+    LsrIARM(Node lsr, int imm) {
+        super(lsr);
+        _inputs.pop();
+        _imm = imm;
     }
-
-    // General form
-    // General form: "lsrl rd, rs1, imm"
+    @Override public String op() { return "lsri"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
+    @Override public void encoding( Encoding enc ) {
+        short rd = enc.reg(this);
+        short rn = enc.reg(in(1));
+        assert _imm > 0;
+        enc.add4(arm.imm_shift(arm.OPI_LSR,_imm, 0b111111, rn,rd));
+    }
+    // General form: "lsri  rd = rs1 >>> imm"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" >>> #");
-        _ti.print(sb);
+        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" >>> #").p(_imm);
     }
-
-    @Override public String op() { return "lsrl"; }
-}
+}
\ No newline at end of file
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/MemOpARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/MemOpARM.java
index adffa501..6d8344a2 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/MemOpARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/MemOpARM.java
@@ -1,57 +1,68 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.*;
-import java.io.ByteArrayOutputStream;
+
 import java.lang.StringBuilder;
 import java.util.BitSet;
 
 
-public class MemOpARM extends MemOpNode implements MachNode {
-    final int _off;             // Limit 32 bits
-    final int _imm;             // Limit 32 bits
+public abstract class MemOpARM extends MemOpNode implements MachNode {
+    final int _off;             // Limit 9 bits sized, or (13 bits<<logsize) unsigned
+    final int _imm;             // Limit ? bits
     final char _sz = (char)('0'+(1<<_declaredType.log_size()));
-    MemOpARM(MemOpNode mop, Node base, Node idx, int off, int imm) {
+    MemOpARM(MemOpNode mop, Node ptr, Node idx, int off, int imm) {
         super(mop,mop);
-        assert base._type instanceof TypeMemPtr && !(base instanceof AddNode);
-        assert ptr() == base;
-        _inputs.setX(3,idx);
+        assert ptr._type instanceof TypeMemPtr && !(ptr instanceof AddNode);
+        assert ptr() == ptr;
+        _inputs.setX(2, ptr);
+        _inputs.setX(3, idx);
         _off = off;
         _imm = imm;
     }
 
     // Store-based flavors have a value edge
-    MemOpARM( MemOpNode mop, Node base, Node idx, int off, int imm, Node val ) {
-        this(mop,base,idx,off,imm);
+    MemOpARM( MemOpNode mop, Node ptr, Node idx, int off, int imm, Node val ) {
+        this(mop,ptr,idx,off,imm);
         _inputs.setX(4,val);
     }
 
-    Node idx() { return in(3); }
-    Node val() { return in(4); } // Only for stores, includin
+    @Override public String label() { return op();}
+    Node val() { return in(4); } // Only for stores
 
     @Override public  StringBuilder _printMach(StringBuilder sb, BitSet visited) { return sb.append(".").append(_name); }
 
-    @Override public String label() { return op(); }
     @Override public Type compute() { throw Utils.TODO(); }
     @Override public Node idealize() { throw Utils.TODO(); }
 
+    int size() { return 1<<_declaredType.log_size(); }
 
-
-    // Register mask allowed on input i.
+    // Wider mask to store both GPRs and FPRs
     @Override public RegMask regmap(int i) {
-        throw Utils.TODO();
+        // 0 - ctrl
+        if( i==1 ) return null; // memory
+        if( i==2 ) return arm.RMASK; // ptr/base
+        if( i==3 ) return arm.RMASK; // off/index
+        if( i==4 ) return arm.RMASK; // value
+        return null; // Anti-dependence
     }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { throw Utils.TODO(); }
 
-    @Override public int encoding(ByteArrayOutputStream bytes) { throw Utils.TODO(); }
+    // Shared encoding for loads and stores(int and float)
+    public void ldst_encode( Encoding enc, int opcode_imm, int opcode_reg, Node xval, int size) {
+        short ptr = enc.reg(ptr());
+        short off = enc.reg(off());
+        short val = enc.reg(xval);
+        int body = off() == null
+            ? arm.load_str_imm(opcode_imm, _off, ptr, val, size)
+            : arm.indr_adr(opcode_reg, off, arm.STORE_LOAD_OPTION.SXTX, 0, ptr, val);
+        enc.add4(body);
+    }
 
     SB asm_address(CodeGen code, SB sb) {
         sb.p("[").p(code.reg(ptr())).p("+");
-        if( idx() != null ) sb.p(code.reg(idx()));
+        if( off() != null ) sb.p(code.reg(off()));
         else sb.p(_off);
         return sb.p("]");
     }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/MulARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/MulARM.java
index 582b97d4..3514db9b 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/MulARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/MulARM.java
@@ -1,34 +1,19 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-
 
 // mulh signed multiply instruction(no-imm form)
-public class MulARM extends MachConcreteNode implements MachNode{
+public class MulARM extends MachConcreteNode implements MachNode {
     MulARM(Node mul) {super(mul);}
+    @Override public String op() { return "mul"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
 
-    // Register mask allowed on input i.
-    @Override public RegMask regmap(int i) { assert i==1 || i==2; return arm.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
+    @Override public void encoding( Encoding enc ) { arm.madd(enc,this,arm.OP_MUL,31); }
     // General form: "rd = rs1 * rs2"
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" * ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "mul"; }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/MulFARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/MulFARM.java
index b71b412d..89dba172 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/MulFARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/MulFARM.java
@@ -1,30 +1,18 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import java.io.ByteArrayOutputStream;
 
 public class MulFARM extends MachConcreteNode implements MachNode{
     MulFARM(Node mulf) {super(mulf);}
-
-    // Register mask allowed on input i.
-    @Override public RegMask regmap(int i) { assert i==1 || i==2; return arm.DMASK; }
-    // Register mask allowed as a result.  0 for no register.
+    @Override public String op() { return "mulf"; }
+    @Override public RegMask regmap(int i) { return arm.DMASK; }
     @Override public RegMask outregmap() { return arm.DMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
+    @Override public void encoding( Encoding enc ) { arm.f_scalar(enc,this,arm.OPF_MUL); }
     // Default on double precision for now(64 bits)
     // General form: "VMUL.f32  rd = src1 * src2
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" * ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "mulf"; }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/MulIARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/MulIARM.java
deleted file mode 100644
index c118b00a..00000000
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/MulIARM.java
+++ /dev/null
@@ -1,43 +0,0 @@
-package com.seaofnodes.simple.node.cpus.arm;
-
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-
-public class MulIARM  extends MachConcreteNode implements MachNode{
-    final TypeInteger _ti;
-    MulIARM(Node mul, TypeInteger ti) {
-        super(mul);
-        _inputs.pop();
-        _ti = ti;
-    }
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        // assert i==1;
-        return arm.RMASK; }
-
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form: "muli  dst * #imm"
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" * #");
-        _ti.print(sb);
-    }
-
-    @Override public String op() { return "muli"; }
-}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/NegARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/NegARM.java
new file mode 100644
index 00000000..b7c3c803
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/NegARM.java
@@ -0,0 +1,25 @@
+package com.seaofnodes.simple.node.cpus.arm;
+
+import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.node.MachConcreteNode;
+import com.seaofnodes.simple.type.TypeInteger;
+
+public class NegARM extends MachConcreteNode implements MachNode {
+    NegARM(Node sub) {
+        super(sub);
+        //_inputs.pop();
+    }
+    @Override public String op() { return "neg"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap()   { return arm.WMASK; }
+    @Override public void encoding( Encoding enc ) {
+        // reverse subtract with immediate 0
+        arm.imm_inst(enc,this, in(1), 0b00100110, 0);
+    }
+    // General form: "subi  rd = rs1 - imm"
+    @Override public void asm(CodeGen code, SB sb) {
+        sb.p(code.reg(this)).p(" = -").p(code.reg(in(1)));
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/NewARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/NewARM.java
index bd88fa83..cb51eea2 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/NewARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/NewARM.java
@@ -1,31 +1,36 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 
-import java.io.ByteArrayOutputStream;
-
-public class NewARM extends NewNode implements MachNode {
+public class NewARM extends NewNode implements MachNode, RIPRelSize {
     // A pre-zeroed chunk of memory.
     NewARM(NewNode nnn) { super(nnn); }
-    // Size and pointer result in standard calling convention; null for all the
-    // memory aliases edges
-    @Override public RegMask    regmap(int i) { return i == 1 ? arm. X0_MASK : null; }
-    @Override public RegMask outregmap(int i) { return i == 1 ? arm. X0_MASK : null; }
-    @Override public RegMask outregmap() { return null; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        // BL(branch with link)
+        enc.external(this,"calloc").
+            add4(arm.mov(arm.OP_MOVZ, 0, 1, 0)).   // movz x0,#1
+            add4(arm.b(arm.OP_CALL, 0));
     }
 
-    // General form: "alloc #bytes"
+    // Patch is for running "new" in a JIT.
+    // Delta is from opcode start
+    @Override public byte encSize(int delta) { return 4*2; }
+
+    // Patch is for running "new" in a JIT.
+    // Delta is from opcode start
+    @Override public void patch(Encoding enc, int opStart, int opLen, int delta ) {
+        // Negative patches are JIT emulator targets.
+        if( opStart+delta < 0 ) {
+            enc.patch4(opStart+4, arm.b_calloc(arm.OP_CALL, delta-4));
+        } else {
+            throw Utils.TODO();
+        }
+    }
+    // General form: "alloc #bytes  PC"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(size()));
+        sb.p("ldi   x0=#1\n");
+        sb.p("call  #calloc");
     }
-
-    @Override public String op() { return "alloc"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/NotARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/NotARM.java
index 28ebd60d..5a8d882d 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/NotARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/NotARM.java
@@ -1,26 +1,28 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.LRG;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 import com.seaofnodes.simple.node.MachConcreteNode;
 
 public class NotARM extends MachConcreteNode implements MachNode{
     NotARM(NotNode not) {super(not);}
+    @Override public String op() { return "not"; }
     @Override public RegMask regmap(int i) { return arm.RMASK; }
-    @Override public RegMask outregmap() { return arm.RMASK;  }
-
-    @Override public int twoAddress( ) { return 0; }
-
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public RegMask outregmap() { return arm.WMASK;  }
+    @Override public RegMask killmap() { return arm.FLAGS_MASK; }
+    @Override public void encoding( Encoding enc ) {
+        // subs xzr, rs, #0
+        // cset    rd, eq        // Set rd to 1 if rs == 0 (equal), else 0
+        // subtracting zero from rs will just yield rs, it sets the zero flag and then it's used in cset
+        short self = enc.reg(this );
+        short reg1 = enc.reg(in(1));
+        int subs = arm.imm_inst(arm.OP_SUBS, 0, reg1, self);
+        enc.add4(subs);
+        int cset = arm.cond_set(arm.OP_CSET, 31, arm.COND.EQ, 63, reg1);
+        enc.add4(cset);
     }
 
     @Override public void asm(CodeGen code, SB sb) { sb.p(code.reg(this)); }
-    @Override public String op() { return "not"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/OrARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/OrARM.java
index 12ea8265..b5cfa8cf 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/OrARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/OrARM.java
@@ -1,42 +1,20 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.MachConcreteNode;
-import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.node.Node;
-
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
 
 // Not using the ORRS variant.
 public class OrARM extends MachConcreteNode implements MachNode {
-    OrARM(Node and) {
-        super(and);
-    }
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        assert i==1 || i==2;
-        return arm.RMASK;
-    }
-
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
+    OrARM(Node and) { super(and); }
+    @Override public String op() { return "or"; }
+    @Override public String glabel() { return "|"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
+    @Override public void encoding( Encoding enc ) { arm.r_reg(enc,this,arm.OP_OR); }
     // General form:  #rd = rs1 & rs2
     @Override public void asm(CodeGen code, SB sb) {
-
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" | ").p(code.reg(in(2)));
     }
 
-    @Override public String op() { return "orr"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/OrIARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/OrIARM.java
index f257a867..2a2d199a 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/OrIARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/OrIARM.java
@@ -1,40 +1,24 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.MachConcreteNode;
-import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.node.Node;
+import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
 
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-
-public class OrIARM extends MachConcreteNode implements MachNode{
-    final TypeInteger _ti;
-    OrIARM(Node or, TypeInteger ti) {super(or);  _inputs.pop(); _ti = ti;}
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        assert i==1 || i==2;
-        return arm.RMASK;
+public class OrIARM extends MachConcreteNode implements MachNode {
+    final int _imm;
+    OrIARM(Node or, int imm) {
+        super(or);
+        _inputs.pop();
+        _imm = imm;
     }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public String op() { return "ori"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
+    @Override public void encoding( Encoding enc ) {
+        arm.imm_inst_n(enc, this, in(1), arm.OPI_OR, _imm);
     }
-
-    // General form
-    // General form: "rd = rs1 | imm"
+    // General form: "ori  rd = rs1 | imm"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" | #");
-        _ti.print(sb);
+        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" | #").p(_imm);
     }
-
-    @Override public String op() { return "ori"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/ParmARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/ParmARM.java
index c3fa132c..b419fe0a 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/ParmARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/ParmARM.java
@@ -1,25 +1,17 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.node.ParmNode;
-import java.io.ByteArrayOutputStream;
 
 public class ParmARM extends ParmNode implements MachNode {
     final RegMask _rmask;
     ParmARM(ParmNode parm) {
         super(parm);
-        // Assume int
-        _rmask = arm.callInMask(fun().sig(),_idx);
+        _rmask = arm.callInMask(fun().sig(),_idx,0);
     }
-    // Register mask allowed on input i.  0 for no register.
     @Override public RegMask regmap(int i) { return null; }
-    // Register mask allowed as a result.  Calling convention register
     @Override public RegMask outregmap() { return _rmask; }
-
-    // Encoding is appended into the byte array.  Returns size
-    @Override public int encoding(ByteArrayOutputStream bytes) { return 0; }
+    @Override public void encoding( Encoding enc ) { }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/ProjARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/ProjARM.java
index b2add015..4b7d6f13 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/ProjARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/ProjARM.java
@@ -1,23 +1,15 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.node.ProjNode;
-import java.io.ByteArrayOutputStream;
 
 public class ProjARM extends ProjNode implements MachNode {
     ProjARM( ProjNode p ) { super(p); }
-
-    // Register mask allowed on input i.  0 for no register.
     @Override public RegMask regmap(int i) { return null; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() {
         return ((MachNode)in(0)).outregmap(_idx);
     }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
+    @Override public void encoding( Encoding enc ) { }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/RetARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/RetARM.java
index c7d0dd4c..2136ebf5 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/RetARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/RetARM.java
@@ -1,49 +1,15 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.FunNode;
-import com.seaofnodes.simple.node.ReturnNode;
-import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.type.TypeFloat;
-
-import java.io.ByteArrayOutputStream;
-
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
 
 public class RetARM extends ReturnNode implements MachNode {
     RetARM(ReturnNode ret, FunNode fun) { super(ret, fun); fun.setRet(this); }
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) { return arm.retMask(_fun.sig(),i); }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return null; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    @Override public void asm(CodeGen code, SB sb) {
-        // Post code-gen, just print the "ret"
-        if( code._phase.ordinal() <= CodeGen.Phase.RegAlloc.ordinal() )
-            // Prints return reg (either X0 or D0), RPC (always R30) and
-            // then the callee-save registers.
-            for( int i=2; i<nIns(); i++ )
-                sb.p(code.reg(in(i))).p("  ");
-
-        // Post-allocation, if we did not get the expected return register, print what we got
-        else if( code._regAlloc.regnum(in(3)) != arm.X30 )
-            sb.p("[").p(code.reg(in(3))).p("]");
+    @Override public void encoding( Encoding enc ) {
+        int frameAdjust = ((FunARM)fun())._frameAdjust;
+        if( frameAdjust > 0 )
+            enc.add4(arm.imm_inst(arm.OPI_ADD, (frameAdjust*-8)&0xFFF, arm.RSP, arm.RSP));
+        enc.add4(arm.ret(arm.OP_RET));
     }
-
-    // Correct Nodes outside the normal edges
-    @Override public void postSelect() {
-        FunNode fun = (FunNode)rpc().in(0);
-        _fun = fun;
-        fun.setRet(this);
-    }
-
-    @Override public String op() { return "ret"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/SetARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/SetARM.java
index c3945d1a..246e482a 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/SetARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/SetARM.java
@@ -1,20 +1,13 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-
 
 // conditional set?
 // e.g CSET, stores flag info into GPRS after compare
-
 public class SetARM extends MachConcreteNode implements MachNode {
     final String _bop;          // One of <,<=,==
-
     SetARM(Node cmp, String bop) {
         super(cmp);
         _inputs.setLen(1);   // Pop the cmp inputs
@@ -22,13 +15,13 @@ public class SetARM extends MachConcreteNode implements MachNode {
         _inputs.push(cmp);
         _bop = bop;
     }
-
+    @Override public String op() { return "set"+_bop; }
     @Override public RegMask regmap(int i) { assert i==1; return arm.FLAGS_MASK; }
-    @Override public RegMask outregmap() { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        int body = arm.cset(arm.OP_CSET,0b11111, arm.make_condition(_bop), 0b011111, enc.reg(this));
+        enc.add4(body);
     }
 
     @Override public void asm(CodeGen code, SB sb) {
@@ -36,6 +29,4 @@ public class SetARM extends MachConcreteNode implements MachNode {
         String src = code.reg(in(1));
         if( src!="flags" )  sb.p(" = ").p(src);
     }
-
-    @Override public String op() { return "set"+_bop; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/SplitARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/SplitARM.java
index 85771842..62bb75aa 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/SplitARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/SplitARM.java
@@ -1,22 +1,66 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
+import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.FunNode;
 import com.seaofnodes.simple.node.Node;
 import com.seaofnodes.simple.node.SplitNode;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.node.cpus.riscv.riscv;
 
 public class SplitARM extends SplitNode {
     SplitARM(String kind, byte round) { super(kind,round,new Node[2]);}
-
-    // Register mask allowed on input i.
     @Override public RegMask regmap(int i) { return arm.SPLIT_MASK; }
-
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return arm.SPLIT_MASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        short dst = enc.reg(this );
+        short src = enc.reg(in(1));
+
+        boolean dstX = dst >= arm.D_OFFSET;
+        boolean srcX = src >= arm.D_OFFSET;
+
+        if (dst >= arm.MAX_REG) {
+            // store to sp
+            if(src >= arm.MAX_REG) {
+                throw Utils.TODO();
+            }
+            int off = enc._fun.computeStackOffset(enc._code,dst);
+            if( srcX ) src -= arm.D_OFFSET;
+            enc.add4(arm.load_str_imm(arm.OP_STORE_IMM_64, off, arm.RSP, src, 8));
+            return;
+        }
+
+        if(src >= arm.MAX_REG) {
+            // Load from SP
+            int off = enc._fun.computeStackOffset(enc._code,src);
+            if( dstX ) dst -= arm.D_OFFSET;
+            enc.add4(arm.load_str_imm(arm.OP_LOAD_IMM_64, off, arm.RSP, dst, 8));
+            return;
+        }
+
+        // pick opcode based on regs
+        if(!dstX && !srcX) {
+            // GPR->GPR
+            enc.add4(arm.mov_reg(arm.OP_MOV, src, dst));
+        } else if(dstX && srcX) {
+            // FPR->FPR
+            // fmov reg
+            enc.add4(arm.f_mov_reg(arm.OP_FMOV_REG, src - arm.D_OFFSET,dst - arm.D_OFFSET));
+        } else if(!srcX && dstX) {
+            // GPR->FPR
+            // FMOV(general) 64 bits to DOUBLE-PRECISION
+            enc.add4(arm.f_mov_general(arm.OP_FMOV, 0b01, 0, 0b111, src, dst - arm.D_OFFSET));
+        } else if( srcX && !dstX) {
+            //FPF->GPR
+            // FMOV(general) DOUBLE-PRECISION to 64 bits
+            enc.add4(arm.f_mov_general(arm.OP_FMOV, 0b01, 0, 0b110, src - arm.D_OFFSET, dst));
+        }
+    }
+
+    // General form: "mov  dst = src"
+    @Override public void asm(CodeGen code, SB sb) {
+        FunNode fun = code._encoding==null ? null : code._encoding._fun;
+        sb.p(code.reg(this,fun)).p(" = ").p(code.reg(in(1),fun));
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/StoreARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/StoreARM.java
index 49045b28..688d8731 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/StoreARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/StoreARM.java
@@ -1,49 +1,40 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.MachConcreteNode;
-import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.node.Node;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.StoreNode;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
+import com.seaofnodes.simple.node.Node;
+import com.seaofnodes.simple.type.TypeFloat;
 
 // Store memory addressing on ARM
 // Support imm, reg(direct), or reg+off(indirect) addressing
-// Base = base - base pointer, offset is added to base
-// idx  = null
-// off  = off - offset added to base)
-// imm  = imm - immediate value to store
-// val  = Node of immediate value to store(null if its a constant immediate)
+// base - base pointer, offset is added to base
+// null - index never allowed (no [reg+reg] mode)
+// off  - offset added to base
+// imm  - immediate value to store, only if val is null
+// val  - value to store or null
 
 //e.g s.cs[0] =  67; // C
 // base = s.cs, off = 4, imm = 67, val = null
 public class StoreARM extends MemOpARM {
-    StoreARM(StoreNode st, Node base, Node idx, int off, int imm, Node val) {
-        super(st, base, idx, off, imm, val);
+    StoreARM(StoreNode st, Node base, Node idx, int off, Node val) {
+        super(st, base, idx, off, 0, val);
     }
-
     @Override public String op() { return "st"+_sz; }
-
-    // Wider mask to store both GPRs and FPRs
-    @Override public RegMask regmap(int i) {
-        if( i==1 ) return arm.MEM_MASK;
-        if( i==2 ) return arm.RMASK;
-        if( i==3 ) return arm.RMASK;
-        if( i==4 ) return arm.RMASK;
-        throw Utils.TODO();
-    }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return null; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    private static final int[] OP_STORES = new int[]{ arm.OP_STORE_IMM_8, arm.OP_STORE_IMM_16, arm.OP_STORE_IMM_32, arm.OP_STORE_IMM_64, };
+    private int imm_op() {
+        return _declaredType == TypeFloat.F32 ? arm.OPF_STORE_IMM_32
+            :  _declaredType == TypeFloat.F64 ? arm.OPF_STORE_IMM_64
+            :  OP_STORES[_declaredType.log_size()];
     }
 
+    private static final int[] OP_STORE_RS = new int[]{ arm.OP_STORE_R_8, arm.OP_STORE_R_16, arm.OP_STORE_R_32, arm.OP_STORE_R_64, };
+
+    @Override public void encoding( Encoding enc ) {
+        ldst_encode(enc, imm_op(), OP_STORE_RS[_declaredType.log_size()], val(), size());
+    }
     @Override public void asm(CodeGen code, SB sb) {
         asm_address(code,sb).p(",");
         if( val()==null ) sb.p("#").p(_imm);
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/SubARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/SubARM.java
index 27555b53..552b46df 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/SubARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/SubARM.java
@@ -1,30 +1,19 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-
 
 public class SubARM extends MachConcreteNode implements MachNode {
-    SubARM(Node sub) {super(sub);}
-
-    // Register mask allowed on input i.
-    @Override public RegMask regmap(int i) { assert i==1 || i==2; return arm.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
+    SubARM(Node sub) { super(sub); }
+    @Override public String op() { return "sub"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
+    @Override public void encoding( Encoding enc ) { arm.r_reg(enc,this,arm.OP_SUB); }
 
     // General form: "sub  # rd = rs1 - rs2"
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" - ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "sub"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/SubFARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/SubFARM.java
index 8ae05b40..0d8d3c10 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/SubFARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/SubFARM.java
@@ -1,32 +1,18 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
-public class SubFARM extends MachConcreteNode implements MachNode{
+public class SubFARM extends MachConcreteNode implements MachNode {
     SubFARM(Node subf) {super(subf);}
-
-    // Register mask allowed on input i.
-    @Override public RegMask regmap(int i) { assert i==1 || i==2; return arm.DMASK; }
-    // Register mask allowed as a result.  0 for no register.
+    @Override public String op() { return "subf"; }
+    @Override public RegMask regmap(int i) { return arm.DMASK; }
     @Override public RegMask outregmap() { return arm.DMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
+    @Override public void encoding( Encoding enc ) { arm.f_scalar(enc,this,arm.OPF_SUB); }
     // Default on double precision for now(64 bits)
     // General form: "vsub.f32  rd = src1 + src2
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" - ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "subf"; }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/SubIARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/SubIARM.java
index d19210cb..b882c5a4 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/SubIARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/SubIARM.java
@@ -1,42 +1,29 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.MachConcreteNode;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.LRG;
-import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class SubIARM extends MachConcreteNode implements MachNode {
-    final TypeInteger _ti;
-    SubIARM(Node sub, TypeInteger ti) {
+    final int _imm;
+    SubIARM(Node sub, int imm) {
         super(sub);
         _inputs.pop();
-        _ti = ti;
+        _imm = imm;
     }
-
-    // Register mask allowed on input i.
+    @Override public String op() { return _imm == -1 ? "dec" : "subi"; }
     @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
 
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        arm.imm_inst(enc,this, in(1), arm.OPI_SUB,_imm);
     }
 
     // General form: "subi  rd = rs1 - imm"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" - #");
-        _ti.print(sb);
+        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" - #").p(_imm);
     }
-
-    @Override public String op() {
-        return (_ti.value() == -1 ? "dec" : "subi");
-    }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/TFPARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/TFPARM.java
index cdb2b6ec..16b56553 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/TFPARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/TFPARM.java
@@ -1,37 +1,53 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.ConstantNode;
 import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.node.cpus.riscv.riscv;
 import com.seaofnodes.simple.type.TypeFunPtr;
-import java.io.ByteArrayOutputStream;
 
-public class TFPARM extends ConstantNode implements MachNode {
+public class TFPARM extends ConstantNode implements MachNode, RIPRelSize {
     TFPARM( ConstantNode con ) { super(con); }
     @Override public String op() { return "ldx"; }
-    // Register mask allowed on input i.  0 for no register.
     @Override public RegMask regmap(int i) { return null; }
-    // General int registers
     @Override public RegMask outregmap() { return arm.WMASK; }
-
     @Override public boolean isClone() { return true; }
     @Override public TFPARM copy() { return new TFPARM(this); }
+    @Override public void encoding( Encoding enc ) {
+        enc.relo(this);
+        short self = enc.reg(this);
+        // adrp    x0, 0
+        int adrp = arm.adrp(1,0, arm.OP_ADRP, 0,self);
+        // add     x0, x0, 0
+        enc.add4(adrp);
+        arm.imm_inst(enc,arm.OPI_ADD,0, 0);
+    }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
+    @Override public byte encSize(int delta) {
+        if( -(1L<<12) <= delta && delta < (1L<<12) ) return 4;
         throw Utils.TODO();
     }
 
-    // Human-readable form appended to the SB.  Things like the encoding,
-    // indentation, leading address or block labels not printed here.
-    // Just something like "ld4\tR17=[R18+12] // Load array base".
-    // General form: "op\tdst=src+src"
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        short rpc = enc.reg(this);
+        if(opLen == 8 ) {
+            // opstart of add
+            int next = opStart + opLen;
+            int adrp_delta = delta >> 12;
+            // patch upper 20 bits via adrp
+            enc.patch4(opStart, arm.adrp(1, adrp_delta & 0b11, 0b10000, adrp_delta >> 2, rpc));
+            // low 12 bits via add
+            enc.patch4(next, arm.imm_inst_l(arm.OPI_ADD, delta & 0xfff, rpc));
+        } else {
+            // should not happen as one instruction is 4 byte, and TFP arm encodes 2.
+            throw Utils.TODO();
+        }
+    }
+
     @Override public void asm(CodeGen code, SB sb) {
         String reg = code.reg(this);
         _con.print(sb.p(reg).p(" #"));
     }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/UJmpARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/UJmpARM.java
new file mode 100644
index 00000000..a69c3c7c
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/UJmpARM.java
@@ -0,0 +1,48 @@
+package com.seaofnodes.simple.node.cpus.arm;
+
+import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.Type;
+import java.util.BitSet;
+
+// unconditional jump
+public class UJmpARM extends CFGNode implements MachNode, RIPRelSize {
+    UJmpARM() { }
+    @Override public String op() { return "jmp"; }
+    @Override public String label() { return op(); }
+    @Override public StringBuilder _print1( StringBuilder sb, BitSet visited ) {
+        return sb.append("jmp ");
+    }
+    @Override public RegMask regmap(int i) {return null; }
+    @Override public RegMask outregmap() { return null; }
+    @Override public Type compute() { throw Utils.TODO(); }
+    @Override public Node idealize() { throw Utils.TODO(); }
+    @Override public void encoding( Encoding enc ) {
+        enc.jump(this,uctrl());
+        int body = arm.b(arm.OP_UJMP, 0);
+        enc.add4(body);
+    }
+
+    // Delta is from opcode start
+    @Override public byte encSize(int delta) {
+        if( -(1<<26) <= delta && delta < (1<<26) ) return 4;
+        // 2 word encoding needs a tmp register, must teach RA
+        throw Utils.TODO();
+    }
+
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        if( opLen==4 ) {
+            enc.patch4(opStart,arm.b(arm.OP_UJMP, delta));
+        } else {
+            throw Utils.TODO();
+        }
+    }
+
+    @Override public void asm(CodeGen code, SB sb) {
+        CFGNode target = uctrl();
+        //assert target.nOuts() > 1; // Should optimize jmp to empty targets
+        sb.p(label(target));
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/XorARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/XorARM.java
index fd127b18..ec86cfa5 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/XorARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/XorARM.java
@@ -1,41 +1,19 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.MachConcreteNode;
-import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.node.Node;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
 
 public class XorARM extends MachConcreteNode implements MachNode{
-    XorARM(Node xor) {super(xor); _inputs.pop();}
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        assert i==1 || i==2;
-
-        return arm.RMASK; }
-
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
+    XorARM(Node xor) {super(xor);}
+    @Override public String op() { return "xor"; }
+    @Override public String glabel() { return "^"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
+    @Override public void encoding( Encoding enc ) { arm.r_reg(enc,this,arm.OP_XOR); }
     // General form: "rd = x1 ^ x2"
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" ^ ").p(code.reg(in(2)));
     }
 
-    @Override public String op() { return "eor"; }
-}
\ No newline at end of file
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/XorIARM.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/XorIARM.java
index d230ea47..e2582d22 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/XorIARM.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/XorIARM.java
@@ -1,43 +1,27 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
-import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.node.MachConcreteNode;
 import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.node.Node;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
-public class XorIARM extends MachConcreteNode implements MachNode{
-    final TypeInteger _ti;
-    XorIARM(Node xor, TypeInteger ti) {super(xor); _inputs.pop(); _ti = ti;}
+import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
 
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        assert i==1 || i==2;
-
-        return arm.RMASK; }
-
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return arm.RMASK; }
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+public class XorIARM extends MachConcreteNode implements MachNode {
+    final int _imm;
+    XorIARM(Node xor, int imm) {
+        super(xor);
+        _inputs.pop();
+        _imm = imm;
     }
 
-    // General form
-    // General form: "rd = rs1 ^ imm"
+    @Override public String op() { return "xori"; }
+    @Override public RegMask regmap(int i) { return arm.RMASK; }
+    @Override public RegMask outregmap() { return arm.WMASK; }
+
+    // General form: "xori  rd = rs1 ^ imm"
+    @Override public void encoding( Encoding enc ) { arm.imm_inst_n(enc,this, in(1), arm.OPI_XOR,_imm); }
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" ^ #");
-        _ti.print(sb);
+        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" ^ #").p(_imm);
     }
-
-    @Override public String op() { return "eor"; }
-}
\ No newline at end of file
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/arm.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/arm.java
index fd207157..3e39adc0 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/arm.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/arm/arm.java
@@ -1,30 +1,34 @@
 package com.seaofnodes.simple.node.cpus.arm;
 
 import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.LRG;
-import com.seaofnodes.simple.codegen.Machine;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.*;
 
 public class arm extends Machine {
+    public arm( CodeGen code ) {
+        if( !"SystemV".equals(code._callingConv) )
+            throw new IllegalArgumentException("Unknown calling convention "+code._callingConv);
+    }
 
-    // X86-64 V2.  Includes e.g. SSE4.2 and POPCNT.
+    // ARM64
     @Override public String name() { return "arm"; }
 
     // GPR(S)
-    static final int X0  =  0,  X1  =  1,  X2  =  2,  X3  =  3,  X4  =  4,  X5  =  5,  X6  =  6,  X7  =  7;
-    static final int X8  =  8,  X9  =  9,  X10 = 10,  X11 = 11,  X12 = 12,  X13 = 13,  X14 = 14,  X15 = 15;
-    static final int X16 = 16,  X17 = 17,  X18 = 18,  X19 = 19,  X20 = 20,  X21 = 21,  X22 = 22,  X23 = 23;
-    static final int X24 = 24,  X25 = 25,  X26 = 26,  X27 = 27,  X28 = 28,  X29 = 29,  X30 = 30,  RSP = 31;
+    public static final int X0  =  0,  X1  =  1,  X2  =  2,  X3  =  3,  X4  =  4,  X5  =  5,  X6  =  6,  X7  =  7;
+    public static final int X8  =  8,  X9  =  9,  X10 = 10,  X11 = 11,  X12 = 12,  X13 = 13,  X14 = 14,  X15 = 15;
+    public static final int X16 = 16,  X17 = 17,  X18 = 18,  X19 = 19,  X20 = 20,  X21 = 21,  X22 = 22,  X23 = 23;
+    public static final int X24 = 24,  X25 = 25,  X26 = 26,  X27 = 27,  X28 = 28,  X29 = 29,  X30 = 30,  RSP = 31;
 
     // Floating point registers
-    static final int D0  = 32,  D1  = 33,  D2  = 34,  D3  = 35,  D4  = 36,  D5  = 37,  D6  = 38,  D7  = 39;
-    static final int D8  = 40,  D9  = 41,  D10 = 42,  D11 = 43,  D12 = 44,  D13 = 45,  D14 = 46,  D15 = 47;
-    static final int D16 = 48,  D17 = 49,  D18 = 50,  D19 = 51,  D20 = 52,  D21 = 53,  D22 = 54,  D23 = 55;
-    static final int D24 = 56,  D25 = 57,  D26 = 58,  D27 = 59,  D28 = 60,  D29 = 61,  D30 = 62,  D31 = 63;
+    public static final int D0  = 32,  D1  = 33,  D2  = 34,  D3  = 35,  D4  = 36,  D5  = 37,  D6  = 38,  D7  = 39;
+    public static final int D8  = 40,  D9  = 41,  D10 = 42,  D11 = 43,  D12 = 44,  D13 = 45,  D14 = 46,  D15 = 47;
+    public static final int D16 = 48,  D17 = 49,  D18 = 50,  D19 = 51,  D20 = 52,  D21 = 53,  D22 = 54,  D23 = 55;
+    public static final int D24 = 56,  D25 = 57,  D26 = 58,  D27 = 59,  D28 = 60,  D29 = 61,  D30 = 62,  D31 = 63;
 
     static final int FLAGS = 64;
+    static final int MAX_REG = 65;
+    public static final int D_OFFSET = 32;
 
     static final String[] REGS = new String[] {
         "X0",  "X1",  "X2",  "X3",  "X4",  "X5",  "X6",  "X7",
@@ -37,9 +41,7 @@ public class arm extends Machine {
         "D24", "D25", "D26", "D27", "D28", "D29", "D30", "D31",
         "flags"
     };
-    @Override public String reg( int reg ) {
-        return reg < REGS.length ? REGS[reg] : "[rsp+"+(reg-REGS.length)*4+"]";
-    }
+    @Override public String[] regs() { return REGS; }
 
     // from (x0-x30)
     // General purpose register mask: pointers and ints, not floats
@@ -55,11 +57,9 @@ public class arm extends Machine {
     // Load/store mask; both GPR and FPR
     static final RegMask MEM_MASK = new RegMask(WR_BITS | FP_BITS);
 
-    static final RegMask SPLIT_MASK = new RegMask(WR_BITS | FP_BITS, -1L);
+    static final RegMask SPLIT_MASK = new RegMask(WR_BITS | FP_BITS, -2L/*skip flags*/);
 
     static final RegMask FLAGS_MASK = new RegMask(FLAGS);
-    //  x30 (LR): Procedure link register, used to return from subroutines.
-    static final RegMask RPC_MASK = new RegMask(1L << X30);
 
     // Arguments masks
     static final RegMask X0_MASK = new RegMask(X0);
@@ -81,6 +81,102 @@ public class arm extends Machine {
     static final RegMask D6_MASK = new RegMask(D6);
     static final RegMask D7_MASK = new RegMask(D7);
 
+    // major opcode: OP
+    public static int OP_ADD       = 0b10_001_011;
+    public static int OPF_ADD      = 0b00_011_110;
+    public static int OPF_OP_ADD   = 0b00_101_0;
+    public static int OPI_ADD      = 0b10_010_00100;
+
+    public static int OPI_SUB      = 0b11_010_00100;
+    public static int OP_UJMP      = 0b000101;
+
+    public static int OP_ADRP      = 0b10000;
+
+    public static int OP_ASR       = 0b1010;
+    public static int OPI_ASR      = 0b10_0100_1101;
+
+    public static int OP_LSL       = 0b1000;
+    public static int OPI_LSL       =0b1101001101;
+
+    public static int OP_LSR        = 0b1001;
+    public static int OPI_LSR       = 0b1101001101;
+
+    public static int OP_BRANCH    = 0b01_0101_00;
+    public static int OP_CALL      = 0b10_010_1;
+
+    public static int OP_CALLRARM  = 0b1101011000111111000000;
+
+    public static int OP_SUBS      = 0b1111000100;
+    public static int OP_CSET      = 0b10011010100;
+    public static int OP_CMP       = 0b11101011;
+    public static int OPI_CMP      = 0b1111000100;
+
+    public static int OP_DIV       = 0b10011010110;
+    public static int OPF_DIV      = 0b000110;
+
+    public static int OP_MUL       = 0b10011011000;
+    public static int OPF_MUL      =  0b10;
+
+    public static int OPF_ARM      = 0b01011100;
+
+    public static int OP_FLOAT_C   = 0b10011110;
+
+    public static int OP_XOR       = 0b11001010;
+    public static int OPI_XOR      = 0b110100100;
+
+    public static int OP_AND       = 0b10_0010_10;
+    public static int OPI_AND      = 0b10_0100_100;
+
+    public static int OP_OR        = 0b10101010;
+    public static int OPI_OR       = 0b101100100;
+
+    public static int OP_SUB       = 0b11001011;
+    public static int OPF_SUB      = 0b1110;
+
+    public static int OP_MOVK      = 0b111100101;
+    public static int OP_MOVN      = 0b100100101;
+    public static int OP_MOVZ      = 0b110100101;
+
+    public static int OP_RET       = 0b1101011001011111000000;
+    // Store/load opcodes
+    public static int OP_LOAD_R_64    = 0b11111000011;
+    public static int OP_LOAD_R_32    = 0b10111000011;
+    public static int OP_LOAD_R_16    = 0b01111000010;
+    public static int OP_LOAD_R_8     = 0b00111000011;
+
+    public static int OP_LOAD_IMM_64  = 0b1111100101;
+    public static int OP_LOAD_IMM_32  = 0b1011100101;
+    public static int OP_LOAD_IMM_16  = 0b0111100101;
+    public static int OP_LOAD_IMM_8   = 0b0011100101;
+
+    // load
+    public static int OPF_LOAD_R_64    = 0b11111100011;
+    public static int OPF_LOAD_R_32    = 0b10111100011;
+
+    public static int OPF_LOAD_IMM_64  = 0b1111110101;
+    public static int OPF_LOAD_IMM_32  = 0b1011110101;
+
+    public static int OP_STORE_R_64    = 0b11111000001;
+    public static int OP_STORE_R_32    = 0b10111000001;
+    public static int OP_STORE_R_16    = 0b01111000001;
+    public static int OP_STORE_R_8     = 0b00111000001;
+
+    public static int OP_STORE_IMM_64  = 0b1111100100;
+    public static int OP_STORE_IMM_32  = 0b1011100100;
+    public static int OP_STORE_IMM_16  = 0b0111100100;
+    public static int OP_STORE_IMM_8   = 0b0011100100;
+
+    public static int OPF_STORE_R_64    = 0b11111100001;
+    public static int OPF_STORE_R_32    = 0b10111100001;
+
+    public static int OPF_STORE_IMM_32  = 0b1111110100;
+    public static int OPF_STORE_IMM_64  = 0b1111110100;
+
+
+    public static int OP_FMOV        = 0b10011110;
+    public static int OP_FMOV_REG    = 0b00011110;
+    // https://docsmirror.github.io/A64/2023-06/mov_orr_log_shift.html
+    public static int OP_MOV         = 0b10101010000;
     // Calling convention; returns a machine-specific register
     // for incoming argument idx.
     // index 0 for control, 1 for memory, real args start at index 2
@@ -105,13 +201,376 @@ public class arm extends Machine {
         D7_MASK,
     };
 
-    static RegMask callInMask( TypeFunPtr tfp, int idx ) {
-        if( idx==0 ) return RPC_MASK;
+    // ARM ENCODING
+    public enum OPTION {
+        UXTB,
+        UXTH,
+        UXTX,
+        SXTB,
+        SXTH,
+        SXTW,
+        SXTX,
+    }
+
+    static public int cset(int opcode, int rm, COND cond, int rn, int rd) {
+        assert 0 <= rm && rm < 32;
+        assert 0 <= rn && rn < 32;
+        assert 0 <= rd && rd < 32;
+        return (opcode << 21) | (rm << 15) | (cond.ordinal() << 12) | (rn << 5) | rd;
+    }
+
+    static public int cset(int opcode, COND cond, int rn, int rd) {
+        assert 0 <= rn && rn < 32;
+        assert 0 <= rd && rd < 32;
+        return (opcode << 16) | (cond.ordinal() << 12) | (rn << 5) | rd;
+    }
+
+    public enum STORE_LOAD_OPTION {
+        UXTW,  // base+ u32 index [<< logsize]
+        UXTX,  // base+ u64 index [<< logsize]
+        SXTW,  // base+ s32 index [<< logsize]
+        SXTX,  // base+ s64 index [<< logsize]
+    }
+
+    public enum COND {
+        EQ,
+        NE,
+        CS,
+        CC,
+        MI,
+        PL,
+        VS,
+        VC,
+        HI,
+        LS,
+        GE,
+        LT,
+        GT,
+        LE,
+        AL,
+        NV
+    }
+
+    // True if signed 9-bit immediate
+    private static boolean imm9(TypeInteger ti) {
+        // 55 = 64-9
+        return ti.isConstant() && ((ti.value()<<55)>>55) == ti.value();
+    }
+    // True if signed 12-bit immediate
+    private static boolean imm12(TypeInteger ti) {
+        // 52 = 64-12
+        return ti.isConstant() && ((ti.value()<<52)>>52) == ti.value();
+    }
+
+
+    // Can we encode this in ARM's 12-bit LOGICAL immediate form?
+    // Some combination of shifted bit-masks.
+    private static int imm12Logical(TypeInteger ti) {
+        if( !ti.isConstant() ) return -1;
+        if( !ti.isConstant() ) return -1;
+        long val = ti.value();
+        if (val == 0 || val == -1) return -1; // Special cases are not allowed
+        int immr = 0;
+        // Rotate until we have 0[...]1
+
+        // Rotate until:
+        // The number is negative (MSB is 1)
+        // Or the LSB is not 1
+        while (val < 0 || (val & 1)==0) {
+            // circular rotation
+            val = (val >>> 63) | (val << 1);
+            immr++;
+        }
+        // Start by assuming that val might be made of two 32-bit chunks that repeat.
+        int size = 32;
+        long pattern = val;
+        // Is upper half of pattern the same as the lower?
+        while ((pattern & ((1L<<size)-1)) == (pattern >> size)) {
+            // Then only take one half
+            pattern >>= size;
+            size >>= 1;
+        }
+        size <<= 1;
+        int imms = Long.bitCount(pattern);
+        // Pattern should now be zeros followed by ones 0000011111
+        if (pattern != (1L<<imms)-1) return -1;
+        imms--;
+        if (size == 64) return 0x1000 | immr << 6 | imms;
+        return (32-size)<<1 | immr << 6 | imms;
+    }
+
+    // sh is encoded in opcode
+    public static int imm_inst(int opcode, int imm12, int rn, int rd) {
+        assert 0 <= rn && rn < 32;
+        assert 0 <= rd && rd < 32;
+        assert opcode >=0 && imm12 >= 0; // Caller zeros high order bits
+        return (opcode << 22) | (imm12 << 10) | (rn << 5) | rd;
+    }
+
+    public static int imm_shift(int opcode, int imm, int imms, int rn,  int rd)  {
+        assert 0 <= rn && rn < 32;
+        assert 0 <= rd && rd < 32;
+        return (opcode << 22) | (1 << 22) | (imm << 16) | (imms << 10) | (rn << 5) | rd;
+    }
+
+    public static void imm_inst(Encoding enc, Node n,Node n2,  int opcode, int imm12) {
+        short self = enc.reg(n);
+        short reg1 = enc.reg(n2);
+
+        int body = imm_inst(opcode, imm12&0xFFF, reg1, self);
+        enc.add4(body);
+    }
+
+    public static void imm_inst_subs(Encoding enc, Node n,Node n2,  int opcode, int imm12) {
+        short reg1 = enc.reg(n2);
+        // 31 = 11111
+        int body = imm_inst(opcode, imm12&0xFFF, reg1, 31);
+        enc.add4(body);
+    }
+
+    // for cases where rs1 and dst are the same, eg add x0, x0, 1
+    public static void imm_inst(Encoding enc, int opcode, int imm12, int self) {
+        int body = imm_inst(opcode, imm12&0xFFF, self, self);
+        enc.add4(body);
+    }
+
+    public static void imm_inst_n(Encoding enc, Node n, Node n2, int opcode, int imm13) {
+        short self = enc.reg(n);
+        short reg1 = enc.reg(n2);
+        int body = imm_inst_n(opcode, imm13, reg1, self);
+        enc.add4(body);
+    }
+
+    // nth bit comes from immediate and not opcode
+    public static int imm_inst_n(int opcode, int imm13, int rn, int rd) {
+        assert 0 <= rn && rn < 32;
+        assert 0 <= rd && rd < 32;
+        assert 0 <= imm13 && imm13 <= 0x1FFF;
+        return (opcode << 23) | (imm13 << 10) | (rn << 5) | rd;
+    }
+
+    public static int imm_inst_l(int opcode, int imm12, int self) {
+        int body = imm_inst(opcode, imm12&0xFFF, self, self);
+        return body;
+    }
+
+    // for cases where rs1 and dst are the same, eg add x0, x0, 1
+    public static int imm_inst_l(Encoding enc, Node n, int opcode, int imm12) {
+        short self = enc.reg(n);
+        short reg1 = enc.reg(n.in(1));
+        int body = imm_inst(opcode, imm12&0xFFF, reg1, self);
+        return body;
+    }
+
+    // for normal add, reg1, reg2 cases (reg-to-reg)
+    // using shifted-reg form
+    public static int r_reg(int opcode, int shift, int rm, int imm6, int rn, int rd) {
+        assert 0 <= rm && rm < 32;
+        assert 0 <= rn && rn < 32;
+        assert 0 <= rd && rd < 32;
+        return (opcode << 24) | (shift << 21) | (rm << 16) | (imm6 << 10) | (rn << 5) | rd;
+    }
+    public static void r_reg(Encoding enc, Node n, int opcode) {
+        short self = enc.reg(n);
+        short reg1 = enc.reg(n.in(1));
+        short reg2 = enc.reg(n.in(2));
+        int body = r_reg(opcode, 0, reg2, 0,  reg1, self >= 32 ? reg1: self);
+        enc.add4(body);
+    }
+
+    public static void r_reg_subs(Encoding enc, Node n, int opcode) {
+        short reg1 = enc.reg(n.in(1));
+        short reg2 = enc.reg(n.in(2));
+        // 31 = 11111
+        int body = r_reg(opcode, 0, reg2, 0,  reg1, 31);
+        enc.add4(body);
+    }
+
+    public static int shift_reg(int opcode, int rm, int op2, int rn, int rd) {
+        assert 0 <= rn && rn < 32;
+        assert 0 <= rm && rm < 32;
+        assert 0 <= rd && rd < 32;
+        return (opcode << 21) | (rm << 16) | (op2 << 10) | (rn << 5) | rd;
+    }
+    public static void shift_reg(Encoding enc, Node n, int op2) {
+        short self = enc.reg(n);
+        short reg1 = enc.reg(n.in(1));
+        short reg2 = enc.reg(n.in(2));
+        int body = shift_reg(0b10011010110, reg2, op2, reg1, self);
+        enc.add4(body);
+    }
+
+    //  MUL can be considered an alias for MADD with the third operand Ra being set to 0
+    public static int madd(int opcode, int rm, int ra, int rn, int rd) {
+        assert 0 <= rn && rn < 32;
+        assert 0 <= rd && rd < 32;
+        assert 0 <= rm && rm < 32;
+        return (opcode << 21) | (rm << 16) | (ra << 10) | (rn << 5) | rd;
+    }
+    public static void madd(Encoding enc, Node n, int opcode, int ra) {
+        short self = enc.reg(n);
+        short reg1 = enc.reg(n.in(1));
+        short reg2 = enc.reg(n.in(2));
+        int body = madd(opcode, reg2, ra,  reg1, self);
+        enc.add4(body);
+    }
+
+    // encodes movk, movn, and movz
+    public static int mov(int opcode, int shift, int imm16, int rd) {
+        assert 0 <= rd && rd < 32;
+        return (opcode << 23) | (shift << 21) | (imm16 << 5) | rd;
+    }
+
+    public static int mov_reg(int opcode, int src, int rd) {
+        assert 0 <= rd && rd < 32;
+        return (opcode  << 21) | (src << 16) | 0b11111 << 5 | rd;
+    }
+
+    public static int ret(int opcode) {
+        return (opcode << 10);
+    }
+
+    // FMOV (scalar, immediate)
+    public static int f_scalar(int opcode, int ftype, int rm, int op, int rn, int rd) {
+        assert 0 <= rn && rn < 32;
+        assert 0 <= rd && rd < 32;
+        assert 0 <= rm && rm < 32;
+        return (opcode << 24) | (ftype << 22) | (1 << 21) | (rm << 16) | (op << 10) | (rn << 5) | rd;
+    }
+
+    public static int f_mov_reg(int opcode, int rn, int rd) {
+        assert 0 <= rn && rn < 32;
+        assert 0 <= rd && rd < 32;
+        return (opcode << 24) | (0b01100000010000 << 10) | (rn << 5) | rd;
+    }
+    public static int f_mov_general(int opcode, int ftype, int rmode, int opcode1, int rn, int rd) {
+        assert 0 <= rn && rn < 32;
+        assert 0 <= rd && rd < 32;
+        return (opcode << 24) |(ftype << 22) | (1 << 21) | (rmode << 19) | (opcode1 << 16) | (rn << 5) | rd;
+    }
+    public static void f_scalar(Encoding enc, Node n, int op ) {
+        short self = (short)(enc.reg(n)      -D_OFFSET);
+        short reg1 = (short)(enc.reg(n.in(1))-D_OFFSET);
+        short reg2 = (short)(enc.reg(n.in(2))-D_OFFSET);
+        int body = f_scalar(0b00011110, 1, reg2, op,  reg1, self);
+        enc.add4(body);
+    }
+
+    // share same encoding with LDR (literal, SIMD&FP) flavour
+    public static int load_pc(int opcode, int offset, int rt) {
+        offset>>=2;
+        return (opcode << 24) | (offset << 5) | rt;
+    }
+    // int l
+    public static int adrp(int op, int imlo,int opcode, int imhi, int rd) {
+        assert 0 <= rd && rd < 32;
+        return (op << 31) | (imlo << 29) |(opcode << 24) | (imhi << 5) | rd;
+    }
+
+    // [Rptr+Roff]
+    public static int indr_adr(int opcode, int off, STORE_LOAD_OPTION option, int s, int ptr, int rt) {
+        assert 0 <= ptr && ptr < 32;
+        assert 0 <= rt &&  rt  < 32;
+        return (opcode << 21) | (off << 16) | (option.ordinal() << 13) | (s << 12) | (2 << 10) | (ptr << 5) | rt;
+    }
+    // [Rptr+imm9]
+    public static int load_str_imm(int opcode, int imm12, int ptr, int rt, int size) {
+        assert 0 <= ptr && ptr < 32;
+        assert 0 <= rt &&  rt  < 32;
+
+        if(size == 8) imm12 = imm12 >> 3;
+        if(size == 4) imm12 = imm12 >> 2;
+        if(size == 2) imm12 = imm12 >> 1;
+        // size == 1  imm12 = imm12
+        return (opcode << 22) | ((imm12) << 10)  | (ptr << 5) | rt;
+    }
+
+    // encoding for vcvt, size is encoded in operand
+    // <Qd>, <Qm>
+    // F32.S32
+    //encoded as op = 0b00, size = 0b10.
+    // VCVT<c>.<Td>.<Tm> <Dd>, <Dm>
+    // opcode is broken down into 4 pieces
+    public static int f_convert(int opcode_1, int opcode_2, int opcode_3, int opcode_4,  int vd, int vm)  {
+        return (opcode_1 << 28) | (opcode_2 << 24) | (opcode_3 << 20) | (opcode_4 << 16) |
+                (vd << 12) | (0x01100010 << 4) | vm;
+    }
+    public static int float_cast(int opcode, int ftype, int rn, int rd) {
+        assert 0 <= rd &&  rd < 32;
+        assert 0 <= rn &&  rn  < 32;
+        return (opcode << 24) | (ftype << 22) | (2176 << 10) | (rn << 5) | rd;
+    }
+
+
+    // ftype = 3
+    public static int f_cmp(int opcode, int ftype, int rm, int rn) {
+        assert 0 <= rn && rn  < 32;
+        assert 0 <= rm && rm  < 32;
+        // Todo: |8 is not needed
+        return (opcode  << 24) | (ftype << 21) | (rm << 16) | (8 << 10) | (rn << 5);
+    }
+    public static void f_cmp(Encoding enc, Node n) {
+        short reg1 = (short)(enc.reg(n.in(1))-D_OFFSET);
+        short reg2 = (short)(enc.reg(n.in(2))-D_OFFSET);
+        int body = f_cmp(0b00011110, 3, reg1,  reg2);
+        enc.add4(body);
+    }
+
+    public static COND make_condition(String bop) {
+        return switch (bop) {
+        case "==" -> COND.EQ;
+        case "!=" -> COND.NE;
+        case "<"  -> COND.LT;
+        case "<=" -> COND.LE;
+        case ">=" -> COND.GE;
+        case ">"  -> COND.GT;
+        default   -> throw Utils.TODO();
+        };
+    }
+
+    public static int b_cond(int opcode, int delta, COND cond) {
+        // 24-5 == 19bits offset range
+        assert -(1<<19) <= delta && delta < (1<<19);
+        assert (delta&3)==0;
+        delta>>=2;
+        delta &= (1L<<19)-1;    // Zero extend
+        return (opcode << 24) | ((delta)<< 5) | cond.ordinal();
+    }
+
+    public static int cond_set(int opcode, int rm, COND cond, int rn, int rd) {
+        assert 0 <= rd &&  rd < 32;
+        assert 0 <= rn &&  rn  < 32;
+        return (opcode << 21) | (rm << 16) | (cond.ordinal() << 12) | (rn << 5) | rd;
+    }
+
+    // Branch with Link to Register calls a subroutine at an address in a register, setting register X30 to PC+4.
+    public static int blr(int opcode, int rd) {
+        assert 0 <= rd && rd < 32;
+        return opcode << 10 | rd << 5;
+    }
+    public static int b(int opcode, int delta) {
+        assert -(1<<26) <= delta && delta < (1<<26);
+        assert (delta&3)==0;
+        delta>>=2;
+        delta &= (1L<<26)-1;    // Zero extend
+        return (opcode << 26) | delta;
+    }
+    // no aligned assert(assert (delta&3)==0;)
+    public static int b_calloc(int opcode, int delta) {
+        assert -(1<<26) <= delta && delta < (1<<26);
+        delta>>=2;
+        delta &= (1L<<26)-1;    // Zero extend
+        return (opcode << 26) | delta;
+    }
+
+    @Override public RegMask callArgMask(TypeFunPtr tfp, int idx, int maxArgSlot ) { return callInMask(tfp,idx,maxArgSlot); }
+    static RegMask callInMask(TypeFunPtr tfp, int idx, int maxArgSlot ) {
+        if( idx==0 ) return CodeGen.CODE._rpcMask;
         if( idx==1 ) return null;
         // Count floats in signature up to index
         int fcnt=0;
         for( int i=2; i<idx; i++ )
-            if( tfp.arg(i-2) instanceof TypeFloat )
+            if( tfp.arg(i-2) instanceof TypeFloat)
                 fcnt++;
         // Floats up to XMMS in XMM registers
         if( tfp.arg(idx-2) instanceof TypeFloat ) {
@@ -125,121 +584,119 @@ public class arm extends Machine {
         throw Utils.TODO(); // Pass on stack slot
     }
 
-    static final long CALLEE_SAVE =
+    public static long decodeImm12(int imm12) {
+        int immr = (imm12 >> 6) & 0x3F;
+        int imms = imm12 & 0x3F;
+        int size;
+        if ((imm12 & 0x1000) != 0) {
+            size = 64;
+        } else {
+            size = 31-(imms >> 1);
+            size |= size >> 1;
+            size |= size >> 2;
+            size |= size >> 4;
+            size++;
+            imms &= ~((32-size) << 1);
+        }
+        long val = (2L << imms)-1;
+        while (size < 64) {
+            val |= val << size;
+            size <<= 1;
+        }
+        val = (val >>> immr) | val << (64-immr);
+        return val;
+    }
+
+    // Return the max stack slot used by this signature, or 0
+    @Override public short maxArgSlot( TypeFunPtr tfp ) {
+        int icnt=0, fcnt=0;     // Count of ints, floats
+        for( int i=0; i<tfp.nargs(); i++ ) {
+            if( tfp.arg(i) instanceof TypeFloat ) fcnt++;
+            else icnt++;
+        }
+        int nstk = Math.max(icnt-8,0)+Math.max(fcnt-8,0);
+        return (short)nstk;
+    }
+
+    private static final long CALLEE_SAVE =
         1L<<X19 |
         1L<<X20 | 1L<<X21 | 1L<<X22 | 1L<<X23 |
         1L<<X24 | 1L<<X25 | 1L<<X26 | 1L<<X27 |
         1L<<X28 |
         1L<<D9  | 1L<<D10 | 1L<<D11 |
         1L<<D12 | 1L<<D13 | 1L<<D14 | 1L<<D15;
-
-    static final RegMask CALLER_SAVE_MASK;
-    static {
-        long caller = ~CALLEE_SAVE;
-        caller &= ~(1L<<RSP);
-        CALLER_SAVE_MASK = new RegMask(caller,1L<<(FLAGS-64));
-    }
-    static RegMask armCallerSave() { return CALLER_SAVE_MASK; }
-    @Override public RegMask callerSave() { return armCallerSave(); }
-
-    static final RegMask CALLEE_SAVE_MASK = new RegMask(CALLEE_SAVE);
-    static RegMask armCalleeSave() { return CALLEE_SAVE_MASK; }
-    @Override public RegMask calleeSave() { return armCalleeSave(); }
-
-
-    // Return single int/ptr register.  Used by CallEnd output and Return input.
-    static final RegMask[] RET_MASKS;
-    static {
-        int nSaves = CALLEE_SAVE_MASK.size();
-        RET_MASKS = new RegMask[4 + nSaves];
-        RET_MASKS[0] = null;
-        RET_MASKS[1] = null;     // Memory
-        RET_MASKS[2] = null;     // Varies, either XMM0 or RAX
-        RET_MASKS[3] = RMASK;    // Expected R30 but could be any register
-        short reg = CALLEE_SAVE_MASK.firstReg();
-        for( int i=0; i<nSaves; i++ ) {
-            RET_MASKS[i+4] = new RegMask(reg);
-            reg = CALLEE_SAVE_MASK.nextReg(reg);
-        }
-    }
-    static RegMask retMask( TypeFunPtr tfp, int i ) {
-        return i==2
-            ? (tfp.ret() instanceof TypeFloat ? D0_MASK : X0_MASK)
-            : RET_MASKS[i];
+    static final long CALLER_SAVE = ~CALLEE_SAVE & ~(1L<<RSP);
+    @Override public long callerSave() { return CALLER_SAVE; }
+    @Override public long neverSave() { return 1L<<RSP; }
+    @Override public RegMask retMask( TypeFunPtr tfp ) {
+        return tfp.ret() instanceof TypeFloat ? D0_MASK : X0_MASK;
     }
+    @Override public int rpc() { return X30; }
 
     // Create a split op; any register to any register, including stack slots
     @Override public SplitNode split(String kind, byte round, LRG lrg) {  return new SplitARM(kind,round);  }
 
     // Return a MachNode unconditional branch
     @Override public CFGNode jump() {
-        throw Utils.TODO();
-    }
-
-    // Break an infinite loop
-    @Override public IfNode never( CFGNode ctrl ) {
-        throw Utils.TODO();
+        return new UJmpARM();
     }
 
     // Instruction selection
-    @Override public Node instSelect( Node n ) {
+    @Override public Node instSelect(Node n ) {
         return switch( n ) {
-        case AddFNode     addf  -> addf(addf);
-        case AddNode      add   -> add(add);
-        case AndNode      and   -> and(and);
-        case BoolNode     bool  -> cmp(bool);
-        case CallNode     call  -> call(call);
-        case CastNode     cast  -> new CastNode(cast);
-        case CallEndNode  cend  -> new CallEndARM(cend);
-        case CProjNode    c     -> new CProjNode(c);
-        case ConstantNode con   -> con(con);
-        case DivFNode     divf  -> new DivFARM(divf);
-        case DivNode      div   -> new DivARM(div);
-        case FunNode      fun   -> new FunARM(fun);
-        case IfNode       iff   -> jmp(iff);
-        case LoadNode     ld    -> ld(ld);
-        case MemMergeNode mem   -> new MemMergeNode(mem);
-        case MulFNode     mulf  -> new MulFARM(mulf);
-        case MulNode      mul   -> mul(mul);
-        case NewNode      nnn   -> new NewARM(nnn);
-        case OrNode       or   ->  or(or);
-        case ParmNode     parm  -> new ParmARM(parm);
-        case PhiNode      phi   -> new PhiNode(phi);
-        case ProjNode     prj   -> prj(prj);
+        case AddFNode addf  -> new AddFARM(addf);
+        case AddNode add    -> add(add);
+        case AndNode and    -> and(and);
+        case BoolNode bool  -> cmp(bool);
+        case CallNode call  -> call(call);
+        case CastNode cast  -> new CastARM(cast);
+        case CallEndNode cend -> new CallEndARM(cend);
+        case CProjNode c    -> new CProjNode(c);
+        case ConstantNode con -> con(con);
+        case DivFNode divf  -> new DivFARM(divf);
+        case DivNode div    -> new DivARM(div);
+        case FunNode fun    -> new FunARM(fun);
+        case IfNode iff     -> jmp(iff);
+        case LoadNode ld    -> ld(ld);
+        case MemMergeNode mem -> new MemMergeNode(mem);
+        case MinusNode neg  -> new NegARM(neg);
+        case MulFNode mulf  -> new MulFARM(mulf);
+        case MulNode mul    -> new MulARM(mul);
+        case NewNode nnn    -> new NewARM(nnn);
+        case NotNode not    -> new NotARM(not);
+        case OrNode or      -> or(or);
+        case ParmNode parm  -> new ParmARM(parm);
+        case PhiNode phi    -> new PhiNode(phi);
+        case ProjNode prj   -> new ProjARM(prj);
         case ReadOnlyNode read  -> new ReadOnlyNode(read);
-        case ReturnNode   ret   -> new RetARM(ret,ret.fun());
-        case SarNode      sar   -> sar(sar);
-        case ShlNode      shl   -> shl(shl);
-        case ShrNode      shr   -> shr(shr);
-        case StartNode    start -> new StartNode(start);
-        case StopNode     stop  -> new StopNode(stop);
-        case StoreNode    st    -> st(st);
-        case SubFNode     subf  -> new SubFARM(subf);
-        case SubNode      sub   -> sub(sub);
-        case ToFloatNode  tfn   -> i2f8(tfn);
-        case XorNode      xor   -> xor(xor);
-
-        case LoopNode     loop  -> new LoopNode(loop);
-        case RegionNode   region-> new RegionNode(region);
+        case ReturnNode ret -> new RetARM(ret,ret.fun());
+        case SarNode sar    -> asr(sar);
+        case ShlNode shl    -> lsl(shl);
+        case ShrNode shr    -> lsr(shr);
+        case StartNode start -> new StartNode(start);
+        case StopNode stop  -> new StopNode(stop);
+        case StoreNode st   -> st(st);
+        case SubFNode subf  -> new SubFARM(subf);
+        case SubNode sub    -> sub(sub);
+        case ToFloatNode tfn-> new I2F8ARM(tfn);
+        case XorNode xor    -> xor(xor);
+
+        case LoopNode  loop  -> new LoopNode(loop);
+        case RegionNode region-> new RegionNode(region);
         default -> throw Utils.TODO();
         };
     }
 
-    private Node mul(MulNode mul) {
-        Node rhs = mul.in(2);
-        if( rhs instanceof ConstantNode off && off._con instanceof TypeInteger toff ) {
-            return new MulIARM(mul, toff);
-        }
-        return new MulARM(mul);
-    }
     private Node cmp(BoolNode bool){
         Node cmp = _cmp(bool);
-        return new SetARM(cmp, bool.op());
+        return new SetARM(cmp, IfNode.negate(bool.op()));
     }
-
-    private Node i2f8(ToFloatNode tfn) {
-        assert tfn.in(1)._type instanceof TypeInteger ti;
-        return new I2F8ARM(tfn);
+    private Node _cmp(BoolNode bool) {
+        if( bool.isFloat() )
+            return new CmpFARM(bool);
+        return bool.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti
+                ? new CmpIARM(bool, (int)ti.value())
+                : new CmpARM(bool);
     }
 
     private Node ld(LoadNode ld) {
@@ -250,129 +707,101 @@ public class arm extends Machine {
         // If/Bool combos will match to a Cmp/Set which sets flags.
         // Most general arith ops will also set flags, which the Jmp needs directly.
         // Loads do not set the flags, and will need an explicit TEST
-        if( !(iff.in(1) instanceof BoolNode) )
-            iff.setDef(1,new BoolNode.EQ(iff.in(1),new ConstantNode(TypeInteger.ZERO)));
-        return new BranchARM(iff, ((BoolNode)iff.in(1)).op());
-    }
-
-    private Node _cmp(BoolNode bool) {
-        if( bool instanceof BoolNode.EQF ||
-                bool instanceof BoolNode.LTF ||
-                bool instanceof BoolNode.LEF )
-            return new CmpFARM(bool);
-
-
-        return bool.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti
-                ? new CmpIARM(bool, ti)
-                : new CmpARM(bool);
-    }
-
-
-    private Node addf(AddFNode addf) {
-        return new AddFARM(addf);
+        String op = "!=";
+        if( iff.in(1) instanceof BoolNode bool ) op = bool.op();
+        else if( iff.in(1)==null ) op = "=="; // Never-node cutout
+        else iff.setDef(1, new BoolNode.NE(iff.in(1), new ConstantNode(TypeInteger.ZERO)));
+        return new BranchARM(iff, op);
     }
 
     private Node add(AddNode add) {
-        Node rhs = add.in(2);
-        if( rhs instanceof ConstantNode off && off._con instanceof TypeInteger toff ) {
-            return new AddIARM(add, toff);
-        }
-        return new AddARM(add);
+        return add.in(2) instanceof ConstantNode off && off._con instanceof TypeInteger ti && imm12(ti)
+                ? new AddIARM(add, (int)ti.value())
+                : new AddARM(add);
     }
 
     private Node sub(SubNode sub) {
-        return sub.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti
-                ? new AddIARM(sub, TypeInteger.constant(-ti.value()))
+        return sub.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti)
+                ? new SubIARM(sub, (int)(ti.value()))
                 : new SubARM(sub);
     }
 
-    private Node and(AndNode and) {
-        if( and.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti )
-            return new AndIARM(and, ti);
-        return new AndARM(and);
-    }
-
-    private Node or(OrNode or) {
-        if(or.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti)
-            return new OrIARM(or, ti);
-
-        return new OrARM(or);
-    }
-
-    private Node xor(XorNode xor) {
-        if(xor.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti)
-            return new XorIARM(xor, ti);
-        return new XorARM(xor);
-    }
-
-    private Node con(ConstantNode con) {
+    private Node con( ConstantNode con ) {
         if( !con._con.isConstant() ) return new ConstantNode( con ); // Default unknown caller inputs
         return switch( con._con ) {
             case TypeInteger ti  -> new IntARM(con);
             case TypeFloat   tf  -> new FloatARM(con);
             case TypeFunPtr  tfp -> new TFPARM(con);
-            case TypeMemPtr  tmp -> new ConstantNode(con);
-            case TypeNil     tn  -> throw Utils.TODO();
+            case TypeMemPtr tmp -> new ConstantNode(con);
+            case TypeNil tn  -> throw Utils.TODO();
             // TOP, BOTTOM, XCtrl, Ctrl, etc.  Never any executable code.
-            case Type t -> new ConstantNode(con);
+            case Type t -> t==Type.NIL ? new IntARM(con) : new ConstantNode(con);
         };
     }
 
-    private Node sar(SarNode sar){
-        if( sar.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti)
-            return new AsrIARM(sar, ti);
-        return new AsrARM(sar);
+    private Node call(CallNode call){
+        return call.fptr() instanceof ConstantNode con && con._con instanceof TypeFunPtr tfp
+                ? new CallARM(call, tfp)
+                : new CallRRARM(call);
+    }
+
+    private Node or(OrNode or) {
+        int imm12;
+        return or.in(2) instanceof ConstantNode off && off._con instanceof TypeInteger ti && (imm12 = imm12Logical(ti)) != -1
+                ? new OrIARM(or, imm12)
+                : new OrARM(or);
     }
 
-    private Node shl(ShlNode shl) {
-        if( shl.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti)
-            return new LslIARM(shl, ti);
-        return new LslARM(shl);
+    private Node xor(XorNode xor) {
+        int imm12;
+        return xor.in(2) instanceof ConstantNode off && off._con instanceof TypeInteger ti && (imm12 = imm12Logical(ti)) != -1
+                ? new XorIARM(xor, imm12)
+                : new XorARM(xor);
+    }
 
+    private Node and(AndNode and) {
+        int imm12;
+        return and.in(2) instanceof ConstantNode off && off._con instanceof TypeInteger ti && (imm12 = imm12Logical(ti)) != -1
+                ? new AndIARM(and, imm12)
+                : new AndARM(and);
     }
 
-    private Node shr(ShrNode shr) {
-        if( shr.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti)
-            return new LsrIARM(shr, ti);
-        return new LsrARM(shr);
+    private Node asr(SarNode asr) {
+        return asr.in(2) instanceof ConstantNode off && off._con instanceof TypeInteger ti && ti.value() >= 0 && ti.value() < 63
+                ? new AsrIARM(asr, (int)ti.value())
+                : new AsrARM(asr);
     }
 
-    private Node call(CallNode call){
-        if(call.fptr() instanceof ConstantNode con && con._con instanceof TypeFunPtr tfp)
-            return new CallARM(call, tfp);
-        return new CallRRARM(call);
+    private Node lsl(ShlNode lsl) {
+        return lsl.in(2)  instanceof ConstantNode off && off._con instanceof TypeInteger ti && ti.value() >= 0 && ti.value() < 63
+                ? new LslIARM(lsl, (int)ti.value())
+                : new LslARM(lsl);
     }
 
-    private Node prj(ProjNode prj) {
-        return new ProjARM(prj);
+    private Node lsr(ShrNode lsr) {
+        return lsr.in(2)  instanceof ConstantNode off && off._con instanceof TypeInteger ti && ti.value() >= 0 && ti.value() < 63
+                ? new LsrIARM(lsr, (int)ti.value())
+                : new LsrARM(lsr);
     }
 
 
     private static int off;
     private static Node idx;
     private Node st(StoreNode st) {
-        int imm=0;
-        Node xval = st.val();
-        // e.g store this                     s.cs[0] =  67; // C
-        if( xval instanceof ConstantNode con && con._con instanceof TypeInteger ti ) {
-            xval = null;
-            imm = (int)ti.value();
-            assert imm == ti.value(); // In 32-bit range
-        }
-        return new StoreARM(address(st),st.ptr(),idx,off,imm,xval);
+        return new StoreARM(address(st),st.ptr(),idx,off,st.val());
     }
 
     // Gather addressing mode bits prior to constructing.  This is a builder
     // pattern, but saving the bits in a *local* *global* here to keep mess
     // contained.
-    private <N extends MemOpNode> N address( N mop ) {
+    private <N extends MemOpNode> N address(N mop ) {
         off = 0;  // Reset
         idx = null;
         Node base = mop.ptr();
         // Skip/throw-away a ReadOnly, only used to typecheck
         if( base instanceof ReadOnlyNode read ) base = read.in(1);
         assert !(base instanceof AddNode) && base._type instanceof TypeMemPtr; // Base ptr always, not some derived
-        if( mop.off() instanceof ConstantNode con && con._con instanceof TypeInteger ti ) {
+        if( mop.off() instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm9(ti) ) {
             off = (int)ti.value();
             assert off == ti.value(); // In 32-bit range
         } else {
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/arm/i2f8.java b/src/main/java/com/seaofnodes/simple/node/cpus/arm/i2f8.java
deleted file mode 100644
index e0792669..00000000
--- a/src/main/java/com/seaofnodes/simple/node/cpus/arm/i2f8.java
+++ /dev/null
@@ -1,4 +0,0 @@
-package com.seaofnodes.simple.node.cpus.arm;
-
-public class i2f8 {
-}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AUIPC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AUIPC.java
new file mode 100644
index 00000000..37383608
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AUIPC.java
@@ -0,0 +1,41 @@
+package com.seaofnodes.simple.node.cpus.riscv;
+
+import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.ConstantNode;
+import com.seaofnodes.simple.node.MachNode;
+import com.seaofnodes.simple.type.Type;
+
+// Add upper 20bits to PC.  Immediate comes from the relocation info.
+public class AUIPC extends ConstantNode implements MachNode, RIPRelSize {
+    AUIPC( Type tfp ) { super(tfp); }
+    @Override public RegMask regmap(int i) { return null; }
+    @Override public RegMask outregmap() { return riscv.WMASK; }
+    @Override public boolean isClone() { return true; }
+    @Override public AUIPC copy() { return new AUIPC(_con); }
+    @Override public String op() { return "auipc"; }
+    @Override public void encoding( Encoding enc ) {
+        enc.relo(this);
+        short dst = enc.reg(this);
+        enc.add4(riscv.u_type(riscv.OP_AUIPC, dst, 0));
+    }
+
+    // Delta is from opcode start, but X86 measures from the end of the 5-byte encoding
+    @Override public byte encSize(int delta) { return 4; }
+
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        //short rpc = enc.reg(this);
+        //// High half is where the TFP constant used to be, the last input
+        //short auipc = enc.reg(in(_inputs._len-1));
+        //enc.patch4(opStart,riscv.i_type(0x67, rpc, 0, auipc, delta));
+        throw Utils.TODO();
+    }
+
+    @Override public void asm(CodeGen code, SB sb) {
+        String reg = code.reg(this);
+        sb.p(reg).p(" = PC+#");
+        if( _con == null ) sb.p("---");
+        else _con.print(sb);
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AddFRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AddFRISC.java
index 2417aeb6..4d2ac916 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AddFRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AddFRISC.java
@@ -1,30 +1,17 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
-public class AddFRISC extends MachConcreteNode implements MachNode{
+// fadd.d
+public class AddFRISC extends MachConcreteNode implements MachNode {
     AddFRISC(Node addf) {super(addf);}
-
-    // Register mask allowed on input i.
+    @Override public String op() { return "addf"; }
     @Override public RegMask regmap(int i) { assert i==1 || i==2; return riscv.FMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return riscv.FMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // Default on double precision for now(64 bits)
-    // General form: "fadd.d  rd = src1 + src2
+    @Override public void encoding( Encoding enc ) { riscv.rf_type(enc,this,riscv.RM.RNE,1); }
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" + ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "addf"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AddIRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AddIRISC.java
index e92a7b08..a85ce5d0 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AddIRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AddIRISC.java
@@ -4,8 +4,18 @@ import com.seaofnodes.simple.Utils;
 import com.seaofnodes.simple.node.Node;
 
 public class AddIRISC extends ImmRISC {
-    AddIRISC( Node add, int imm ) { super(add,imm); }
-    @Override int opcode() { throw Utils.TODO(); }
-    @Override public String glabel() { return "+"; }
+    // Used to inst-selection as a direct match against an ideal Add/Sub
+    public AddIRISC( Node add, int imm12, boolean pop ) { super(add,imm12,pop); }
     @Override public String op() { return "addi"; }
+    @Override public String glabel() { return "+"; }
+    @Override int opcode() {  return riscv.OP_IMM; }
+    @Override int func3() {return 0;}
+    @Override public AddIRISC copy() {
+        // Clone the AddI, using the same inputs-only code used during inst select.
+        // Output edges are missing.
+        AddIRISC add = new AddIRISC(in(1),_imm12,false);
+        // Copys happen when output edges should be valid, so correct missing output edges.
+        in(1)._outputs.add(add);
+        return add;
+    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AddRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AddRISC.java
index 344c217d..df392a0e 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AddRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AddRISC.java
@@ -1,29 +1,21 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class AddRISC extends MachConcreteNode implements MachNode {
-    AddRISC( Node add) {super(add); }
+    public AddRISC( Node add ) { super(add); }
+    AddRISC( Node base, Node off ) {
+        super(new Node[3]);
+        _inputs.set(1,base);
+        _inputs.set(2,off );
+    }
     @Override public String op() { return "add"; }
-
-    // Register mask allowed on input i.
     @Override public RegMask regmap(int i) { return riscv.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return riscv.WMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form: "rd = rs1 + rs2"
+    @Override public void encoding( Encoding enc ) { riscv.r_type(enc,this,0,0);  }
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" + ").p(code.reg(in(2)));
     }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AndIRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AndIRISC.java
index ddbf5aa4..ba88bb48 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AndIRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AndIRISC.java
@@ -4,8 +4,9 @@ import com.seaofnodes.simple.Utils;
 import com.seaofnodes.simple.node.Node;
 
 public class AndIRISC extends ImmRISC {
-    AndIRISC( Node and, int imm) { super(and,imm); }
-    @Override int opcode() { throw Utils.TODO(); }
-    @Override public String glabel() { return "&"; }
+    public AndIRISC( Node and, int imm) { super(and,imm); }
     @Override public String op() { return "andi"; }
+    @Override public String glabel() { return "&"; }
+    @Override int opcode() {  return riscv.OP_IMM; }
+    @Override int func3() {return 7;}
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AndRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AndRISC.java
index ca00bc98..93ef95c0 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AndRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/AndRISC.java
@@ -1,37 +1,15 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
-import java.lang.StringBuilder;
 
-public class AndRISC extends MachConcreteNode implements MachNode{
-    AndRISC(Node and) {
-        super(and);
-    }
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        assert i==1 || i==2;
-        return riscv.RMASK;
-    }
-
-    // Register mask allowed as a result.  0 for no register.
+public class AndRISC extends MachConcreteNode implements MachNode {
+    public AndRISC(Node and) { super(and); }
+    @Override public String op() { return "and"; }
+    @Override public RegMask regmap(int i) { return riscv.RMASK; }
     @Override public RegMask outregmap() { return riscv.WMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form:  #rd = rs1 & rs2
+    @Override public void encoding( Encoding enc ) { riscv.r_type(enc,this,0b111,0);  }
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" & ").p(code.reg(in(2)));
     }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/BranchRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/BranchRISC.java
index 6a1cf7dc..44ff4e8b 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/BranchRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/BranchRISC.java
@@ -1,47 +1,92 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import java.io.ByteArrayOutputStream;
 import java.util.BitSet;
 
 // Conditional branch such as: BEQ
-public class BranchRISC extends IfNode implements MachNode {
-    final String _bop;
+public class BranchRISC extends IfNode implements MachNode, RIPRelSize {
+    String _bop;
     // label is obtained implicitly
-    BranchRISC( IfNode iff, String bop, Node n1, Node n2 ) {
+    public BranchRISC( IfNode iff, String bop, Node n1, Node n2 ) {
         super(iff);
         _bop = bop;
         _inputs.setX(1,n1);
         _inputs.setX(2,n2);
     }
 
+    @Override public String op() { return "b"+_bop; }
     @Override public String label() { return op(); }
-
+    @Override public String comment() { return "L"+cproj(1)._nid; }
     @Override public RegMask regmap(int i) { return riscv.RMASK; }
     @Override public RegMask outregmap() { return null; }
+    @Override public void negate() {
+        _bop = negate(_bop);
+        // Cannot encode ">" or "<=", so flip these
+        if( _bop.equals(">") || _bop.equals("<=") ) {
+            swap12();           // Cannot negate the test, so swap the operands
+            _bop = swap(_bop);  // Swap test to match
+        }
+    }
 
     @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) {
-        in(1)._print0(sb.append("if( "),visited).append(_bop);
+        sb.append("if( ");
+        if( in(1)==null ) sb.append("0");
+        else in(1)._print0(sb,visited);
+        sb.append(_bop);
         if( in(2)==null ) sb.append("0");
         else in(2)._print0(sb,visited);
         return sb.append(" )");
     }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        if( in(1)==null && _bop=="!=" ) return; // Inverted never-node, no code
+        enc.jump(this,cproj(0));
+        if( in(1)==null )       // Never node
+            enc.add4(riscv.j_type(riscv.OP_JAL, 0, 0));
+        else {
+            // Todo: relocs (for offset - immf)
+            short src1 = enc.reg(in(1));
+            short src2 = in(2)==null ? (short)riscv.ZERO : enc.reg(in(2));
+            enc.add4(riscv.b_type(riscv.OP_BRANCH, riscv.jumpop(_bop), src1, src2, 0));
+        }
     }
 
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(in(1))).p(" ").p(_bop).p(" ").p(in(2)==null ? "#0" : code.reg(in(2)));
+    // Delta is from opcode start
+    @Override public byte encSize(int delta) {
+        if( in(1)==null && _bop=="!=" ) return 0; // Inverted never-node, no code
+        if( -4*1024 <= delta && delta < 4*1024 ) return 4;
+        // 2 word encoding needs a tmp register, must teach RA
+        throw Utils.TODO();
     }
 
-    @Override public String op() { return "b"+_bop; }
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        assert !( in(1)==null && _bop=="!=" ); // Inverted never-node, no code no patch
+        if( in(1)==null ) {     // Never node
+            enc.patch4(opStart,riscv.j_type(riscv.OP_JAL, 0, delta));
+        } else {
+            short src1 = enc.reg(in(1));
+            short src2 = in(2)==null ? (short)riscv.ZERO : enc.reg(in(2));
+            if( opLen==4 ) {
+                enc.patch4(opStart,riscv.b_type(riscv.OP_BRANCH, riscv.jumpop(_bop), src1, src2, delta));
+            } else {
+                throw Utils.TODO();
+            }
+        }
+    }
 
-    @Override public String comment() {
-        return "L"+cproj(1)._nid+", L"+cproj(0)._nid;
+    @Override public void asm(CodeGen code, SB sb) {
+        if( in(1)==null && _bop=="!=" ) {
+            sb.p("never");
+            return;
+        }
+        String src1 = in(1)==null ? "#0" : code.reg(in(1));
+        String src2 = in(2)==null ? "#0" : code.reg(in(2));
+        sb.p(src1).p(" ").p(_bop).p(" ").p(src2).p(" ");
+        CFGNode prj = cproj(0).uctrlSkipEmpty();
+        if( !prj.blockHead() ) prj = prj.cfg0();
+        sb.p(label(prj));
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallEndRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallEndRISC.java
index fd1ba7c3..7df68e77 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallEndRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallEndRISC.java
@@ -1,35 +1,8 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.node.CallEndNode;
 import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.type.TypeFloat;
-import com.seaofnodes.simple.type.TypeFunPtr;
-import java.io.ByteArrayOutputStream;
 
 public class CallEndRISC extends CallEndNode implements MachNode {
-    final TypeFunPtr _tfp;
-    CallEndRISC( CallEndNode cend ) {
-        super(cend);
-        _tfp = (TypeFunPtr)(cend.call().fptr()._type);
-    }
-
-    @Override public String label() { return op(); }
-    @Override public RegMask regmap(int i) { return null; }
-    @Override public RegMask outregmap() { return null; }
-    @Override public RegMask outregmap(int idx) { return idx == 2 ? riscv.retMask(_tfp,2) : null; }
-    @Override public RegMask killmap() { return riscv.riscCallerSave(); }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    @Override public void asm(CodeGen code, SB sb) {  }
-
-    @Override public String op() { return "cend"; }
-
+    CallEndRISC( CallEndNode cend ) { super(cend); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRISC.java
index 54f4fba9..7a0f3313 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRISC.java
@@ -1,44 +1,58 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.TypeFunPtr;
-import java.io.ByteArrayOutputStream;
 
-public class CallRISC extends CallNode implements MachNode{
+public class CallRISC extends CallNode implements MachNode, RIPRelSize {
     final TypeFunPtr _tfp;
     final String _name;
-
     CallRISC( CallNode call, TypeFunPtr tfp ) {
         super(call);
-        _inputs.pop(); // Pop constant target
         assert tfp.isConstant();
+        _inputs.pop(); // Pop constant target
         _tfp = tfp;
         _name = CodeGen.CODE.link(tfp)._name;
     }
 
+    @Override public String op() { return "call"; }
     @Override public String label() { return op(); }
     @Override public RegMask regmap(int i) {
-        return riscv.callInMask(_tfp,i); // Normal argument
+        return riscv.callInMask(_tfp,i,fun()._maxArgSlot);
     }
-    @Override public RegMask outregmap() { return null; }
-
+    @Override public RegMask outregmap() { return riscv.RPC_MASK; }
     @Override public String name() { return _name; }
     @Override public TypeFunPtr tfp() { return _tfp; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
+    @Override public void encoding( Encoding enc ) {
+        // Short form +/-4K:  beq r0,r0,imm12
+        // Long form:  auipc rX,imm20/32; jal r0,[rX+imm12/32]
+        enc.relo(this);
+        enc.add4(riscv.j_type(riscv.OP_JAL, riscv.RPC, 0));
+    }
+
+    // Delta is from opcode start
+    @Override public byte encSize(int delta) {
+        if( -(1L<<20) <= delta && delta < (1L<<20) ) return 4;
+        // 2 word encoding needs a tmp register, must teach RA
         throw Utils.TODO();
     }
 
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        if( opLen==4 ) {
+            enc.patch4(opStart,riscv.j_type(riscv.OP_JAL, riscv.RPC, delta));
+        } else {
+            throw Utils.TODO();
+        }
+    }
+
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(_name).p("  ");
         for( int i=0; i<nargs(); i++ )
-            sb.p(code.reg(arg(i))).p("  ");
-        sb.unchar(2);
-    }
+            sb.p(code.reg(arg(i+2))).p(", ");
+        sb.unchar(2).p("  ").p(code.reg(fptr()));
 
-    @Override public String op() { return "call"; }
+    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRRISC.java
index 3bae656d..dcc53cbf 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallRRISC.java
@@ -1,26 +1,25 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import java.io.ByteArrayOutputStream;
 
-public class CallRRISC extends CallNode implements MachNode{
+public class CallRRISC extends CallNode implements MachNode {
     CallRRISC( CallNode call ) { super(call); }
-
+    @Override public String op() { return "callr"; }
     @Override public String label() { return op(); }
     @Override public RegMask regmap(int i) {
-        // Todo: float or int?
-        return i==_inputs._len
+        return i==_inputs._len-1
             ? riscv.RMASK                // Function call target
-            : riscv.callInMask(tfp(),i); // Normal argument
+            : riscv.callInMask(tfp(),i,fun()._maxArgSlot); // Normal argument
     }
     @Override public RegMask outregmap() { return null; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        short rpc = enc.reg(this);
+        short src = enc.reg(in(_inputs._len-1));
+        int body = riscv.i_type(riscv.OP_JALR, rpc, 0, src, 0);
+        enc.add4(body);
     }
 
     @Override public void asm(CodeGen code, SB sb) {
@@ -29,7 +28,4 @@ public class CallRRISC extends CallNode implements MachNode{
             sb.p(code.reg(arg(i))).p("  ");
         sb.unchar(2);
     }
-
-    @Override public String op() { return "callr"; }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CastRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CastRISC.java
index a0d0df90..c404aaa5 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CastRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CastRISC.java
@@ -2,17 +2,17 @@ package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.node.CastNode;
 import com.seaofnodes.simple.node.MachNode;
-import java.io.ByteArrayOutputStream;
 
 public class CastRISC extends CastNode implements MachNode {
-    CastRISC( CastNode cast ) { super(cast); }
+    public CastRISC( CastNode cast ) { super(cast); }
+    @Override public String op() { return label(); }
     @Override public RegMask regmap(int i) { assert i==1; return RegMask.FULL; }
     @Override public RegMask outregmap() { return RegMask.FULL; }
     @Override public int twoAddress( ) { return 1; }
-    @Override public int encoding(ByteArrayOutputStream bytes) { return 0; /*no encoding*/ }
+    @Override public void encoding( Encoding enc ) { }
     @Override public void asm(CodeGen code, SB sb) { _t.print(sb.p(code.reg(in(1))).p(" isa ")); }
-    @Override public String op() { return label(); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/DivFRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/DivFRISC.java
index d360bea6..c67d7b3d 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/DivFRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/DivFRISC.java
@@ -1,30 +1,19 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import java.io.ByteArrayOutputStream;
 
+// fdiv.d
 public class DivFRISC extends MachConcreteNode implements MachNode{
     DivFRISC(Node divf) {super(divf);}
-
-    // Register mask allowed on input i.
+    @Override public String op() { return "divf"; }
     @Override public RegMask regmap(int i) { assert i==1 || i==2; return riscv.FMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return riscv.FMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
+    @Override public void encoding( Encoding enc ) { riscv.rf_type(enc,this,riscv.RM.RUP,13); }
     // Default on double precision for now(64 bits)
     // General form: "fdiv.d  rd = src1 / src2
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" / ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "divf"; }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/DivRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/DivRISC.java
index ee49a883..8367ee68 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/DivRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/DivRISC.java
@@ -1,32 +1,17 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class DivRISC extends MachConcreteNode implements MachNode{
-    DivRISC(Node div) {super(div);}
-
-    // Register mask allowed on input i.
-    @Override public RegMask regmap(int i) {
-        assert i==1 || i==2;
-        return riscv.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
+    public DivRISC(Node div) {super(div);}
+    @Override public String op() { return "div"; }
+    @Override public RegMask regmap(int i) { return riscv.RMASK; }
     @Override public RegMask outregmap() { return riscv.WMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // Signed division
-    // General form: "rd  = rs1 / rs"
+    @Override public void encoding( Encoding enc ) { riscv.r_type(enc,this,4,1);  }
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" / ").p(code.reg(in(2)));
     }
 
-    @Override public String op() { return "div"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FltRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FltRISC.java
index 2832ac52..35de7e04 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FltRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FltRISC.java
@@ -2,30 +2,46 @@ package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.ConstantNode;
 import com.seaofnodes.simple.node.MachNode;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.type.TypeFloat;
 
-public class FltRISC extends ConstantNode implements MachNode{
-    FltRISC(ConstantNode con) { super(con);  }
-    @Override public String op() { return "flw"; }
-    // Register mask allowed on input i.  0 for no register.
+public class FltRISC extends ConstantNode implements MachNode, RIPRelSize {
+    FltRISC(ConstantNode con) { super(con); }
+    @Override public String op() { return "ld8"; }
     @Override public RegMask regmap(int i) { return null; }
-    // General int registers!  Must-split into the floats
-    @Override public RegMask outregmap() { return riscv.RMASK; }
+    @Override public RegMask outregmap() { return riscv.FMASK; }
+    @Override public boolean isClone() { return true; }
+    @Override public FltRISC copy() { return new FltRISC(this); }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        enc.largeConstant(this,_con, 0, -1/*TODO: RISC5 style patching*/);
+        short dst = (short)(enc.reg(this) - riscv.F_OFFSET);
+        short tmp = (short)riscv.T6;
+        // AUIPC dst,#hi20_constant_pool
+        enc.add4(riscv.u_type(riscv.OP_AUIPC, tmp, 0));
+        // Load dst,[dst+#low12_constant_pool]
+        enc.add4(riscv.i_type(riscv.OP_LOADFP, dst, 0b11, tmp, 0));
+    }
+    @Override public RegMask killmap() { return new RegMask(riscv.T6); }
+
+    // Delta is from opcode start.
+    // TODO: always size 8?
+    @Override public byte encSize(int delta) { return 8;  }
+
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        short dst = (short)(enc.reg(this) - riscv.F_OFFSET);
+        short tmp = (short)riscv.T6;
+        // AUIPC dst,#hi20_constant_pool
+        enc.patch4(opStart  , riscv.u_type(riscv.OP_AUIPC, tmp, delta>>12));
+        // Load dst,[dst+#low12_constant_pool]
+        enc.patch4(opStart+4, riscv.i_type(riscv.OP_LOADFP, dst, 0b11, tmp, delta & 0xFFF));
     }
 
-    // Human-readable form appended to the SB.  Things like the encoding,
-    // indentation, leading address or block labels not printed here.
-    // Just something like "ld4\tR17=[R18+12] // Load array base".
-    // General form: "op\tdst=src+src"
     @Override public void asm(CodeGen code, SB sb) {
-        _con.print(sb.p(code.reg(this)).p(" #"));
+        _con.print(sb.p(code.reg(this)).p(" = #"));
     }
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FunRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FunRISC.java
index 3b7d9a34..84f0f4c7 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FunRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FunRISC.java
@@ -1,21 +1,22 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
+import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.FunNode;
 import com.seaofnodes.simple.node.MachNode;
-import java.io.ByteArrayOutputStream;
 
 public class FunRISC extends FunNode implements MachNode {
     FunRISC(FunNode fun) {super(fun);}
-    // Register mask allowed on input i.  0 for no register.
-    @Override public RegMask regmap(int i) { return null; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return null; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void computeFrameAdjust(CodeGen code, int maxReg) {
+        super.computeFrameAdjust(code,maxReg);
+        if( _hasCalls )         // If non-leaf, pad to 16b
+            _frameAdjust = ((_frameAdjust+8) & -16);
+    }
+    @Override public void encoding( Encoding enc ) {
+        int sz = _frameAdjust;
+        if( sz == 0 ) return; // Skip if no frame adjust
+        if( sz >= 1L<<12 ) throw Utils.TODO();
+        enc.add4(riscv.i_type(riscv.OP_IMM, riscv.RSP, 0, riscv.RSP, -sz & 0xFFF));
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/I2F8RISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/I2F8RISC.java
index 560d1b38..5519fe5b 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/I2F8RISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/I2F8RISC.java
@@ -1,30 +1,23 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 // fcvt.d.w
+// Converts a 32-bit signed integer, in integer register rs1 into a double-precision floating-point number in floating-point register rd.
 public class I2F8RISC extends MachConcreteNode implements MachNode {
     I2F8RISC(Node i2f8) {super(i2f8);}
-
-    // Register mask allowed on input i.
+    @Override public String op() { return "cvtf"; }
     @Override public RegMask regmap(int i) { assert i==1; return riscv.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return riscv.FMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        short dst  = (short)(enc.reg(this )-riscv.F_OFFSET);
+        short src1 =         enc.reg(in(1));
+        int body = riscv.r_type(riscv.OP_FP,dst,riscv.RM.RNE.ordinal(),src1,0,0x69);
+        enc.add4(body);
     }
-
-    // General form: "i2f8 (flt)int_value"
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p("(flt)").p(code.reg(in(1)));
     }
-
-    @Override public String op() { return "i2f8"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/ImmRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/ImmRISC.java
index 02191d05..9303e566 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/ImmRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/ImmRISC.java
@@ -1,40 +1,54 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.TypeInteger;
 import java.util.BitSet;
-import java.io.ByteArrayOutputStream;
 
-public abstract class ImmRISC extends MachConcreteNode implements MachNode {
-    final int _imm;
-    ImmRISC( Node add, int imm ) {
+abstract public class ImmRISC extends MachConcreteNode implements MachNode {
+    public final int _imm12;
+    ImmRISC( Node add, int imm12, boolean pop ) {
         super(add);
-        _inputs.pop();
-        _imm = imm;
+        _imm12 = imm12;
+        // If pop, we are moving from an ideal Node to MachNode; the ideal Node
+        // inputs got copied here, but we are absorbing the immediate into the
+        // MachNode and so do not want the constant input.
+        if( pop ) _inputs.pop();
+        // if NOT pop, we are the 2nd-half of a 2-part expansion, reset the
+        // input edges to no-control
+        else { _inputs.set(0,null); _inputs.setX(1,add); }
     }
-
-    // Register mask allowed on input i.
+    ImmRISC( Node add, int imm12 ) { this(add,imm12,true); }
     @Override public RegMask regmap(int i) { return riscv.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return riscv.WMASK; }
+    @Override public boolean isClone() {
+        // Allow cloning of the 2nd half of a 2-part constant; this might
+        // trigger cloning the first part also.
+        return in(1) instanceof LUI || in(1) instanceof AUIPC;
+    }
 
     @Override public StringBuilder _print1(StringBuilder sb, BitSet visited) {
+        int imm12 = (_imm12<<20)>>20; // Sign extend 12 bits
         in(1)._print0(sb.append("( "), visited);
-        return sb.append(String.format(" %s #%d )",glabel(),_imm));
+        return sb.append(String.format(" %s #%d )",glabel(),imm12));
     }
 
     abstract int opcode();
+    abstract int func3();
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        short dst = enc.reg(this );
+        short src = enc.reg(in(1));
+        int body = riscv.i_type(opcode(), dst, func3(), src, _imm12 & 0xFFF);
+        enc.add4(body);
     }
 
     // General form: "addi  rd = rs1 + imm"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" ").p(glabel()).p(" #").p(_imm);
+        int imm12 = (_imm12<<20)>>20; // Sign extend 12 bits
+        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" ").p(glabel()).p(" #").p(imm12);
+        if( in(1) instanceof LUI lui )
+            sb.p(" // #").hex4((int)(((TypeInteger)lui._con).value()) + imm12);
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/IntRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/IntRISC.java
index e792b055..70d5c18f 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/IntRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/IntRISC.java
@@ -1,33 +1,28 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.ConstantNode;
 import com.seaofnodes.simple.node.MachNode;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeInteger;
 
-// Integer constants
+// 12-bit integer constant.  Larger constants are made up in the instruction
+// selection by adding with a LUI.
 public class IntRISC extends ConstantNode implements MachNode {
-    IntRISC(ConstantNode con) { super(con); }
+    public IntRISC(ConstantNode con) { super(con); }
     @Override public String op() { return "ldi"; }
-    // Register mask allowed on input i.  0 for no register.
     @Override public RegMask regmap(int i) { return null; }
-    // General int registers
     @Override public RegMask outregmap() { return riscv.WMASK; }
-
     @Override public boolean isClone() { return true; }
     @Override public IntRISC copy() { return new IntRISC(this); }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        short dst  = enc.reg(this);
+        int val = _con==Type.NIL ? 0 : (int)(((TypeInteger)_con).value() & 0xFFF);
+        // Explicit truncation of larger immediates; this will sign-extend on
+        // load and this is handled during instruction selection.
+        enc.add4(riscv.i_type(riscv.OP_IMM, dst, 0, riscv.ZERO, val));
     }
-
-    // Human-readable form appended to the SB.  Things like the encoding,
-    // indentation, leading address or block labels not printed here.
-    // Just something like "ld4\tR17=[R18+12] // Load array base".
-    // General form: "op\tdst=src+src"
     @Override public void asm(CodeGen code, SB sb) {
         String reg = code.reg(this);
         _con.print(sb.p(reg).p(" = #"));
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/LUI.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/LUI.java
new file mode 100644
index 00000000..75ad6496
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/LUI.java
@@ -0,0 +1,32 @@
+package com.seaofnodes.simple.node.cpus.riscv;
+
+import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.ConstantNode;
+import com.seaofnodes.simple.node.MachNode;
+import com.seaofnodes.simple.type.TypeInteger;
+
+// Load upper 20bits.
+public class LUI extends ConstantNode implements MachNode {
+    public LUI( int imm20 ) {
+        super(TypeInteger.constant(imm20));
+        assert riscv.imm20Exact((TypeInteger)_con);
+    }
+    @Override public RegMask regmap(int i) { return null; }
+    @Override public RegMask outregmap() { return riscv.WMASK; }
+    @Override public boolean isClone() { return true; }
+    @Override public LUI copy() { return new LUI((int)((TypeInteger)_con).value()); }
+    @Override public String op() { return "lui"; }
+    @Override public void encoding( Encoding enc ) {
+        long x = ((TypeInteger)_con).value();
+        int imm20 = (int)(x>>12) & 0xFFFFF;
+        short dst = enc.reg(this);
+        int lui = riscv.u_type(riscv.OP_LUI, dst, imm20);
+        enc.add4(lui);
+    }
+
+    @Override public void asm(CodeGen code, SB sb) {
+        String reg = code.reg(this);
+        sb.p(reg).p(" = #").hex4((int)(((TypeInteger)_con).value()));
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/LoadRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/LoadRISC.java
index 3fe8f44e..7b0e9138 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/LoadRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/LoadRISC.java
@@ -1,40 +1,29 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-
 
 // Load memory addressing on RISC
 // Support imm, reg(direct), or reg+off(indirect) addressing
 // Base = base - base pointer, offset is added to base
 // idx  = null
-// off  = off - offset added to base
-
+// off  = off - imm12 added to base
 public class LoadRISC extends MemOpRISC {
-    LoadRISC(LoadNode ld, Node base, Node idx, int off) {
-        super(ld, base, idx, off, 0);
-    }
-
-    @Override public RegMask regmap(int i) {
-        return riscv.RMASK;
-    }
-    // Wide mask loads both ints and floats; encoding varies.
+    public LoadRISC(LoadNode ld, Node base, int off) { super(ld, base, off, null); }
+    @Override public String op() { return "ld" +_sz; }
+    @Override public RegMask regmap(int i) { return riscv.RMASK; }
     @Override public RegMask outregmap() { return riscv.MEM_MASK; }
-
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        short dst = enc.reg(this );
+        short ptr = enc.reg(ptr());
+        int op = dst >= riscv.F_OFFSET ? riscv.OP_LOADFP  : riscv.OP_LOAD;
+        if( dst >= riscv.F_OFFSET  ) dst -= riscv.F_OFFSET;
+        enc.add4(riscv.i_type(op, dst, func3(), ptr, _off));
     }
 
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(",");
         asm_address(code,sb);
     }
-
-    @Override public String op() { return "ld" +_sz; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MemOpRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MemOpRISC.java
index bcd7924e..b8eb7644 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MemOpRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MemOpRISC.java
@@ -1,57 +1,74 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.*;
-import java.io.ByteArrayOutputStream;
-import java.lang.StringBuilder;
 import java.util.BitSet;
 
-
-public class MemOpRISC extends MemOpNode implements MachNode {
-    final int _off;             // Limit 32 bits
-    final int _imm;             // Limit 32 bits
-    final char _sz = (char)('0'+(1<<_declaredType.log_size()));
-    MemOpRISC( MemOpNode mop, Node base, Node idx, int off, int imm) {
+public abstract class MemOpRISC extends MemOpNode implements MachNode {
+    final int _off;             // Limit 12 bits
+    final char _sz;
+    MemOpRISC(MemOpNode mop, Node base, int off, Node val) {
         super(mop,mop);
-        assert base._type instanceof TypeMemPtr && !(base instanceof AddNode);
-        assert ptr() == base;
-        _inputs.setX(3,idx);
+        assert base._type instanceof TypeMemPtr;
+        _inputs.setX(2, base ); // Base can be an Add, is no longer raw object base
+        _inputs.setX(3, null);  // Never an index
+        _inputs.setX(4, val );
         _off = off;
-        _imm = imm;
-    }
-    // Store-based flavors have a value edge
-    MemOpRISC( MemOpNode mop, Node base, Node idx, int off, int imm, Node val ) {
-        this(mop,base,idx,off,imm);
-        _inputs.setX(4,val);
+        _sz = (char)('0'+(1<<_declaredType.log_size()));
     }
 
-    Node idx() { return in(3); }
-    Node val() { return in(4); } // Only for stores, including op-to-memory
+    @Override public String label() { return op(); }
+    Node val() { return in(4); } // Only for stores
 
-    @Override public  StringBuilder _printMach(StringBuilder sb, BitSet visited) { return sb.append(".").append(_name); }
+    @Override public StringBuilder _printMach(StringBuilder sb, BitSet visited) { return sb.append(".").append(_name); }
 
-    @Override public String label() { return op(); }
     @Override public Type compute() { throw Utils.TODO(); }
     @Override public Node idealize() { throw Utils.TODO(); }
 
+    // func3 is based on load/store size and extend
+    int func3() {
+        int func3 = -1;
+        // no unsigned flavour for store, so both signed and unsigned trigger the same
+        if(this instanceof StoreRISC) {
+            if( _declaredType == TypeInteger. I8 || _declaredType == TypeInteger.U8  || _declaredType == TypeInteger.BOOL) func3=0; //   SB
+            if( _declaredType == TypeInteger.I16 || _declaredType == TypeInteger.U16 ) func3=1; // SH
+            if( _declaredType == TypeInteger.I32 || _declaredType == TypeInteger.U32 || _declaredType instanceof TypeMemPtr) func3=2; //  SW
+            if( _declaredType == TypeInteger.BOT ) func3=3; //   SD
+            if( func3 == -1 ) throw Utils.TODO();
+            return func3;
+        }
+        if( _declaredType == TypeInteger. I8 ) func3=0; // LB
+        if( _declaredType == TypeInteger.I16 ) func3=1; // LH
+        if( _declaredType == TypeInteger.I32 ) func3=2; // LW
+        if( _declaredType == TypeInteger.BOT ) func3=3; // LD
+        if( _declaredType == TypeInteger. U8 ) func3=4; // LBU
+        if( _declaredType == TypeInteger.BOOL) func3=4; // LBU
+        if( _declaredType == TypeInteger.U16 ) func3=5; // LHU
+        if( _declaredType == TypeInteger.U32 ) func3=6; // LWU
+
+        // float
+        if(_declaredType == TypeFloat.F32) func3 = 2; // fLW   fSW
+        if(_declaredType == TypeFloat.F64) func3 = 3; // fLD   fSD
+        if( _declaredType instanceof TypeMemPtr ) func3=3; // 8 byte pointers
+        if( func3 == -1 ) throw Utils.TODO();
+        return func3;
+    }
 
     // Register mask allowed on input i.
     @Override public RegMask regmap(int i) {
+        // 0 - ctrl
+        // 1 - memory
+        if( i==2 ) return riscv.RMASK;    // base
+        // 2 - index
+        if( i==4 ) return riscv.MEM_MASK; // value
         throw Utils.TODO();
     }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { throw Utils.TODO(); }
-
-    @Override public int encoding(ByteArrayOutputStream bytes) { throw Utils.TODO(); }
-
 
     SB asm_address(CodeGen code, SB sb) {
         sb.p("[").p(code.reg(ptr())).p("+");
-        if( idx() != null ) sb.p(code.reg(idx()));
-        else sb.p(_off);
-        return sb.p("]");
+        return sb.p(_off).p("]");
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MulFRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MulFRISC.java
index 8a066ab1..c9917b4f 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MulFRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MulFRISC.java
@@ -1,30 +1,17 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import java.io.ByteArrayOutputStream;
 
-public class MulFRISC extends MachConcreteNode implements MachNode{
+// fmul.d
+public class MulFRISC extends MachConcreteNode implements MachNode {
     MulFRISC(Node mulf) {super(mulf);}
-
-    // Register mask allowed on input i.
+    @Override public String op() { return "mulf"; }
     @Override public RegMask regmap(int i) { assert i==1 || i==2; return riscv.FMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return riscv.FMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // Default on double precision for now(64 bits)
-    // General form: "fmul.d  rd = src1 * src2
+    @Override public void encoding( Encoding enc ) { riscv.rf_type(enc,this,riscv.RM.RNE,9); }
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" * ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "mulf"; }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MulRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MulRISC.java
index 0e2d35a3..a7961627 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MulRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/MulRISC.java
@@ -1,32 +1,17 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-
 
 // mulh signed multiply instruction(no-imm form)
 public class MulRISC extends MachConcreteNode implements MachNode{
-    MulRISC(Node mul) {super(mul);}
-
-    // Register mask allowed on input i.
+    public MulRISC(Node mul) {super(mul);}
+    @Override public String op() { return "mul"; }
     @Override public RegMask regmap(int i) { assert i==1 || i==2; return riscv.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return riscv.WMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form: "rd = rs1 * rs2"
+    @Override public void encoding( Encoding enc ) { riscv.r_type(enc,this,0,1);  }
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" * ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "mul"; }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NegRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NegRISC.java
new file mode 100644
index 00000000..77f4a497
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NegRISC.java
@@ -0,0 +1,20 @@
+package com.seaofnodes.simple.node.cpus.riscv;
+
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
+
+public class NegRISC extends MachConcreteNode implements MachNode {
+    public NegRISC( Node neg ) { super(neg); }
+    @Override public String op() { return "neg"; }
+    @Override public RegMask regmap(int i) { assert i==1; return riscv.RMASK; }
+    @Override public RegMask outregmap() { return riscv.WMASK; }
+    @Override public void encoding( Encoding enc ) {
+        short dst = enc.reg(this );
+        short src = enc.reg(in(1));
+        riscv.r_type(riscv.OP,dst,0,0,src,0x20);
+    }
+    @Override public void asm(CodeGen code, SB sb) {
+        sb.p(code.reg(this)).p(" = -").p(code.reg(in(1)));
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NewRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NewRISC.java
index 53ad0af2..e395a811 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NewRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NewRISC.java
@@ -1,29 +1,46 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.print.ASMPrinter;
 
-public class NewRISC extends NewNode implements MachNode {
+public class NewRISC extends NewNode implements MachNode, RIPRelSize {
     // A pre-zeroed chunk of memory.
     NewRISC( NewNode nnn ) { super(nnn); }
-    // Size and pointer result in standard calling convention; null for all the
-    // memory aliases edges
-    @Override public RegMask    regmap(int i) { return i == 1 ? riscv.A0_MASK : null; }
-    @Override public RegMask outregmap(int i) { return i == 1 ? riscv.A0_MASK : null; }
-    @Override public RegMask outregmap() { return null; }
+    @Override public void encoding( Encoding enc ) {
+        // Generic external encoding; 2 ops.
+        enc.external(this,"calloc");
+        // A1 is a caller-save, allowed to crush building external address
+        // auipc
+        enc.add4(riscv.i_type(riscv.OP_IMM  , _arg2Reg , 0, riscv.ZERO, 1));
+        enc.add4(riscv.u_type(riscv.OP_AUIPC, riscv.A2 , 0));
+        enc.add4(riscv.i_type(riscv.OP_JALR , riscv.RPC, 0, riscv.A2, 0));
+    }
+
+    // Patch is for running "new" in a JIT.
+    // Delta is from opcode start
+    @Override public byte encSize(int delta) { return 4*3; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    // Patch is for running "new" in a JIT.
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        // Negative patches are JIT emulator targets.
+        if( opStart+delta < 0 ) {
+            delta -= 4;         // Offset from the AUIPC start
+            int imm20 = delta>>12;
+            if( ((delta>>11)&1)==1 ) imm20++; // Correct accidental sign extension
+            int imm12 = delta&0xFFF;
+            enc.patch4(opStart+4,riscv.u_type(riscv.OP_AUIPC, riscv.A2 , imm20));
+            enc.patch4(opStart+8,riscv.i_type(riscv.OP_JALR , riscv.RPC, 0, riscv.A2, imm12));
+        } else
+            throw Utils.TODO();
     }
 
-    // General form: "alloc #bytes"
+    // General form: "alloc #bytes  PC"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(size()));
+        sb.p("ldi   a1=#1\n");
+        sb.p("auipc a2=#calloc\n");
+        sb.p("call  a2+#calloc, a0");
     }
-
-    @Override public String op() { return "alloc"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NotRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NotRISC.java
index 6d30cd1c..9cbd5025 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NotRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/NotRISC.java
@@ -1,25 +1,20 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.LRG;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.MachConcreteNode;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.node.MachNode;
+import com.seaofnodes.simple.node.NotNode;
 
 public class NotRISC extends MachConcreteNode implements MachNode {
-    NotRISC(NotNode not) {super(not);}
+    public NotRISC(NotNode not) { super(not); }
+    @Override public String op() { return "not"; }
     @Override public RegMask regmap(int i) { return riscv.RMASK; }
-    @Override public RegMask outregmap() { return riscv.RMASK;  }
-
-    @Override public int twoAddress( ) { return 0; }
-
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public RegMask outregmap()   { return riscv.WMASK; }
+    @Override public void encoding( Encoding enc ) {
+        short dst = enc.reg(this );
+        short src = enc.reg(in(1));
+        enc.add4(riscv.i_type(riscv.OP_IMM, dst, 2, src, 1));
     }
-
     @Override public void asm(CodeGen code, SB sb) { sb.p(code.reg(this)); }
-    @Override public String op() { return "not"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/OrIRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/OrIRISC.java
index f41d7162..f6a888d9 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/OrIRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/OrIRISC.java
@@ -4,8 +4,9 @@ import com.seaofnodes.simple.Utils;
 import com.seaofnodes.simple.node.Node;
 
 public class OrIRISC extends ImmRISC {
-    OrIRISC( Node and, int imm) { super(and,imm); }
-    @Override int opcode() { throw Utils.TODO(); }
+    public OrIRISC( Node and, int imm) { super(and,imm); }
+    @Override int opcode() {  return riscv.OP_IMM; }
+    @Override int func3() {  return 6; }
     @Override public String glabel() { return "|"; }
     @Override public String op() { return "ori"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/OrRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/OrRISC.java
index 7f808f90..103d4c7d 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/OrRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/OrRISC.java
@@ -1,39 +1,16 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.MachConcreteNode;
-import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.node.Node;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
 
 public class OrRISC extends MachConcreteNode implements MachNode {
-    OrRISC(Node or) {
-        super(or);
-    }
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        assert i==1 || i==2;
-        return riscv.RMASK;
-    }
-
-    // Register mask allowed as a result.  0 for no register.
+    public OrRISC(Node or) { super(or); }
+    @Override public String op() { return "or"; }
+    @Override public RegMask regmap(int i) { return riscv.RMASK; }
     @Override public RegMask outregmap() { return riscv.WMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form:  # rd = rs1 | rs2
+    @Override public void encoding( Encoding enc ) { riscv.r_type(enc,this,6,0);  }
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" | ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "or"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/ParmRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/ParmRISC.java
index 75674f37..0f8db4e5 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/ParmRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/ParmRISC.java
@@ -1,26 +1,17 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.node.ParmNode;
-import java.io.ByteArrayOutputStream;
 
 public class ParmRISC extends ParmNode implements MachNode {
     final RegMask _rmask;
     ParmRISC(ParmNode parm) {
         super(parm);
-        // Assume int
-        _rmask = riscv.callInMask(fun().sig(),_idx);
+        _rmask = riscv.callInMask(fun().sig(),_idx,0);
     }
-
-    // Register mask allowed on input i.  0 for no register.
-    @Override public RegMask regmap(int i) { return _rmask; }
-    // Register mask allowed as a result.  Calling convention register
+    @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return _rmask; }
-
-    // Encoding is appended into the byte array.  Returns size
-    @Override public int encoding(ByteArrayOutputStream bytes) { return 0; }
+    @Override public void encoding( Encoding enc ) { }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/ProjRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/ProjRISC.java
index 42d5dc9b..2f9ac469 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/ProjRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/ProjRISC.java
@@ -1,25 +1,15 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.node.ProjNode;
-import java.io.ByteArrayOutputStream;
 
 public class ProjRISC extends ProjNode implements MachNode {
     ProjRISC(ProjNode p) { super(p); }
-
-    // Register mask allowed on input i.  0 for no register.
     @Override public RegMask regmap(int i) { return null; }
-    // Register mask allowed as a result.
     @Override public RegMask outregmap() {
         return ((MachNode)in(0)).outregmap(_idx);
     }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
+    @Override public void encoding( Encoding enc ) { }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/RetRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/RetRISC.java
index c9fa7fac..8a8186cd 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/RetRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/RetRISC.java
@@ -2,47 +2,20 @@ package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.*;
 import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.node.FunNode;
 import com.seaofnodes.simple.node.ReturnNode;
 import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.type.TypeFloat;
 
-import java.io.ByteArrayOutputStream;
-
-public class RetRISC extends ReturnNode implements MachNode{
-    RetRISC(ReturnNode ret, FunNode fun) { super(ret, fun); fun.setRet(this); }
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) { return riscv.retMask(_fun.sig(),i); }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return null; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+public class RetRISC extends ReturnNode implements MachNode {
+    public RetRISC(ReturnNode ret, FunNode fun) { super(ret, fun); fun.setRet(this); }
+    @Override public void encoding( Encoding enc ) {
+        int sz = fun()._frameAdjust;
+        if( sz >= 1L<<12 ) throw Utils.TODO();
+        if( sz != 0 )
+            enc.add4(riscv.i_type(riscv.OP_IMM, riscv.RSP, 0, riscv.RSP, sz & 0xFFF));
+        short rpc = enc.reg(rpc());
+        enc.add4(riscv.i_type(riscv.OP_JALR, riscv.ZERO, 0, rpc, 0));
     }
-
-    @Override public void asm(CodeGen code, SB sb) {
-        // Post code-gen, just print the "ret"
-        if( code._phase.ordinal() <= CodeGen.Phase.RegAlloc.ordinal() )
-            // Prints return reg (either A0 or FA0), RPC (always R1) and then
-            // the callee-save registers.
-            for( int i=2; i<nIns(); i++ )
-                sb.p(code.reg(in(i))).p("  ");
-
-        // Post-allocation, if we did not get the expected return register, print what we got
-        else if( code._regAlloc.regnum(in(3)) != riscv.RPC )
-            sb.p("[").p(code.reg(in(3))).p("]");
-    }
-
-    // Correct Nodes outside the normal edges
-    @Override public void postSelect() {
-        FunNode fun = (FunNode)rpc().in(0);
-        _fun = fun;
-        fun.setRet(this);
-    }
-
-    @Override public String op() { return "ret"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SetFRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SetFRISC.java
index 3f9fc192..9ee19e42 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SetFRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SetFRISC.java
@@ -1,15 +1,14 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.BoolNode;
 import com.seaofnodes.simple.node.MachConcreteNode;
 import com.seaofnodes.simple.node.MachNode;
-import java.io.ByteArrayOutputStream;
 
-// corresponds to slt,sltu,slti,sltiu, seqz
+// corresponds to feq.d = equal
+//                fle.d = less than or equal
+//                flt.d = less than
 public class SetFRISC extends MachConcreteNode implements MachNode {
     final String _bop;          // One of <,<=,==
     SetFRISC( BoolNode bool ) {
@@ -17,17 +16,18 @@ public class SetFRISC extends MachConcreteNode implements MachNode {
         assert bool.isFloat();
         _bop = bool.op();
     }
+    @Override public String op() { return "set"+_bop; }
     @Override public RegMask regmap(int i) { return riscv.FMASK; }
     @Override public RegMask outregmap() { return riscv.WMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        short dst  =         enc.reg(this );
+        short src1 = (short)(enc.reg(in(1))-riscv.F_OFFSET);
+        short src2 = (short)(enc.reg(in(2))-riscv.F_OFFSET);
+        int body = riscv.r_type(riscv.OP_FP,dst,riscv.fsetop(_bop),src1,src2,0b1010001/*FCMP*/);
+        enc.add4(body);
     }
 
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(in(1))).p(" ").p(_bop).p(" ").p(code.reg(in(2)));
+        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" ").p(_bop).p(" ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "set"+_bop; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SetIRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SetIRISC.java
index 3c0f76ae..f270bf12 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SetIRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SetIRISC.java
@@ -1,17 +1,17 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.node.BoolNode;
+import com.seaofnodes.simple.node.Node;
 
-// corresponds to slt,sltu,slti,sltiu, seqz
+// corresponds to slti,sltiu
 public class SetIRISC extends ImmRISC {
-    final String _bop;          // One of <,<=,==
-    SetIRISC( BoolNode bool, int imm ) {
-        super(bool,imm);
-        assert !bool.isFloat();
-        _bop = bool.op();
+    final boolean _unsigned;    // slti vs sltiu
+    public SetIRISC( Node src, int imm12, boolean unsigned ) {
+        super(src,imm12);
+        _unsigned = unsigned;
     }
-    @Override int opcode() { throw Utils.TODO(); }
-    @Override public String glabel() { return _bop; }
-    @Override public String op() { return "set"+_bop; }
+    @Override public String op() { return "slt" + (_unsigned ? "u":"") + "i"; }
+    @Override public String glabel() { return  "<"+ (_unsigned ? "u":""); }
+    @Override int opcode() { return 0b0010011; }
+    @Override int func3() { return _unsigned ? 0b011 : 0b010; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SetRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SetRISC.java
index fb7650c7..8d4a2f71 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SetRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SetRISC.java
@@ -1,33 +1,20 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.BoolNode;
-import com.seaofnodes.simple.node.MachConcreteNode;
-import com.seaofnodes.simple.node.MachNode;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
 
-// corresponds to slt,sltu,slti,sltiu, seqz
+// corresponds to slt sltu
 public class SetRISC extends MachConcreteNode implements MachNode {
-    final String _bop;          // One of <,<=,==
-    SetRISC( BoolNode bool ) {
-        super(bool);
-        assert !bool.isFloat();
-        _bop = bool.op();
-    }
-    @Override public RegMask regmap(int i) { throw Utils.TODO(); }
+    final boolean _unsigned;
+    public SetRISC( Node cmp, boolean unsigned ) { super(cmp); _unsigned=unsigned; }
+    @Override public String op() { return "slt" + (_unsigned ? "u":""); }
+    @Override public RegMask regmap(int i) { return riscv.RMASK; }
     @Override public RegMask outregmap() { return riscv.WMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        riscv.r_type(enc,this,_unsigned ? 0b011 : 0b010,0);
     }
-
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(in(1))).p(" ").p(_bop).p(" ").p(code.reg(in(2)));
+        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" < ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "set"+_bop; }
-}
+}
\ No newline at end of file
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SllIRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SllIRISC.java
index b5202908..4edecc04 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SllIRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SllIRISC.java
@@ -4,8 +4,9 @@ import com.seaofnodes.simple.Utils;
 import com.seaofnodes.simple.node.Node;
 
 public class SllIRISC extends ImmRISC {
-    SllIRISC( Node and, int imm) { super(and,imm); }
-    @Override int opcode() { throw Utils.TODO(); }
+    public SllIRISC( Node and, int imm) { super(and,imm); }
+    @Override int opcode() {  return riscv.OP_IMM; }
+    @Override int func3() {  return 1; }
     @Override public String glabel() { return "<<"; }
     @Override public String op() { return "slli"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SllRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SllRISC.java
index 447f604a..87e6693e 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SllRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SllRISC.java
@@ -1,37 +1,17 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
 
-public class SllRISC extends MachConcreteNode implements MachNode{
-    SllRISC(Node sll) {super(sll);}
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        //assert i==1;
-        return riscv.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
+// Shift left logical
+public class SllRISC extends MachConcreteNode implements MachNode {
+    public SllRISC(Node sll) { super(sll); }
+    @Override public String op() { return "shl"; }
+    @Override public RegMask regmap(int i) { return riscv.RMASK; }
     @Override public RegMask outregmap() { return riscv.WMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form: "sll rd, rs1, rs2"
+    @Override public void encoding( Encoding enc ) { riscv.r_type(enc,this,1,0);  }
     @Override public void asm(CodeGen code, SB sb) {
-
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" << ").p(code.reg(in(2)));
-
     }
-
-    @Override public String op() { return "sll"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SplitRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SplitRISC.java
index b5076ba0..569fa2e0 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SplitRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SplitRISC.java
@@ -1,21 +1,66 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
+import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.FunNode;
 import com.seaofnodes.simple.node.Node;
 import com.seaofnodes.simple.node.SplitNode;
-import java.io.ByteArrayOutputStream;
 
 public class SplitRISC extends SplitNode {
     SplitRISC( String kind, byte round ) { super(kind,round, new Node[2]); }
-
-    // Register mask allowed on input i.
     @Override public RegMask regmap(int i) { return riscv.SPLIT_MASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return riscv.SPLIT_MASK; }
+    @Override public void encoding( Encoding enc ) {
+        short dst = enc.reg(this );
+        short src = enc.reg(in(1));
+
+        // Flag for being either XMM or stack
+        boolean dstX = dst >= riscv.F_OFFSET;
+        boolean srcX = src >= riscv.F_OFFSET;
+
+        if( dst >= riscv.MAX_REG ) {
+            // Store to SP
+            if( src >= riscv.MAX_REG ) {
+                throw Utils.TODO(); // Very rare stack-stack move
+            }
+            int off = enc._fun.computeStackOffset(enc._code,dst);
+            int op = srcX ? riscv.OP_STOREFP : riscv.OP_STORE;
+            if( srcX ) src -= riscv.F_OFFSET;
+            enc.add4(riscv.s_type(op, 0b011, riscv.RSP, src, off));
+            return;
+        }
+        if( src >= riscv.MAX_REG ) {
+            // Load from SP
+            int off = enc._fun.computeStackOffset(enc._code,src);
+            int op = dstX ? riscv.OP_LOADFP : riscv.OP_LOAD;
+            if( dstX ) dst -= riscv.F_OFFSET;
+            enc.add4(riscv.i_type(op, dst, 0b011, riscv.RSP, off));
+            return;
+        }
+        // pick opcode based on regs
+        if( !dstX && !srcX ) {
+            // GPR->GPR
+            enc.add4(riscv.r_type(riscv.OP,dst,0,src,riscv.ZERO,0));
+        } else if( dstX && srcX ) {
+            // FPR->FPR
+            src -= riscv.F_OFFSET;
+            dst -= riscv.F_OFFSET;
+            enc.add4(riscv.r_type(riscv.OP_FP, dst, 0b000, src, src, 0b0010101)); // dst = FMIN(src,src)
+        } else if(!srcX && dstX) {
+            //GPR->FPR
+            // fmv.d.x
+            enc.add4(riscv.r_type(riscv.OP_FP, dst - riscv.F_OFFSET, 0, src, 0, 0b1111001));
+        } else if(srcX && !dstX) {
+            //FPR->GPR
+            //fmv.x.d
+            enc.add4(riscv.r_type(riscv.OP_FP, dst, 0, src - riscv.F_OFFSET, 0, 0b1110001));
+        }
+    }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    // General form: "mov  dst = src"
+    @Override public void asm(CodeGen code, SB sb) {
+        FunNode fun = code._encoding==null ? null : code._encoding._fun;
+        sb.p(code.reg(this,fun)).p(" = ").p(code.reg(in(1),fun));
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SraIRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SraIRISC.java
index d5ab5e08..26404e95 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SraIRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SraIRISC.java
@@ -4,8 +4,9 @@ import com.seaofnodes.simple.Utils;
 import com.seaofnodes.simple.node.Node;
 
 public class SraIRISC extends ImmRISC {
-    SraIRISC( Node and, int imm) { super(and,imm); }
-    @Override int opcode() { throw Utils.TODO(); }
+    public SraIRISC( Node and, int imm) { super(and,imm); }
+    @Override int opcode() {  return riscv.OP_IMM; }
+    @Override int func3() {  return 5;}
     @Override public String glabel() { return ">>"; }
     @Override public String op() { return "srai"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SraRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SraRISC.java
index 0726e292..1e930e72 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SraRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SraRISC.java
@@ -1,38 +1,17 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.MachConcreteNode;
-import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.node.Node;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
 
 // Right Shift Arithmetic
 public class SraRISC extends MachConcreteNode implements MachNode {
-
-    SraRISC(Node sra) {super(sra);}
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        // assert i==1;
-        return riscv.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
+    public SraRISC(Node sra) { super(sra); }
+    @Override public String op() { return "sar"; }
+    @Override public RegMask regmap(int i) { return riscv.RMASK; }
     @Override public RegMask outregmap() { return riscv.WMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form: "sra rd, rs1, rs2"
+    @Override public void encoding( Encoding enc ) { riscv.r_type(enc,this,0b101,0b00100000);  }
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" >> ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "sra"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SrlIRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SrlIRISC.java
index a4eb99bc..ed697678 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SrlIRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SrlIRISC.java
@@ -4,8 +4,9 @@ import com.seaofnodes.simple.Utils;
 import com.seaofnodes.simple.node.Node;
 
 public class SrlIRISC extends ImmRISC {
-    SrlIRISC( Node and, int imm) { super(and,imm); }
-    @Override int opcode() { throw Utils.TODO(); }
+    public SrlIRISC( Node and, int imm, boolean pop) { super(and,imm,pop); }
+    @Override int opcode() {  return riscv.OP_IMM; }
+    @Override int func3() {  return 5; }
     @Override public String glabel() { return ">>>"; }
     @Override public String op() { return "srli"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SrlRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SrlRISC.java
index d1435540..47712585 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SrlRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SrlRISC.java
@@ -1,38 +1,17 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
-import java.lang.StringBuilder;
 
 // Right Shift Logical
 public class SrlRISC extends MachConcreteNode implements MachNode {
-    SrlRISC(Node srli) {super(srli);}
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        // assert i==1;
-        return riscv.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
+    public SrlRISC(Node srli) { super(srli); }
+    @Override public String op() { return "shr"; }
+    @Override public RegMask regmap(int i) { return riscv.RMASK; }
     @Override public RegMask outregmap() { return riscv.WMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form: "srl rd, rs1, rs2"
+    @Override public void encoding( Encoding enc ) { riscv.r_type(enc,this,7,0);  }
     @Override public void asm(CodeGen code, SB sb) {
-
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" >>> ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "srl"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/StoreRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/StoreRISC.java
index c57cf11d..7305c4d9 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/StoreRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/StoreRISC.java
@@ -2,14 +2,9 @@ package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.MachConcreteNode;
-import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.node.Node;
-import com.seaofnodes.simple.node.StoreNode;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
+import com.seaofnodes.simple.node.*;
 
 // Store memory addressing on ARM
 // Support imm, reg(direct), or reg+off(indirect) addressing
@@ -24,33 +19,29 @@ import java.util.BitSet;
 
 // sw rs2,offset(rs1)
 public class StoreRISC extends MemOpRISC {
-    StoreRISC( StoreNode st, Node base, Node idx, int off, int imm, Node val ) {
-        super(st, base, idx, off, imm, val);
-    }
-
-    // Wider mask to store both GPRs and FPRs
+    StoreRISC( StoreNode st, Node base, int off, Node val ) { super(st, base, off, val); }
+    @Override public String op() { return "st"+_sz; }
     @Override public RegMask regmap(int i) {
-        if( i==1 ) return riscv.MEM_MASK;
-        if( i==2 ) return riscv.RMASK;
-        if( i==3 ) return riscv.RMASK;
-        if( i==4 ) return riscv.RMASK;
-        throw Utils.TODO();
+        // 0 - ctrl
+        if( i==1 ) return null; // mem
+        if( i==2 ) return riscv.RMASK; // ptr
+        // 2 - index
+        if( i==4 ) return riscv.MEM_MASK; // Wide mask to store GPR and FPR
+        return null; // Anti-dependence
     }
-
-
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return null; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        short val = enc.reg(val());
+        short ptr = enc.reg(ptr());
+        int op = val >= riscv.F_OFFSET ? riscv.OP_STOREFP : riscv.OP_STORE;
+        if( val >= riscv.F_OFFSET  ) val -= riscv.F_OFFSET;
+        enc.add4(riscv.s_type(op, func3()&7, ptr, val == -1 ? riscv.ZERO : val, _off));
     }
 
     @Override public void asm(CodeGen code, SB sb) {
         asm_address(code,sb).p(",");
-        if( val()==null ) sb.p("#").p(_imm);
+        if( val()==null ) sb.p("#").p("0");
         else sb.p(code.reg(val()));
     }
-
-    @Override public String op() { return "st"+_sz; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SubFRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SubFRISC.java
index e6fe3012..1e1b43c7 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SubFRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SubFRISC.java
@@ -1,30 +1,17 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
-public class SubFRISC extends MachConcreteNode implements MachNode{
+// fsub.d
+public class SubFRISC extends MachConcreteNode implements MachNode {
     SubFRISC(Node subf) {super(subf);}
-
-    // Register mask allowed on input i.
+    @Override public String op() { return "subf"; }
     @Override public RegMask regmap(int i) { assert i==1 || i==2; return riscv.FMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return riscv.FMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // Default on double precision for now(64 bits)
-    // General form: "fsub.d  rd = src1 - src2
+    @Override public void encoding( Encoding enc ) { riscv.rf_type(enc,this,riscv.RM.RNE,5); }
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" + ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "subf"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SubRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SubRISC.java
index c37aea98..7ab4f904 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SubRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/SubRISC.java
@@ -1,29 +1,16 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class SubRISC extends MachConcreteNode implements MachNode {
-    SubRISC( Node sub ) { super(sub); }
-
-    // Register mask allowed on input i.
+    public SubRISC( Node sub ) { super(sub); }
+    @Override public String op() { return "sub"; }
     @Override public RegMask regmap(int i) { assert i==1 || i==2; return riscv.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return riscv.WMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form: "sub  # rd = rs1 - rs2"
+    @Override public void encoding( Encoding enc ) { riscv.r_type(enc,this,0,0x20);  }
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" - ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "sub"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TFPRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TFPRISC.java
index 23fb6a74..17613009 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TFPRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TFPRISC.java
@@ -1,39 +1,55 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.ConstantNode;
 import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeFunPtr;
-import java.io.ByteArrayOutputStream;
 
-public class TFPRISC extends ConstantNode implements MachNode{
-    TFPRISC(ConstantNode con) {super(con);}
-    @Override public String op() { return _con == Type.NIL ? "xor" : "ldx"; }
-    // Register mask allowed on input i.  0 for no register.
+public class TFPRISC extends ConstantNode implements MachNode, RIPRelSize {
+    TFPRISC(ConstantNode con) { super(con); }
+    @Override public String op() { return "ldx"; }
     @Override public RegMask regmap(int i) { return null; }
-    // General int registers
     @Override public RegMask outregmap() { return riscv.WMASK; }
-
     @Override public boolean isClone() { return true; }
     @Override public TFPRISC copy() { return new TFPRISC(this); }
+    @Override public void encoding( Encoding enc ) {
+        enc.relo(this);
+        // TODO: 1 op encoding, plus a TODO if it does not fit
+        short dst = enc.reg(this);
+        TypeFunPtr tfp = (TypeFunPtr)_con;
+        // auipc  t0,0
+        int auipc = riscv.u_type(riscv.OP_AUIPC, dst, 0);
+        // addi   t1,t0 + #0
+        int addi = riscv.i_type(riscv.OP_IMM, dst, 0, dst, 0);
+        enc.add4(auipc);
+        enc.add4(addi);
+    }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
+    @Override public byte encSize(int delta) {
+        if( -(1L<<11) <= delta && delta < (1L<<11) ) return 4;
         throw Utils.TODO();
     }
 
-    // Human-readable form appended to the SB.  Things like the encoding,
-    // indentation, leading address or block labels not printed here.
-    // Just something like "ld4\tR17=[R18+12] // Load array base".
-    // General form: "op\tdst=src+src"
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        short rpc = enc.reg(this);
+        if( opLen==8 ) {
+            // AUIPC (upper 20 bits)
+            // opstart of add
+            int next = opStart + opLen;
+            enc.patch4(opStart,riscv.u_type(riscv.OP_AUIPC, rpc, delta));
+            // addi(low 12 bits)
+            enc.patch4(next,riscv.i_type(riscv.OP_IMM, rpc, 0, rpc, delta & 0xFFF));
+            // addi
+        } else {
+             // should not happen as one instruction is 4 byte, and TFP arm encodes 2.
+            throw Utils.TODO();
+        }
+    }
+
     @Override public void asm(CodeGen code, SB sb) {
-        String reg = code.reg(this);
-        if( _con == Type.NIL )
-            sb.p(reg).p(",").p(reg);
-        else
-            _con.print(sb.p(reg).p(" #"));
+        _con.print(sb.p(code.reg(this)).p(" #"));
     }
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/UJmpRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/UJmpRISC.java
new file mode 100644
index 00000000..6473d81c
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/UJmpRISC.java
@@ -0,0 +1,46 @@
+package com.seaofnodes.simple.node.cpus.riscv;
+
+import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.Type;
+import java.util.BitSet;
+
+// unconditional jump
+public class UJmpRISC extends CFGNode implements MachNode, RIPRelSize {
+    @Override public String op() { return "jmp"; }
+    @Override public String label() { return op(); }
+    @Override public StringBuilder _print1( StringBuilder sb, BitSet visited ) { return sb.append("jmp "); }
+    @Override public RegMask regmap(int i) {return null; }
+    @Override public RegMask outregmap() { return null; }
+    @Override public Type compute() { throw Utils.TODO(); }
+    @Override public Node idealize() { throw Utils.TODO(); }
+    @Override public void encoding( Encoding enc ) {
+        // Short form +/-4K:  beq r0,r0,imm12
+        // Long form:  auipc rX,imm20/32; jal r0,[rX+imm12/32]
+        enc.jump(this,uctrl());
+        enc.add4(riscv.j_type(riscv.OP_JAL, 0, 0));
+    }
+
+    // Delta is from opcode start
+    @Override public byte encSize(int delta) {
+        if( -(1L<<20) <= delta && delta < (1L<<20) ) return 4;
+        // 2 word encoding needs a tmp register, must teach RA
+        throw Utils.TODO();
+    }
+
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        if( opLen==4 ) {
+            enc.patch4(opStart,riscv.j_type(riscv.OP_JAL, 0, delta));
+        } else {
+            throw Utils.TODO();
+        }
+    }
+
+    @Override public void asm(CodeGen code, SB sb) {
+        CFGNode target = uctrl();
+        //assert target.nOuts() > 1; // Should optimize jmp to empty targets
+        sb.p(label(target));
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/XorIRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/XorIRISC.java
index a2e32f06..61f25be2 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/XorIRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/XorIRISC.java
@@ -4,8 +4,9 @@ import com.seaofnodes.simple.Utils;
 import com.seaofnodes.simple.node.Node;
 
 public class XorIRISC extends ImmRISC {
-    XorIRISC( Node and, int imm) { super(and,imm); }
-    @Override int opcode() { throw Utils.TODO(); }
+    public XorIRISC( Node and, int imm) { super(and,imm); }
+    @Override int opcode() {  return riscv.OP_IMM; }
+    @Override int func3() {  return 4; }
     @Override public String glabel() { return "^"; }
     @Override public String op() { return "xori"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/XorRISC.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/XorRISC.java
index f4ecb430..725d2b78 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/XorRISC.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/XorRISC.java
@@ -1,41 +1,16 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.MachConcreteNode;
-import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.node.Node;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
 
 public class XorRISC extends MachConcreteNode implements MachNode {
-
-    XorRISC(Node or) {
-        super(or);
-    }
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        assert i==1 || i==2;
-        return riscv.RMASK;
-    }
-
-    // Register mask allowed as a result.  0 for no register.
+    public XorRISC(Node or) { super(or); }
+    @Override public String op() { return "xor"; }
+    @Override public RegMask regmap(int i) { return riscv.RMASK; }
     @Override public RegMask outregmap() { return riscv.WMASK; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form:  # # rd = rs1 ^ rs2
+    @Override public void encoding( Encoding enc ) { riscv.r_type(enc,this,4,0);  }
     @Override public void asm(CodeGen code, SB sb) {
-
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" ^ ").p(code.reg(in(2)));
-
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/riscv.java b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/riscv.java
index 83706cbf..54c6b828 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/riscv/riscv.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/riscv/riscv.java
@@ -1,49 +1,63 @@
 package com.seaofnodes.simple.node.cpus.riscv;
 
 import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.LRG;
-import com.seaofnodes.simple.codegen.Machine;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.*;
 
 public class riscv extends Machine {
+
+    public riscv(CodeGen code) {
+        if( !"SystemV".equals(code._callingConv) )
+            throw new IllegalArgumentException("Unknown calling convention "+code._callingConv);
+    }
+
     @Override public String name() {return "riscv";}
+    //@Override public int maxReg() { return MAX_REG; }
 
     // Using ABI names instead of register names
-    static final int             RPC=  1,  SP =  2,  GP =  3,  TP =  4,  T0 =  5,  T1 =  6,  T2 =  7;
-    static final int S0   =  8,  S1 =  9,  A0 = 10,  A1 = 11,  A2 = 12,  A3 = 13,  A4 = 14,  A5 = 15;
-    static final int A6   = 16,  A7 = 17,  S2 = 18,  S3 = 19,  S4 = 20,  S5 = 21,  S6 = 22,  S7 = 23;
-    static final int S8   = 24,  S9 = 25,  S10 = 26, S11 = 27, T3 = 28,  T4 = 29,  T5 = 30,  T6 = 31;
+    public static int ZERO =  0,  RPC=  1,  RSP=  2,  S12=  3,  S13=  4,  T0 =  5,  T1 =  6,  T2 =  7;
+    public static int S0   =  8,  S1 =  9,  A0 = 10,  A1 = 11,  A2 = 12,  A3 = 13,  A4 = 14,  A5 = 15;
+    public static int A6   = 16,  A7 = 17,  S2 = 18,  S3 = 19,  S4 = 20,  S5 = 21,  S6 = 22,  S7 = 23;
+    public static int S8   = 24,  S9 = 25,  S10= 26,  S11= 27,  T3 = 28,  T4 = 29,  T5 = 30,  T6 = 31;
 
     // FP registers
-    static final int F0   = 32,  F1  = 33,  F2  = 34,  F3  = 35,  F4  = 36,  F5  = 37,  F6  = 38,  F7   = 39;
-    static final int FS0  = 40,  FS1 = 41,  FA0 = 42,  FA1 = 43,  FA2 = 44,  FA3 = 45,  FA4 = 46,  FA5  = 47;
-    static final int FA6  = 48,  FA7 = 49,  FS2 = 50,  FS3 = 51,  FS4 = 52,  FS5 = 53,  FS6 = 54,  FS7  = 55;
-    static final int FS8  = 56,  FS9 = 57,  FS10 = 58, FS11 = 59, FT8 = 60,  FT9 = 61,  FT10 = 62, FT11 = 63;
+    public static int F0   = 32,  F1  = 33,  F2  = 34,  F3  = 35,  F4  = 36,  F5  = 37,  F6  = 38,  F7   = 39;
+    public static int FS0  = 40,  FS1 = 41,  FA0 = 42,  FA1 = 43,  FA2 = 44,  FA3 = 45,  FA4 = 46,  FA5  = 47;
+    public static int FA6  = 48,  FA7 = 49,  FS2 = 50,  FS3 = 51,  FS4 = 52,  FS5 = 53,  FS6 = 54,  FS7  = 55;
+    public static int FS8  = 56,  FS9 = 57,  FS10 = 58, FS11 = 59, FT8 = 60,  FT9 = 61,  FT10 = 62, FT11 = 63;
+
+    static final int MAX_REG = 64;
 
-    static final int MAX_REG = 61;
+    public static final int F_OFFSET = 32;
 
     static final String[] REGS = new String[] {
-        "zero", "r1"  , "rsp" , "r3"  , "r4"  , "r5"  , "r6"  , "r7"  ,
-        "r8"  , "r9"  , "r10" , "r11" , "r12" , "r13" , "r14" , "r15" ,
-        "r16" , "r17" , "r18" , "r19" , "r20" , "r21" , "r22" , "r23" ,
-        "r24" , "r25" , "r26" , "r27" , "r28" , "r29" , "r30" , "r31" ,
+        "zero","rpc"  , "rsp" , "s12" , "s13" , "t0"  , "t1"  , "t2"  ,
+        "s0"  , "s1"  , "a0"  , "a1"  , "a2"  , "a3"  , "a4"  , "a5"  ,
+        "a6"  , "a7"  , "s2"  , "s3"  , "s4"  , "s5"  , "s6"  , "s7"  ,
+        "s8"  , "s9"  , "s10" , "s11" , "t3"  , "t4"  , "t5"  , "t6"  ,
         "f0"  , "f1"  , "f2"  , "f3"  , "f4"  , "f5"  , "f6"  , "f7"  ,
         "fs0" , "fs1" , "fa0" , "fa1" , "fa2" , "fa3" , "fa4" , "fa5" ,
         "fa6" , "fa7" , "fs2" , "fs3" , "fs4" , "fs5" , "fs6" , "fs7" ,
         "fs8" , "fs9" , "fs10", "fs11", "ft8" , "ft9" , "ft10", "ft11"
+        // Register-based naming hella easier to debug than "official" register
+        // names when single-stepping in debugger.
+        //"zero", "r1"  , "rsp" , "r3" , "r4" , "r5" , "r6" , "r7" ,
+        //"r8"  , "r9"  , "r10" , "r11", "r12", "r13", "r14", "r15",
+        //"r16" , "r17" , "r18" , "r19", "r20", "r21", "r22", "r23",
+        //"r24" , "r25" , "r26" , "r27", "r28", "r29", "r30", "r31",
+        //"f0"  , "f1"  , "f2"  , "f3"  , "f4"  , "f5"  , "f6"  , "f7"  ,
+        //"fs0" , "fs1" , "fa0" , "fa1" , "fa2" , "fa3" , "fa4" , "fa5" ,
+        //"fa6" , "fa7" , "fs2" , "fs3" , "fs4" , "fs5" , "fs6" , "fs7" ,
+        //"fs8" , "fs9" , "fs10", "fs11", "ft8" , "ft9" , "ft10", "ft11"
     };
-    @Override public String reg( int reg ) {
-        return reg < REGS.length ? REGS[reg] : "[rsp+"+(reg-REGS.length)*4+"]";
-    }
-
+    @Override public String[] regs() { return REGS; }
 
     // General purpose register mask: pointers and ints, not floats
     static final long RD_BITS = 0b11111111111111111111111111111111L; // All the GPRs
     static final RegMask RMASK = new RegMask(RD_BITS);
 
-    static final long WR_BITS = 0b11111111111111111111111111111010L; // All the GPRs, minus ZERO and SP
+    static final long WR_BITS = 0b11111111111111111111111111111010L; // All the GPRs, minus ZERO and RSP
     static final RegMask WMASK = new RegMask(WR_BITS);
     // Float mask from(f0-ft10).  TODO: ft10,ft11 needs a larger RegMask
     static final long FP_BITS = 0b11111111111111111111111111111111L<<F0;
@@ -56,26 +70,26 @@ public class riscv extends Machine {
 
 
     // Arguments masks
-    static final RegMask A0_MASK = new RegMask(A0);
-    static final RegMask A1_MASK = new RegMask(A1);
-    static final RegMask A2_MASK = new RegMask(A2);
-    static final RegMask A3_MASK = new RegMask(A3);
-    static final RegMask A4_MASK = new RegMask(A4);
-    static final RegMask A5_MASK = new RegMask(A5);
-    static final RegMask A6_MASK = new RegMask(A6);
-    static final RegMask A7_MASK = new RegMask(A7);
+    public static RegMask A0_MASK = new RegMask(A0);
+    public static RegMask A1_MASK = new RegMask(A1);
+    public static RegMask A2_MASK = new RegMask(A2);
+    public static RegMask A3_MASK = new RegMask(A3);
+    public static RegMask A4_MASK = new RegMask(A4);
+    public static RegMask A5_MASK = new RegMask(A5);
+    public static RegMask A6_MASK = new RegMask(A6);
+    public static RegMask A7_MASK = new RegMask(A7);
 
-    static final RegMask RPC_MASK = new RegMask(RPC);
+    public static final RegMask RPC_MASK = new RegMask(RPC);
 
     // Float arguments masks
-    static final RegMask FA0_MASK = new RegMask(FA0);
-    static final RegMask FA1_MASK = new RegMask(FA1);
-    static final RegMask FA2_MASK = new RegMask(FA2);
-    static final RegMask FA3_MASK = new RegMask(FA3);
-    static final RegMask FA4_MASK = new RegMask(FA4);
-    static final RegMask FA5_MASK = new RegMask(FA5);
-    static final RegMask FA6_MASK = new RegMask(FA6);
-    static final RegMask FA7_MASK = new RegMask(FA7);
+    public static RegMask FA0_MASK = new RegMask(FA0);
+    public static RegMask FA1_MASK = new RegMask(FA1);
+    public static RegMask FA2_MASK = new RegMask(FA2);
+    public static RegMask FA3_MASK = new RegMask(FA3);
+    public static RegMask FA4_MASK = new RegMask(FA4);
+    public static RegMask FA5_MASK = new RegMask(FA5);
+    public static RegMask FA6_MASK = new RegMask(FA6);
+    public static RegMask FA7_MASK = new RegMask(FA7);
 
     // Int arguments calling conv
     static RegMask[] CALLINMASK = new RegMask[] {
@@ -90,17 +104,157 @@ public class riscv extends Machine {
     };
 
     static RegMask[] XMMS = new RegMask[] {
-            FA0_MASK,
-            FA1_MASK,
-            FA2_MASK,
-            FA3_MASK,
-            FA4_MASK,
-            FA5_MASK,
-            FA6_MASK,
-            FA7_MASK
+        FA0_MASK,
+        FA1_MASK,
+        FA2_MASK,
+        FA3_MASK,
+        FA4_MASK,
+        FA5_MASK,
+        FA6_MASK,
+        FA7_MASK
     };
 
-    static RegMask callInMask( TypeFunPtr tfp, int idx ) {
+    // major opcode: OP
+    public static int OP_LOAD    = 0b00_000_11;
+    public static int OP_LOADFP  = 0b00_001_11;
+    public static int OP_CUSTOM0 = 0b00_010_11;
+    public static int OP_IMM     = 0b00_100_11;
+    public static int OP_AUIPC   = 0b00_101_11;
+
+    public static int OP_STORE   = 0b01_000_11;
+    public static int OP_STOREFP = 0b01_001_11;
+    public static int OP_CUSTOM1 = 0b01_010_11;
+    public static int OP         = 0b01_100_11;
+    public static int OP_LUI     = 0b01_101_11;
+
+    public static int OP_CUSTOM2 = 0b10_010_11;
+    public static int OP_FP      = 0b10_100_11;
+
+    public static int OP_BRANCH  = 0b11_000_11;
+    public static int OP_JALR    = 0b11_001_11;
+    public static int OP_RESERVED= 0b11_010_11;
+    public static int OP_JAL     = 0b11_011_11;
+
+
+    // Since riscv instructions are fixed we can just or them together
+    public static int r_type(int opcode, int rd, int func3, int rs1, int rs2, int func7) {
+        assert 0 <= rs1 && rs1 < 32;
+        assert 0 <= rs2 && rs2 < 32;
+        assert 0 <= rd &&  rd  < 32;
+        return (func7 << 25) | (rs2 << 20) | (rs1 << 15) | (func3 << 12) | (rd << 7) | opcode;
+    }
+    public static void r_type(Encoding enc, Node n, int func3, int func7) {
+        short dst  = enc.reg(n);
+        short src1 = enc.reg(n.in(1));
+        short src2 = enc.reg(n.in(2));
+        int body = r_type(OP,dst,func3,src1,src2,func7);
+        enc.add4(body);
+    }
+
+    public static void rf_type(Encoding enc, Node n, RM func3, int func7) {
+        short dst  = (short)(enc.reg(n      )-F_OFFSET);
+        short src1 = (short)(enc.reg(n.in(1))-F_OFFSET);
+        short src2 = (short)(enc.reg(n.in(2))-F_OFFSET);
+        int body = r_type(OP_FP,dst,func3.ordinal(),src1,src2,func7);
+        enc.add4(body);
+    }
+
+
+    public static int u_type(int opcode, int rd, int imm20) {
+        assert 0 <= rd && rd < 32;
+        return (imm20 << 12) | (rd << 7) | opcode;
+    }
+
+    public static int j_type(int opcode, int rd, int delta) {
+        assert -(1L<<20) <= delta && delta < (1L<<20);
+        assert 0 <= rd && rd < 32;
+        // Messy branch offset encoding
+        // 31 30-21 20 19-12 11-7  6-0
+        // 20 10- 1 11 19-12 rpc   JAL
+        assert (delta&1)==0;    // Low bit is always zero, not encoded
+        int imm10_01 = (delta>> 1) & 0x3FF;
+        int imm11    = (delta>>11) &     1;
+        int imm12_19 = (delta>>12) &  0xFF;
+        int imm20    = (delta>>19) &     1;
+        int bits = imm20<<19 | imm10_01 << 9 | imm11 << 8 | imm12_19;
+        return bits << 12 | rd << 7 | opcode;
+    }
+
+
+    public static int i_type(int opcode, int rd, int func3, int rs1, int imm12) {
+        assert 0 <= rd  &&  rd  < 32;
+        assert 0 <= rs1 &&  rs1 < 32;
+        assert opcode >= 0 && func3 >=0 && imm12 >= 0; // Zero-extend by caller
+        return  (imm12 << 20) | (rs1 << 15) | (func3 << 12) | (rd << 7) | opcode;
+    }
+
+
+    // S-type instructions(store)
+    public static int s_type(int opcode, int func3, int rs1, int rs2, int imm12) {
+        assert 0 <= rs1 &&  rs1 < 32;
+        assert 0 <= rs2 &&  rs2 < 32;
+        assert 0 <= func3;
+
+        assert imm12 >= 0;      // Masked to high zero bits by caller
+        int imm_lo = imm12 & 0x1F;
+        int imm_hi = imm12 >> 5;
+        return (imm_hi << 25) | (rs2 << 20) | (rs1 << 15) | (func3 << 12) | (imm_lo << 7) | opcode;
+    }
+
+    // BRANCH
+    public static int b_type(int opcode, int func3, short rs1, short rs2, int delta) {
+        assert 0 <= rs1 && rs1 < 32;
+        assert 0 <= rs2 && rs2 < 32;
+        assert -4*1024 <= delta && delta < 4*1024;
+        assert (delta&1)==0;    // Low bit is always zero, not encoded
+        // Messy branch offset encoding
+        // 31 30 29 28 27 26 25 24-20 19-15 14-12 11 10  9  8  7  6-0
+        // 12 10  9  8  7  6  5 SRC2  SRC1  FUNC3  4  3  2  1 11  OP
+        int imm4_1 = (delta>> 1) & 0xF;
+        int imm10_5= (delta>> 5) &0x3F;
+        int imm11  = (delta>>11) &   1;
+        int imm12  = (delta>>12) &   1;
+        int imm5 = imm4_1<<1 | imm11;
+        int imm7 = imm12<<6 | imm10_5;
+        return (imm7 << 25 ) | (rs2 << 20) | (rs1 << 15) | (func3 << 12) | (imm5 << 7) | opcode;
+    }
+
+    public enum RM {
+        RNE,       // Round to Nearest, ties to Even
+        RTZ,       // Round towards Zero
+        RDN,       // Round Down
+        RUP,       // Round Up
+        DIRECT,    // Round to Nearest, ties to Max Magnitude
+        RESERVED1, // Reserved for futue use
+        RESERVED2, // Reserved for future use
+        DYN,       // In instruction’s rm field, selects dynamic rounding mode; In Rounding Mode register, reserved
+    }
+
+    // Since opcode is the same just return back func3
+    static public int jumpop(String op) {
+        return switch(op) {
+        case "=="  -> 0x0;
+        case "!="  -> 0x1;
+        case "<"   -> 0x4;
+        case ">="  -> 0x5;
+        case "u<"  -> 0x6;
+        case "u<=" -> 0x7;
+        default  ->  throw Utils.TODO();
+        };
+    }
+
+    // Since opcode is the same just return back func3
+    static public int fsetop(String op) {
+        return switch(op) {
+        case "<"  -> 1;
+        case "<=" -> 0;
+        case "==" -> 2;
+        default   -> throw Utils.TODO();
+        };
+    }
+
+    @Override public RegMask callArgMask( TypeFunPtr tfp, int idx, int maxArgSlot ) { return callInMask(tfp,idx,maxArgSlot); }
+    static RegMask callInMask( TypeFunPtr tfp, int idx, int maxArgSlot ) {
         if( idx==0 ) return RPC_MASK;
         if( idx==1 ) return null;
         // Count floats in signature up to index
@@ -117,109 +271,94 @@ public class riscv extends Machine {
             if( idx-2-fcnt < cargs.length )
                 return cargs[idx-2-fcnt];
         }
-        throw Utils.TODO(); // Pass on stack slot
-    }
-
-    // callee saved(riscv)
-    static final long CALLEE_SAVE =
-        (1L<< S0) | (1L<< S1) | (1L<< S2 ) | (1L<< S3 ) |
-        (1L<< S4) | (1L<< S5) | (1L<< S6 ) | (1L<< S7 ) |
-        (1L<< S8) | (1L<< S9) | (1L<< S10) | (1L<< S11) |
-        (1L<<FS0) | (1L<<FS1) | (1L<<FS2 ) | (1L<<FS3 ) |
-        (1L<<FS4) | (1L<<FS5) | (1L<<FS6 ) | (1L<<FS7 ) |
-        (1L<<FS8) | (1L<<FS9) | (1L<<FS10) | (1L<<FS11);
-
-    static final RegMask CALLER_SAVE_MASK;
-    static {
-        long caller = ~CALLEE_SAVE;
-        caller &= ~(1L<<SP);
-        CALLER_SAVE_MASK = new RegMask(caller,0);
-    }
-    static RegMask riscCallerSave() { return CALLER_SAVE_MASK; }
-    @Override public RegMask callerSave() { return riscCallerSave(); }
-
-    static final RegMask CALLEE_SAVE_MASK = new RegMask(CALLEE_SAVE);
-    static RegMask riscCalleeSave() { return CALLEE_SAVE_MASK; }
-    @Override public RegMask calleeSave() { return riscCalleeSave(); }
-
-    // Return single int/ptr register.  Used by CallEnd output and Return input.
-    static final RegMask[] RET_MASKS;
-    static {
-        int nSaves = CALLEE_SAVE_MASK.size();
-        RET_MASKS = new RegMask[4 + nSaves];
-        RET_MASKS[0] = null;
-        RET_MASKS[1] = null;     // Memory
-        RET_MASKS[2] = null;     // Varies, either XMM0 or RAX
-        RET_MASKS[3] = RMASK;    // Expected R1 but could be any register really
-        short reg = CALLEE_SAVE_MASK.firstReg();
-        for( int i=0; i<nSaves; i++ ) {
-            RET_MASKS[i+4] = new RegMask(reg);
-            reg = CALLEE_SAVE_MASK.nextReg(reg);
+        // Pass on stack slot(8 and higher)
+        if( maxArgSlot>0 ) throw Utils.TODO();
+        return new RegMask(MAX_REG + 1 + (idx - 2));
+    }
+
+    @Override public short maxArgSlot( TypeFunPtr tfp ) {
+        int icnt=0, fcnt=0;     // Count of ints, floats
+        for( int i=0; i<tfp.nargs(); i++ ) {
+            if( tfp.arg(i) instanceof TypeFloat ) fcnt++;
+            else icnt++;
         }
+        int nstk = Math.max(icnt-8,0)+Math.max(fcnt-8,0);
+        return (short)nstk;
     }
-    static RegMask retMask( TypeFunPtr tfp, int i ) {
-        return i==2
-            ? (tfp.ret() instanceof TypeFloat ? FA0_MASK : A0_MASK)
-            : RET_MASKS[i];
+
+    static final long CALLER_SAVE =
+        (1L<<RPC) |
+        (1L<<A0 ) | (1L<<A1 ) | (1L<<A2 ) | (1L<<A3 ) | (1L<<A4 ) | (1L<<A5 ) | (1L<<A6 ) | (1L<<A7 ) |
+        (1L<<T0 ) | (1L<<T1 ) | (1L<<T2 ) | (1L<<T3 ) | (1L<<T4 ) | (1L<<T5 ) | (1L<<T6 ) |
+        (1L<<FA0) | (1L<<FA1) | (1L<<FA2) | (1L<<FA3) | (1L<<FA4) | (1L<<FA5) | (1L<<FA6) | (1L<<FA7) |
+        (1L<<F0 ) | (1L<<F1 ) | (1L<<F2 ) | (1L<<F3 ) | (1L<<F4 ) | (1L<<F5 ) | (1L<<F6 ) | (1L<<F7 ) |
+        (1L<<FT8) | (1L<<FT9) | (1L<<FT10)| (1L<<FT11);
+
+    @Override public long callerSave() { return CALLER_SAVE; }
+    @Override public long  neverSave() { return (1L<<RSP) | (1L<<ZERO); }
+    @Override public RegMask retMask( TypeFunPtr tfp ) {
+        return tfp.ret() instanceof TypeFloat ? FA0_MASK : A0_MASK;
     }
+    @Override public int rpc() { return RPC; }
 
 
     // Return a MachNode unconditional branch
-    @Override public CFGNode jump() {
-        throw Utils.TODO();
-    }
+    @Override public CFGNode jump() { return new UJmpRISC(); }
 
     // Create a split op; any register to any register, including stack slots
     @Override  public SplitNode split(String kind, byte round, LRG lrg) { return new SplitRISC(kind,round);  }
 
-    // Break an infinite loop
-    @Override public IfNode never( CFGNode ctrl ) {
-        throw Utils.TODO();
-    }
-
     // True if signed 12-bit immediate
-    private static boolean imm12(TypeInteger ti) {
-        // 64-12==52
+    public static boolean imm12(TypeInteger ti) {
+        // 52 = 64-12
         return ti.isConstant() && ((ti.value()<<52)>>52) == ti.value();
     }
-
+    // True if HIGH 20-bit signed immediate, with all zeros low.
+    public static boolean imm20Exact(TypeInteger ti) {
+        // shift left 32 to clear out the upper 32 bits.
+        // shift right SIGNED to sign-extend upper 32 bits; then shift 12 more to clear out lower 12 bits.
+        // shift left 12 to re-center the bits.
+        return ti.isConstant() && (((ti.value()<<32)>>>44)<<12) == ti.value();
+    }
 
     @Override public Node instSelect( Node n ) {
         return switch (n) {
-        case AddFNode addf -> addf(addf);
-        case AddNode add -> add(add);
-        case AndNode and -> and(and);
-        case BoolNode bool -> cmp(bool);
-        case CallNode call -> call(call);
-        case CastNode cast  -> new CastRISC(cast);
+        case AddFNode    addf -> addf(addf);
+        case AddNode      add -> add(add);
+        case AndNode      and -> and(and);
+        case BoolNode    bool -> cmp(bool);
+        case CallNode    call -> call(call);
+        case CastNode   cast  -> new CastRISC(cast);
         case CallEndNode cend -> new CallEndRISC(cend);
-        case CProjNode c -> new CProjNode(c);
+        case CProjNode      c -> new CProjNode(c);
         case ConstantNode con -> con(con);
-        case DivFNode divf -> new DivFRISC(divf);
-        case DivNode div -> new DivRISC(div);
-        case FunNode fun -> new FunRISC(fun);
-        case IfNode iff -> jmp(iff);
-        case LoadNode ld -> ld(ld);
+        case DivFNode    divf -> new DivFRISC(divf);
+        case DivNode      div -> new DivRISC(div);
+        case FunNode      fun -> new FunRISC(fun);
+        case IfNode       iff -> jmp(iff);
+        case LoadNode      ld -> ld(ld);
         case MemMergeNode mem -> new MemMergeNode(mem);
-        case MulFNode mulf -> new MulFRISC(mulf);
-        case MulNode mul -> new MulRISC(mul);
-        case NewNode nnn -> new NewRISC(nnn);
-        case OrNode or -> or(or);
-        case ParmNode parm -> new ParmRISC(parm);
-        case PhiNode phi -> new PhiNode(phi);
-        case ProjNode prj -> prj(prj);
-        case ReadOnlyNode read -> new ReadOnlyNode(read);
-        case ReturnNode ret -> new RetRISC(ret, ret.fun());
-        case SarNode sar -> sra(sar);
-        case ShlNode shl -> sll(shl);
-        case ShrNode shr -> srl(shr);
-        case StartNode start -> new StartNode(start);
-        case StopNode stop -> new StopNode(stop);
-        case StoreNode st -> st(st);
-        case SubFNode subf -> new SubFRISC(subf);
-        case SubNode sub -> sub(sub);
-        case ToFloatNode tfn -> i2f8(tfn);
-        case XorNode xor -> xor(xor);
+        case MinusNode    neg -> new NegRISC(neg);
+        case MulFNode    mulf -> new MulFRISC(mulf);
+        case MulNode      mul -> new MulRISC(mul);
+        case NewNode      nnn -> nnn(nnn);
+        case NotNode      not -> new NotRISC(not);
+        case OrNode        or -> or(or);
+        case ParmNode    parm -> new ParmRISC(parm);
+        case PhiNode      phi -> new PhiNode(phi);
+        case ProjNode     prj -> prj(prj);
+        case ReadOnlyNode read-> new ReadOnlyNode(read);
+        case ReturnNode   ret -> new RetRISC(ret, ret.fun());
+        case SarNode      sar -> sra(sar);
+        case ShlNode      shl -> sll(shl);
+        case ShrNode      shr -> srl(shr);
+        case StartNode  start -> new StartNode(start);
+        case StopNode    stop -> new StopNode(stop);
+        case StoreNode     st -> st(st);
+        case SubFNode    subf -> new SubFRISC(subf);
+        case SubNode      sub -> sub(sub);
+        case ToFloatNode  tfn -> i2f8(tfn);
+        case XorNode      xor -> xor(xor);
 
         case LoopNode loop -> new LoopNode(loop);
         case RegionNode region -> new RegionNode(region);
@@ -232,36 +371,81 @@ public class riscv extends Machine {
     }
 
     private Node add(AddNode add) {
-        if( add.in(2) instanceof ConstantNode off && off._con instanceof TypeInteger ti && imm12(ti) )
-            return new AddIRISC(add, (int)ti.value());
+        if( add.in(2) instanceof ConstantNode off2 && off2._con instanceof TypeInteger ti && imm12(ti) )
+            return new AddIRISC(add, (int)ti.value(),true);
         return new AddRISC(add);
     }
 
     private Node and(AndNode and) {
-        if( and.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti) )
-            return new AndIRISC(and, (int)ti.value());
+        if( and.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti ) {
+            if( imm12(ti) )
+                return new AndIRISC(and, (int)ti.value());
+            // Could be any size low bit mask
+            if( ti.value() == 0xFFFFFFFFL )
+                return new SrlIRISC(new SllIRISC(and,32),32,false);
+        }
         return new AndRISC(and);
     }
 
     private Node call(CallNode call) {
-        if( call.fptr() instanceof ConstantNode con && con._con instanceof TypeFunPtr tfp )
-            return new CallRISC(call, tfp);
-        return new CallRRISC(call);
+        return call.fptr() instanceof ConstantNode con && con._con instanceof TypeFunPtr tfp
+            ? new CallRISC(call, tfp)
+            : new CallRRISC(call);
+    }
+    private Node nnn(NewNode nnn) {
+        // TODO: pass in the TFP for alloc
+        return new NewRISC(nnn);
     }
 
     private Node cmp(BoolNode bool) {
-        if( bool.in(2) instanceof ConstantNode off && off._con instanceof TypeInteger toff )
-            return new SetIRISC(bool, (int)toff.value());
-        // Float variant
+        // Float variant directly implemented in hardware
         if( bool.isFloat() )
             return new SetFRISC(bool);
-        return new SetRISC(bool);
+
+        // Only < and <u are implemented in hardware.
+        // x <  y - as-is
+        // x <= y - flip and negate; !(y < x); `slt tmp=y,x; xori dst=tmp,#1`
+        // x == y - sub and vs0 == `sub tmp=x-y; sltu dst=tmp,#1`
+
+        // x >  y - swap; y < x
+        // x >= y - swap and negate; !(x < y); `slt tmp=y,x;` then NOT.
+        // x != y - sub and vs0 == `sub tmp=x-y; sltu dst=tmp,#1` then NOT.
+
+        // The ">", ">=" and "!=" in Simple include a NotNode, which can be
+        // implemented with a XOR.  If one of the above is followed by a NOT
+        // we can remove the double XOR in the encodings.
+
+        return switch( bool.op() ) {
+        case "<" -> bool.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti)
+            ? new SetIRISC(bool, (int)ti.value(),false)
+            : new  SetRISC(bool, false);
+        // x <= y - flip and negate; !(y < x); `slt tmp=y,x; xori dst=tmp,#1`
+        case "<=" -> new XorIRISC(new SetRISC(bool.swap12(), false),1);
+        // x == y - sub and vs0 == `sub tmp=x-y; sltu dst=tmp,#1`
+        case "==" -> new SetIRISC(new SubRISC(bool),1,true);
+        default -> throw Utils.TODO();
+        };
     }
 
     private Node con( ConstantNode con ) {
         if( !con._con.isConstant() ) return new ConstantNode( con ); // Default unknown caller inputs
         return switch( con._con ) {
-        case TypeInteger ti  -> new IntRISC(con);
+        case TypeInteger ti -> {
+            if( imm12(ti) ) yield new IntRISC(con);
+            long x = ti.value();
+            if( imm20Exact(ti) ) yield new LUI((int)x);
+            if( (x<<32)>>32 == x ) { // Signed lower 32-bit immediate
+                // Here, the low 12 bits get sign-extended, which means if
+                // bit11 is set, the value is negative and lowers the LUI
+                // value.  Add a bit 12 to compensate
+                if( ((x>>11)&1)==1 ) x += 0x1000;
+                yield new AddIRISC(new LUI((int)(x & ~0xFFF)), (int)(x & 0xFFF),false);
+            }
+            // Need more complex sequence for larger constants... or a load
+            // from a constant pool, which does not need an extra register
+            throw Utils.TODO();
+        }
+        // Load from constant pool
         case TypeFloat   tf  -> new FltRISC(con);
         case TypeFunPtr  tfp -> new TFPRISC(con);
         case TypeMemPtr  tmp -> throw Utils.TODO();
@@ -272,45 +456,50 @@ public class riscv extends Machine {
     }
 
     private Node jmp( IfNode iff ) {
-        if( iff.in(1) instanceof BoolNode bool && !bool.isFloat() )
-            return new BranchRISC(iff, bool.op(), bool.in(1), bool.in(2));
+        if( iff.in(1) instanceof BoolNode bool && !bool.isFloat() ) {
+            // if less than or equal switch inputs
+            String bop = bool.op();
+            if( bop.equals("<=") || bop.equals(">") )
+                return new BranchRISC(iff, IfNode.swap(bop), bool.in(2), bool.in(1));
+            return new BranchRISC(iff, bop, bool.in(1), bool.in(2));
+        }
         // Vs zero
-        return new BranchRISC(iff, "==", iff.in(1), null);
+        return new BranchRISC(iff, iff.in(1)==null ? "==" : "!=", iff.in(1), null);
     }
 
     private Node or(OrNode or) {
-        if( or.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti) )
+        if( or.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti))
             return new OrIRISC(or, (int)ti.value());
         return new OrRISC(or);
     }
 
     private Node xor(XorNode xor) {
-        if( xor.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti) )
+        if( xor.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti))
             return new XorIRISC(xor, (int)ti.value());
         return new XorRISC(xor);
     }
 
     private Node sra(SarNode sar) {
-        if( sar.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti) )
+        if( sar.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti))
             return new SraIRISC(sar, (int)ti.value());
         return new SraRISC(sar);
     }
 
     private Node srl(ShrNode shr) {
-        if( shr.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti) )
-            return new SrlIRISC(shr, (int)ti.value());
+        if( shr.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti))
+            return new SrlIRISC(shr, (int)ti.value(),true);
         return new SrlRISC(shr);
     }
 
     private Node sll(ShlNode sll) {
-        if( sll.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti) )
+        if( sll.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti))
             return new SllIRISC(sll, (int)ti.value());
         return new SllRISC(sll);
     }
 
     private Node sub(SubNode sub) {
         return sub.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti)
-            ? new AddIRISC(sub, (int)(-ti.value()))
+            ? new AddIRISC(sub, (int)(-ti.value()),true)
             : new SubRISC(sub);
     }
 
@@ -324,28 +513,20 @@ public class riscv extends Machine {
     }
 
     private Node ld(LoadNode ld) {
-        return new LoadRISC(address(ld),ld.ptr(),idx,off);
+        return new LoadRISC(ld,address(ld),off);
     }
 
     private Node st(StoreNode st) {
-        int imm=0;
-        Node xval = st.val();
-        if( xval instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti) ) {
-            xval = null;
-            imm = (int)ti.value();
-            assert imm == ti.value(); // In 32-bit range
-        }
-        return new StoreRISC(address(st),st.ptr(),idx,off,imm,xval);
+        Node xval = st.val() instanceof ConstantNode con && con._con == TypeInteger.ZERO ? null : st.val();
+        return new StoreRISC(st,address(st), off, xval);
     }
 
     // Gather addressing mode bits prior to constructing.  This is a builder
     // pattern, but saving the bits in a *local* *global* here to keep mess
     // contained.
     private static int off;
-    private static Node idx;
-    private <N extends MemOpNode> N address( N mop ) {
+    private Node address( MemOpNode mop ) {
         off = 0;  // Reset
-        idx = null;
         Node base = mop.ptr();
         // Skip/throw-away a ReadOnly, only used to typecheck
         if( base instanceof ReadOnlyNode read ) base = read.in(1);
@@ -353,9 +534,10 @@ public class riscv extends Machine {
         if( mop.off() instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm12(ti) ) {
             off = (int)ti.value();
         } else {
-            idx = mop.off();
+            base = new AddRISC(base,mop.off());
+            base._type = mop.ptr()._type;
         }
-        return mop;
+        return base;
     }
 
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddFMemX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddFMemX86.java
index ffc6966e..d54c7c31 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddFMemX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddFMemX86.java
@@ -2,15 +2,14 @@ package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 
 public class AddFMemX86 extends MemOpX86 {
     AddFMemX86( AddFNode add, LoadNode ld , Node base, Node idx, int off, int scale, Node val ) {
         super(add,ld, base, idx, off, scale, 0, val );
     }
-
+    @Override public String op() { return "addf"+_sz; }
     @Override public RegMask regmap(int i) {
         if( i==1 ) return null;            // Memory
         if( i==2 ) return x86_64_v2.RMASK; // base
@@ -18,10 +17,23 @@ public class AddFMemX86 extends MemOpX86 {
         if( i==4 ) return x86_64_v2.XMASK; // value
         throw Utils.TODO();
     }
-
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return x86_64_v2.XMASK; }
+    @Override public int twoAddress() { return 4; }
+    @Override public void encoding( Encoding enc ) {
+        //  addsd xmm0, DWORD PTR [rdi+0xc]
+        short dst = enc.reg(this );
+        short ptr = enc.reg(ptr());
+        short idx = enc.reg(idx());
+        // F opcode
+        enc.add1(0xF2);
+        // rex prefix must come next (REX.W is not set)
+        x86_64_v2.rexF(dst, ptr, idx, false, enc);
 
+        // FP ADD
+        enc.add1(0x0F).add1(0x58);
+
+        x86_64_v2.indirectAdr(_scale, idx, ptr, _off, dst, enc);
+    }
 
     // General form: "add  dst = src + [base + idx<<2 + 12]"
     @Override public void asm(CodeGen code, SB sb) {
@@ -29,5 +41,4 @@ public class AddFMemX86 extends MemOpX86 {
         sb.p(val()==null ? "#"+_imm : code.reg(val())).p(" + ");
         asm_address(code,sb);
     }
-    @Override public String op() { return "addf"+_sz; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddFX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddFX86.java
index d4ea9162..a4166bc7 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddFX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddFX86.java
@@ -1,33 +1,33 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class AddFX86 extends MachConcreteNode implements MachNode {
     AddFX86( Node addf ) { super(addf); }
-
-    // Register mask allowed on input i.
+    @Override public String op() { return "addf"; }
     @Override public RegMask regmap(int i) { assert i==1 || i==2; return x86_64_v2.XMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return x86_64_v2.XMASK; }
-    // Output is same register as input#1
     @Override public int twoAddress() { return 1; }
-    // Ok to swap arguments
     @Override public boolean commutes() { return true; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        // F2 0F 58 /r ADDSD xmm1, xmm2/m64
+        short dst = (short)(enc.reg(this ) - x86_64_v2.XMM_OFFSET);
+        short src = (short)(enc.reg(in(2)) - x86_64_v2.XMM_OFFSET);
+        // Fopcode
+        enc.add1(0xF2);
+        // rex prefix must come next (REX.W is not set)
+        x86_64_v2.rexF(dst, src, 0, false, enc);
+
+        enc.add1(0x0F).add1(0x58);
+
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, src));
     }
 
     // General form: "addf  dst += src"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" + ").p(code.reg(in(2)));
+        sb.p(code.reg(this)).p(" += ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "addf"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddIX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddIX86.java
index c7f92ff1..569be754 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddIX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddIX86.java
@@ -1,41 +1,13 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-
-public class AddIX86 extends MachConcreteNode implements MachNode {
-    final TypeInteger _ti;
-    AddIX86( Node add, TypeInteger ti ) {
-        super(add);
-        _inputs.pop();
-         _ti = ti;
-    }
-
-    // Register mask allowed on input i.
-    @Override public RegMask regmap(int i) {
-        // assert i== i;
-        return x86_64_v2.WMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form: "addi  dst += #imm"
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" + #");
-        _ti.print(sb);
-    }
+import com.seaofnodes.simple.node.Node;
 
+public class AddIX86 extends ImmX86 {
+    AddIX86( Node add, int imm ) { super(add,imm); }
     @Override public String op() {
-        return _ti.value() == 1  ? "inc" : (_ti.value() == -1 ? "dec" : "addi");
+        return _imm == 1  ? "inc" : (_imm == -1 ? "dec" : "addi");
     }
+    @Override public String glabel() { return "+"; }
+    @Override int opcode() { return 0x81; }
+    @Override int mod() { return 0; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddMemX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddMemX86.java
index 3d4fac41..f97a7cb8 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddMemX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddMemX86.java
@@ -1,26 +1,34 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 
 public class AddMemX86 extends MemOpX86 {
     AddMemX86( AddNode add, LoadNode ld , Node base, Node idx, int off, int scale, int imm, Node val ) {
         super(add,ld, base, idx, off, scale, imm, val );
     }
-
     @Override public String op() { return "add"+_sz; }
-
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-    // Output is same register as val()
     @Override public int twoAddress() { return 4; }
+    @Override public void encoding( Encoding enc ) {
+        // add something to register from memory
+        // add   eax,DWORD PTR [rdi+0xc]
+        // REX.W + 03 /r	ADD r64, r/m64
+        short dst = enc.reg(this );
+        short ptr = enc.reg(ptr());
+        short idx = enc.reg(idx());
+
+        enc.add1(x86_64_v2.rex(dst, ptr, idx));
+        // opcode
+        enc.add1(0x03);
+
+        x86_64_v2.indirectAdr(_scale, idx, ptr, _off, dst, enc);
+    }
 
-    // General form: "add  dst = src + [base + idx<<2 + 12]"
+    // General form: "add  dst += [base + idx<<2 + 12]"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ");
-        sb.p(val()==null ? "#"+_imm : code.reg(val())).p(" + ");
+        sb.p(code.reg(this)).p(" += ");
         asm_address(code,sb);
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddX86.java
index 9553d499..84543e8f 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AddX86.java
@@ -1,33 +1,11 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.node.Node;
 
-public class AddX86 extends MachConcreteNode {
+public class AddX86 extends RegX86 {
     AddX86( Node add ) { super(add); }
-
-    // Register mask allowed on input i.
-    @Override public RegMask regmap(int i) { assert i==1 || i==2; return x86_64_v2.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-    // Ok to swap arguments
-    @Override public boolean commutes() { return true; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form: "add  dst += src"
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" + ").p(code.reg(in(2)));
-    }
-
     @Override public String op() { return "add"; }
+    @Override public String glabel() { return "+"; }
+    @Override int opcode() { return 0x03; }
+    @Override public boolean commutes() { return true; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AndIX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AndIX86.java
index a7f1801e..3c1b567c 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AndIX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AndIX86.java
@@ -1,44 +1,11 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
-import java.lang.StringBuilder;
-
-public class AndIX86 extends MachConcreteNode implements MachNode {
-    final TypeInteger _ti;
-    AndIX86(Node and, TypeInteger ti) {
-    super(and);
-    _inputs.pop();
-    _ti = ti;
-    }
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) { assert i==1; return x86_64_v2.WMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form: "andi  dst & #imm"
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" & #");
-        _ti.print(sb);
-    }
+import com.seaofnodes.simple.node.Node;
 
+public class AndIX86 extends ImmX86 {
+    AndIX86( Node add, int imm ) { super(add,imm); }
     @Override public String op() { return "andi"; }
+    @Override public String glabel() { return "&"; }
+    @Override int opcode() { return 0x81; }
+    @Override int mod() { return 4; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AndX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AndX86.java
index d7fb3613..dedbce45 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AndX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/AndX86.java
@@ -1,34 +1,11 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.*;
-import java.io.ByteArrayOutputStream;
-
-public class AndX86  extends MachConcreteNode implements MachNode{
-    AndX86(Node and) {
-        super(and);
-    }
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) { assert i==1; return x86_64_v2.WMASK; }
-
-    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form: "and  dst & src"
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" & ").p(code.reg(in(2)));;
-    }
+import com.seaofnodes.simple.node.Node;
 
+public class AndX86 extends RegX86 {
+    AndX86( Node add ) { super(add); }
     @Override public String op() { return "and"; }
+    @Override public String glabel() { return "&"; }
+    @Override int opcode() { return 0x23; }
+    @Override public boolean commutes() { return true; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallEndX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallEndX86.java
index b9cc5659..ce8b993f 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallEndX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallEndX86.java
@@ -1,35 +1,8 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.node.CallEndNode;
 import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.type.TypeFloat;
-import com.seaofnodes.simple.type.TypeFunPtr;
-import java.io.ByteArrayOutputStream;
 
 public class CallEndX86 extends CallEndNode implements MachNode {
-    final TypeFunPtr _tfp;
-    CallEndX86( CallEndNode cend ) {
-        super(cend);
-        _tfp = (TypeFunPtr)(cend.call().fptr()._type);
-    }
-
-    @Override public String label() { return op(); }
-    @Override public RegMask regmap(int i) { return null; }
-    @Override public RegMask outregmap() { return null; }
-    @Override public RegMask outregmap(int idx) { return idx == 2 ? x86_64_v2.retMask(_tfp,2) : null; }
-    @Override public RegMask killmap() { return x86_64_v2.x86CallerSave(); }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    @Override public void asm(CodeGen code, SB sb) {  }
-
-    @Override public String op() { return "cend"; }
-
+    CallEndX86( CallEndNode cend ) { super(cend); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallRX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallRX86.java
index ac35d17b..1a74f817 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallRX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallRX86.java
@@ -1,32 +1,26 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.CallNode;
 import com.seaofnodes.simple.node.MachNode;
-import java.io.ByteArrayOutputStream;
 
 public class CallRX86 extends CallNode implements MachNode {
     CallRX86( CallNode call ) { super(call); }
-
+    @Override public String op() { return "callr"; }
     @Override public String label() { return op(); }
     @Override public RegMask regmap(int i) {
         return i==_inputs._len
             ? x86_64_v2.WMASK          // Function call target
-            : x86_64_v2.callInMask(tfp(),i); // Normal argument
+            : x86_64_v2.callInMask(tfp(),i,fun()._maxArgSlot); // Normal argument
     }
     @Override public RegMask outregmap() { return null; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        bytes.write(0xe8);
-        int beforeSize = bytes.size();
-        // address
-        //TODO: relocs
-        bytes.write(0x00);
-        return bytes.size() - beforeSize;
+    @Override public void encoding( Encoding enc ) {
+        // FF /2	CALL r/m64
+        // calls the function in the register
+        short src = enc.reg(fptr());
+        enc.add1(0xFF);
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.INDIRECT,2,src));
     }
 
     @Override public void asm(CodeGen code, SB sb) {
@@ -36,5 +30,4 @@ public class CallRX86 extends CallNode implements MachNode {
         sb.unchar(2);
     }
 
-    @Override public String op() { return "callr"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallX86.java
index e2f68c1f..c97037e2 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallX86.java
@@ -1,15 +1,12 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.CallNode;
 import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.type.TypeFunPtr;
-import java.io.ByteArrayOutputStream;
 
-public class CallX86 extends CallNode implements MachNode {
+public class CallX86 extends CallNode implements MachNode, RIPRelSize {
     final TypeFunPtr _tfp;
     final String _name;
     CallX86( CallNode call, TypeFunPtr tfp ) {
@@ -19,26 +16,24 @@ public class CallX86 extends CallNode implements MachNode {
         _tfp = tfp;
         _name = CodeGen.CODE.link(tfp)._name;
     }
-
+    @Override public String op() { return "call"; }
     @Override public String label() { return op(); }
-    @Override public RegMask regmap(int i) {
-        return x86_64_v2.callInMask(_tfp,i); // Normal argument
-    }
+    @Override public String name() { return _name; }
+    @Override public TypeFunPtr tfp() { return _tfp; }
+    @Override public RegMask regmap(int i) { return x86_64_v2.callInMask(_tfp,i,fun()._maxArgSlot);  }
     @Override public RegMask outregmap() { return null; }
     @Override public int nargs() { return nIns()-2; } // Minus control, memory, fptr
 
-    @Override public String name() { return _name; }
-    @Override public TypeFunPtr tfp() { return _tfp; }
+    @Override public void encoding( Encoding enc ) {
+        enc.relo(this).add1(0xe8).add4(0);
+    }
+
+    // Delta is from opcode start, but X86 measures from the end of the 5-byte encoding
+    @Override public byte encSize(int delta) { return 5; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        //  linker will fix this up
-        bytes.write(0xe8);
-        int beforeSize = bytes.size();
-        // TODO: relocs
-        // address
-        bytes.write(0x00);
-        return bytes.size() - beforeSize;
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        enc.patch4(opStart+1, delta-5);
     }
 
     @Override public void asm(CodeGen code, SB sb) {
@@ -47,7 +42,4 @@ public class CallX86 extends CallNode implements MachNode {
             sb.p(code.reg(in(i+2))).p("  ");
         sb.unchar(2);
     }
-
-    @Override public String op() { return "call"; }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CastX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CastX86.java
index b620b89c..9537cfb3 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CastX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CastX86.java
@@ -1,18 +1,16 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.CastNode;
 import com.seaofnodes.simple.node.MachNode;
-import java.io.ByteArrayOutputStream;
 
 public class CastX86 extends CastNode implements MachNode {
     CastX86( CastNode cast ) { super(cast); }
+    @Override public String op() { return label(); }
     @Override public RegMask regmap(int i) { assert i==1; return RegMask.FULL; }
     @Override public RegMask outregmap() { return RegMask.FULL; }
     @Override public int twoAddress( ) { return 1; }
-    @Override public int encoding(ByteArrayOutputStream bytes) { return 0; /*no encoding*/ }
+    @Override public void encoding( Encoding enc ) { }
     @Override public void asm(CodeGen code, SB sb) { _t.print(sb.p(code.reg(in(1))).p(" isa ")); }
-    @Override public String op() { return label(); }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpFX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpFX86.java
index e9b0dacd..35b92170 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpFX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpFX86.java
@@ -1,21 +1,26 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class CmpFX86 extends MachConcreteNode implements MachNode {
     CmpFX86( Node cmp ) { super(cmp); }
-
-    @Override public RegMask regmap(int i) { assert i==1 || i==2; return x86_64_v2.XMASK; }
+    @Override public String op() { return "cmpf"; }
+    @Override public RegMask regmap(int i) { return x86_64_v2.XMASK; }
     @Override public RegMask outregmap() { return x86_64_v2.FLAGS_MASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        // UCOMISD
+        short src1 = (short)(enc.reg(in(1)) - x86_64_v2.XMM_OFFSET);
+        short src2 = (short)(enc.reg(in(2)) - x86_64_v2.XMM_OFFSET);
+        // float opcode
+        enc.add1(0x66);
+        // rex prefix must come next (REX.W is not set)
+        x86_64_v2.rexF(src1, src2, 0, false, enc);
+
+        enc.add1(0x0F).add1(0x2E);
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, src1, src2));
     }
 
     // General form: "cmp src1,src2"
@@ -24,6 +29,4 @@ public class CmpFX86 extends MachConcreteNode implements MachNode {
         if( dst!="flags" )  sb.p(dst).p(" = ");
         sb.p(code.reg(in(1))).p(", ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "cmpf"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpIX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpIX86.java
index fcba397d..91b6d43c 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpIX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpIX86.java
@@ -1,53 +1,44 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 // Compare immediate.  Sets flags.
 public class CmpIX86 extends MachConcreteNode implements MachNode {
     final int _imm;
-    final String _bop;
-    CmpIX86( BoolNode bool, TypeInteger ti ) {
-        super(bool);
-        _inputs.pop(); // Toss ideal ConstantNode away, embedded into machine op
-        _bop = bool.op();       // One of <,<=,==
-        _imm = (int)ti.value();
-        assert _imm == ti.value();
+    CmpIX86( Node cmp, int imm, boolean swap ) {
+        super(cmp);
+        _inputs.del(swap ? 1 : 2);
+        _imm = imm;
     }
-    // Copy constructor does not set reverse edges in, because the basic block
-    // is changing from the original node - and it must be properly placed in a
-    // new block.
     CmpIX86( CmpIX86 cmp ) {
-        super(cmp);
-        _bop = cmp._bop;
+        super((Node)null);
+        addDef(null);
+        addDef(cmp.in(1));
         _imm = cmp._imm;
-        // While in(0) will be handled by the caller, all other edges must be
-        // handled in the constructor.
-        cmp.in(1)._outputs.push(this);
     }
 
-    @Override public RegMask regmap(int i) { assert i==1; return x86_64_v2.RMASK; }
+    @Override public String op() { return _imm==0 ? "test" : "cmp"; }
+    @Override public RegMask regmap(int i) { return x86_64_v2.RMASK; }
     @Override public RegMask outregmap() { return x86_64_v2.FLAGS_MASK; }
     @Override public boolean isClone() { return true; }
     @Override public Node copy() { return new CmpIX86(this); }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public final void encoding( Encoding enc ) {
+        short dst = enc.reg(in(1)); // Also src1
+        enc.add1(x86_64_v2.rex(0, dst, 0));
+        // opcode; 0x81 or 0x83; 0x69 or 0x6B
+        enc.add1( 0x81 + (x86_64_v2.imm8(_imm) ? 2 : 0) );
+        enc.add1( x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, 7, dst) );
+        // immediate(4 bytes) 32 bits or (1 byte)8 bits
+        if( x86_64_v2.imm8(_imm) ) enc.add1(_imm);
+        else                       enc.add4(_imm);
     }
-
     @Override public void asm(CodeGen code, SB sb) {
         String dst = code.reg(this);
         if( dst!="flags" )  sb.p(dst).p(" = ");
         sb.p(code.reg(in(1)));
         if( _imm != 0 ) sb.p(", #").p(_imm);
     }
-
-    @Override public String op() { return _imm==0 ? "test" : "cmp"; }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpMemX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpMemX86.java
index f9ace702..489853eb 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpMemX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpMemX86.java
@@ -1,33 +1,78 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeFloat;
 
 public class CmpMemX86 extends MemOpX86 {
-    final boolean _invert;      // Op switched LHS, RHS
-    CmpMemX86( BoolNode bool, LoadNode ld , Node base, Node idx, int off, int scale, int imm, Node val, boolean invert ) {
+    final boolean _swap;      // Op switched LHS, RHS
+    CmpMemX86( BoolNode bool, LoadNode ld, Node base, Node idx, int off, int scale, int imm, Node val, boolean swap ) {
         super(bool,ld, base, idx, off, scale, imm, val );
-        _invert = invert;
+        _swap = swap;
+        assert !_swap || val() == null || bool.op()=="==" || bool.op()=="!="; // Cannot swap with immediate
     }
-
-    // Register mask allowed as a result.  0 for no register.
+    @Override public String op() { return ((val()==null && _imm==0) ? "test" : "cmp") + _sz; }
     @Override public RegMask outregmap() { return x86_64_v2.FLAGS_MASK; }
+    @Override public void encoding( Encoding enc ) {
+        // REX.W + 81 /7 id	CMP r/m64, imm32 | REX.W + 39 /r	CMP r/m64,r64
+        // CMP [mem], imm32
+
+        short ptr = enc.reg(ptr());
+        short idx = enc.reg(idx());
+        short src = enc.reg(val());
+
+        if(src == -1) {
+            assert !_swap;
+            int log = _declaredType.log_size();
+            x86_64_v2.rexF(-1, ptr, idx, log==3, enc);
+            switch(log) {
+            case 0: enc.add1(0x80); break;
+            case 1: enc.add1(0x66).add1(0x81); break;
+            case 2: enc.add1(0x81); break;
+            case 3: enc.add1(0x81); break;
+            }
+            x86_64_v2.indirectAdr(_scale, idx, ptr, _off,  7, enc);
+            switch(log) {
+            case 0: enc.add1(_imm); break;
+            case 1: enc.add2(_imm); break;
+            case 2: enc.add4(_imm); break;
+            case 3: enc.add8(_imm); break;
+            }
+        } else {
+            encVal(enc, _declaredType, ptr, idx, src, _off, _scale, _swap);
+        }
+    }
+
+    static void encVal(Encoding enc, Type decl, short ptr, short idx, short src, int off, int scale, boolean _swap) {
+        if(decl instanceof TypeFloat) {
+            src -= (short)x86_64_v2.XMM_OFFSET;
+            enc.add1(decl==TypeFloat.F32 ? 0xF3 : 0xF2).add1(0x0F).add1(0xC2);
+        } else {
+            int log = decl.log_size();
+            x86_64_v2.rexF(src, ptr, idx, log == 3, enc);
+            int swap = _swap ? 2 : 0;
+            switch(log) {
+            case 0: enc.add1(0x38+swap); break;
+            case 1: enc.add1(0x66).add1(0x39+swap); break;
+            case 2: enc.add1(0x39+swap); break;
+            case 3: enc.add1(0x39+swap); break;
+            }
+        }
+        x86_64_v2.indirectAdr(scale, idx, ptr, off, src, enc);
+    }
 
     // General form: "cmp  dst = src, [base + idx<<2 + 12]"
     @Override public void asm(CodeGen code, SB sb) {
         String dst = code.reg(this);
-        if( dst!="FLAGS" )  sb.p(dst).p(" = ");
-        if( _invert ) asm_address(code,sb).p(",");
+        if( dst!="flags" )  sb.p(dst).p(" = ");
+        if( _swap ) asm_address(code,sb).p(",");
         if( val()==null ) {
             if( _imm!=0 )  sb.p("#").p(_imm);
         } else {
             sb.p(code.reg(val()));
         }
-        if( !_invert ) asm_address(code,sb.p(", "));
+        if( !_swap ) asm_address(code,sb.p(", "));
     }
-
-    @Override public String op() { return ((val()==null && _imm==0) ? "test" : "cmp") + _sz; }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpX86.java
index 41ce33d2..06a36d99 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpX86.java
@@ -1,29 +1,26 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class CmpX86 extends MachConcreteNode implements MachNode {
-    CmpX86( Node cmp ) { super(cmp); }
-
-    @Override public RegMask regmap(int i) { assert i==1 || i==2; return x86_64_v2.RMASK; }
+    CmpX86( Node add ) { super(add); }
+    @Override public String op() { return "cmp"; }
+    @Override public RegMask regmap(int i) { return x86_64_v2.RMASK; }
     @Override public RegMask outregmap() { return x86_64_v2.FLAGS_MASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
+    @Override public void encoding( Encoding enc ) {
+        short dst = enc.reg(in(1));
+        short src = enc.reg(in(2));
 
-    // General form: "add  dst += src"
+        enc.add1(x86_64_v2.rex(dst, src, 0));
+        enc.add1(0x3B);
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, src));
+    }
     @Override public void asm(CodeGen code, SB sb) {
         String dst = code.reg(this);
-        if( dst!="FLAGS" )  sb.p(dst).p(" = ");
+        if( dst!="flags" )  sb.p(dst).p(" = ");
         sb.p(code.reg(in(1))).p(", ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "cmp"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/DivFX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/DivFX86.java
index f74b7348..9509a1f5 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/DivFX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/DivFX86.java
@@ -1,35 +1,34 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class DivFX86 extends MachConcreteNode implements MachNode {
     DivFX86( Node divf) { super(divf); }
-
-    // Register mask allowed on input i.
-    @Override public RegMask regmap(int i) { assert i==1 || i==2; return x86_64_v2.XMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() {  return x86_64_v2.XMASK; }
-    // Output is same register as input#1
+    @Override public String op() { return "divf"; }
+    @Override public RegMask regmap(int i) { return x86_64_v2.XMASK; }
+    @Override public RegMask outregmap() { return x86_64_v2.XMASK; }
     @Override public int twoAddress() { return 1; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        // F2 0F 5E /r DIVSD xmm1, xmm2/m64
+        short dst = (short)(enc.reg(this ) - x86_64_v2.XMM_OFFSET);
+        short src = (short)(enc.reg(in(2)) - x86_64_v2.XMM_OFFSET);
+
+        // Fopcode
+        enc.add1(0xF2);
+        // rex prefix must come next (REX.W is not set)
+        x86_64_v2.rexF(dst, src, 0, false, enc);
+
+        enc.add1(0x0F).add1(0x5E);
+
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, src));
     }
 
 
     // General form: "divf  dst /= src"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" / ").p(code.reg(in(2)));
-    }
-
-    @Override public String op() {
-        // 8 bytes = 64 bits
-        return "divf";
+        sb.p(code.reg(this)).p(" /= ").p(code.reg(in(2)));
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/DivX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/DivX86.java
index 54372629..87b8b0c3 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/DivX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/DivX86.java
@@ -1,35 +1,33 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class DivX86 extends MachConcreteNode implements MachNode {
     DivX86( Node div ) { super(div); }
-
-    // Register mask allowed on input i.
+    @Override public String op() { return "div"; }
     @Override public RegMask regmap(int i) {
         return (i==1) ? x86_64_v2.RAX_MASK : x86_64_v2.RMASK;
     }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return x86_64_v2.RAX_MASK; }
-
-    // DIV encodes a CQO which sign extends RAX into RDX, killing RDX.
     @Override public RegMask killmap() { return x86_64_v2.RDX_MASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        // REX.W + F7 /7	IDIV r/m64
+        short src = enc.reg(in(2));
+        // sign extend rax before 128/64 bits division
+        // sign extend rax to rdx:rax
+        enc.add1(x86_64_v2.REX_W);
+        enc.add1(0x99);
+        enc.add1(x86_64_v2.rex(0, src, 0));
+        // divide
+        enc.add1(0xF7); // opcode
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, 0x07, src));
     }
-
     // General form: "div  dst /= src"
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" / ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "div"; }
     @Override public String comment() { return "kill rdx"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FltX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FltX86.java
index 47f7149d..e3b20003 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FltX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FltX86.java
@@ -1,35 +1,47 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.ConstantNode;
-import com.seaofnodes.simple.node.MachNode;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
 
-public class FltX86 extends ConstantNode implements MachNode {
+public class FltX86 extends ConstantNode implements MachNode, RIPRelSize{
+    private byte _encSize;
     FltX86(ConstantNode con ) { super(con); }
-    @Override public String op() { return "fld"; }
-
-    // Register mask allowed on input i.  0 for no register.
+    @Override public String op() { return "ld8"; }
     @Override public RegMask regmap(int i) { return null; }
-    // General int registers
     @Override public RegMask outregmap() { return x86_64_v2.XMASK; }
     @Override public boolean isClone() { return true; }
-    @Override public FltX86 copy() { return new FltX86(this); }
+    @Override public Node copy() { return new FltX86(this); }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        // Load the constant into a FPR
+        // movsd xmm, [rip + 0]
+        // F2 0F 10 /r MOVSD xmm1, m64
+        _encSize = 1/*Fop*/+0/*REX*/+2/*op*/+1/*MODRM*/+4/*offset*/;
+        short dst = (short)(enc.reg(this ) - x86_64_v2.XMM_OFFSET);
+        // Fopcode
+        enc.add1(0xF2);
+        // rex prefix must come next (REX.W is not set)
+        _encSize += x86_64_v2.rexF(dst, 0, 0, false, enc);
+        enc.add1(0x0F).add1(0x10);
+        // hard-code rip here
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.INDIRECT, dst, 0x05));
+        enc.add4(0);
+        enc.largeConstant(this,_con,_encSize-4,2/*ELF encoding PC32*/);
     }
 
-    // Human-readable form appended to the SB.  Things like the encoding,
-    // indentation, leading address or block labels not printed here.
-    // Just something like "ld4\tR17=[R18+12] // Load array base".
-    // General form: "op\tdst=src+src"
-    @Override public void asm(CodeGen code, SB sb) {
-        _con.print(sb.p(code.reg(this)).p(" #"));
+    // Delta is from opcode start
+    @Override public byte encSize(int delta) {
+        // TODO: 1-byte RIP offset?
+        return (byte)_encSize;
+    }
+
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        enc.patch4(opStart+opLen-4,delta-opLen);
     }
 
+    @Override public void asm(CodeGen code, SB sb) {
+        _con.print(sb.p(code.reg(this)).p(" = #"));
+    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FunX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FunX86.java
index 7346ae05..07418eb0 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FunX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FunX86.java
@@ -1,22 +1,34 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
+import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.node.FunNode;
 import com.seaofnodes.simple.node.MachNode;
-import java.io.ByteArrayOutputStream;
 
 public class FunX86 extends FunNode implements MachNode {
     FunX86( FunNode fun ) { super(fun); }
+    @Override public void postSelect(CodeGen code) {
+        super.postSelect(code);
+        // One more for RPC pre-pushed; X86 special
+        _maxArgSlot++;
+    }
 
-    // Register mask allowed on input i.  0 for no register.
-    @Override public RegMask regmap(int i) { return null; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return null; }
+    @Override public void computeFrameAdjust(CodeGen code, int maxReg) {
+        super.computeFrameAdjust(code,maxReg);
+        // Alignment, but off by RPC
+        if( _hasCalls )         // If non-leaf, pad to 16b
+            _frameAdjust = ((_frameAdjust+8+8) & -16)-8;
+    }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        return 0;
+    @Override public void encoding( Encoding enc ) {
+        int sz = _frameAdjust;
+        if( sz == 0 ) return; // Skip if no frame adjust
+        // opcode: 0x83, addi rsp with immediate 8
+        enc.add1( x86_64_v2.REX_W ).add1( x86_64_v2.imm8(sz) ? 0x83 : 0x81 );
+        enc.add1( x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, 0b101, x86_64_v2.RSP) );
+        if( x86_64_v2.imm8(sz) )  enc.add1(sz);
+        else                      enc.add4(sz);
     }
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/I2f8X86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/I2f8X86.java
index d99c92a8..d3213ae4 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/I2f8X86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/I2f8X86.java
@@ -1,30 +1,31 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class I2f8X86 extends MachConcreteNode implements MachNode {
     I2f8X86(Node i2f8 ) { super(i2f8); }
-
-    // Register mask allowed on input i.
+    @Override public String op() { return "cvtf"; }
     @Override public RegMask regmap(int i) { assert i==1; return x86_64_v2.WMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return x86_64_v2.XMASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
+    @Override public void encoding( Encoding enc ) {
+        // F2 0F 2A /r CVTSI2SD xmm1, r32/m32
+        short dst = (short)(enc.reg(this ) - x86_64_v2.XMM_OFFSET);
+        short src =         enc.reg(in(1));
+
+        // Fopcode
+        enc.add1(0xF2);
+        // rex prefix must come next (REX.W is not set)
+        x86_64_v2.rexF(dst, src, 0, true, enc);
 
-    // General form: "i2f8 (flt)int_value"
+        enc.add1(0x0F).add1(0x2A);
+
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, src));
+    }
 
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p("(flt)").p(code.reg(in(1)));
     }
-
-    @Override public String op() { return "i2f8"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ImmX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ImmX86.java
new file mode 100644
index 00000000..760d6805
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ImmX86.java
@@ -0,0 +1,37 @@
+package com.seaofnodes.simple.node.cpus.x86_64_v2;
+
+import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.TypeInteger;
+
+public abstract class ImmX86 extends MachConcreteNode implements MachNode {
+    final int _imm;
+    ImmX86( Node add, int imm ) {
+        super(add);
+        _inputs.pop();          // Pop constant input off
+        _imm = imm;
+    }
+    @Override public RegMask regmap(int i) { return x86_64_v2.RMASK; }
+    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
+    @Override public int twoAddress() { return 1; }
+
+    abstract int opcode();
+    abstract int mod();
+
+    @Override public final void encoding( Encoding enc ) {
+        short dst = enc.reg(this); // Also src1
+        enc.add1(x86_64_v2.rex(0, dst, 0));
+        // opcode; 0x81 or 0x83; 0x69 or 0x6B
+        enc.add1( opcode() + (x86_64_v2.imm8(_imm) ? 2 : 0) );
+        enc.add1( x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, mod(), dst) );
+        // immediate(4 bytes) 32 bits or (1 byte)8 bits
+        if( x86_64_v2.imm8(_imm) ) enc.add1(_imm);
+        else                       enc.add4(_imm);
+    }
+
+    // General form: "addi  dst += #imm"
+    @Override public void asm(CodeGen code, SB sb) {
+        sb.p(code.reg(this)).p(" ").p(glabel()).p("= #").p(_imm);
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/IntX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/IntX86.java
index fcd39e3f..6d9110f2 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/IntX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/IntX86.java
@@ -1,40 +1,65 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.ConstantNode;
-import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.node.Node;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeInteger;
 
-import java.io.ByteArrayOutputStream;
-
 // Integer constants
 public class IntX86 extends ConstantNode implements MachNode {
     IntX86( ConstantNode con ) { super(con); }
-
     @Override public String op() {
         return _con == Type.NIL || _con == TypeInteger.ZERO ? "xor" : "ldi";
     }
-
-    // Register mask allowed on input i.  0 for no register.
+    @Override public boolean isClone() { return true; }
+    @Override public Node copy() { return new IntX86(this); }
     @Override public RegMask regmap(int i) { return null; }
-    // General int registers
     @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-
     // Zero-set uses XOR kills flags
     @Override public RegMask killmap() {
         return _con == Type.NIL || _con == TypeInteger.ZERO ? x86_64_v2.FLAGS_MASK : null;
     }
 
-    @Override public boolean isClone() { return true; }
-    @Override public Node copy() { return new IntX86(this); }
+    @Override public void encoding( Encoding enc ) {
+        short dst = enc.reg(this);
+        // Short form for zero
+        if( _con==Type.NIL || _con==TypeInteger.ZERO ) {
+            // XOR dst,dst.  Can skip REX is dst is low 8, makes this a 32b
+            // xor, which will also zero the high bits.
+            if( dst >= 8 ) enc.add1(x86_64_v2.rex(dst, dst, 0));
+            enc.add1(0x33); // opcode
+            enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, dst));
+            return;
+        }
+
+        // Simply move the constant into a GPR
+        // Conditional encoding based on 64 or 32 bits
+        //REX.W + C7 /0 id	MOV r/m64, imm32
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+        long imm = ((TypeInteger)_con).value();
+        if (Integer.MIN_VALUE <= imm && imm < 0) {
+            // We need sign extension, so use imm32 into 64 bit register
+            // REX.W + C7 /0 id    MOV r/m64, imm32
+            enc.add1(x86_64_v2.rex(0, dst, 0));
+            enc.add1(0xC7); // 32 bits encoding
+            enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, 0x00, dst));
+            enc.add4((int)imm);
+        } else if (0 <= imm && imm <= 0xFFFFFFFFL) {
+            // We want zero extension into 64 bit register
+            // so move 32 bit into 32 bit register which zeros
+            // the upper bits in the 64 bit register.
+            // B8+ rd id     MOV r32, imm32
+            if (dst >= 8) enc.add1(0x41);
+            enc.add1(0xB8 + (dst & 0x07));
+            enc.add4((int)imm);
+        } else {
+            // Just write the full 64 bit constant
+            // REX.W + B8+ rd io     MOV r64, imm64
+            enc.add1(x86_64_v2.rex(0, dst, 0));
+            enc.add1(0xB8 + (dst & 0x07));
+            enc.add8(imm);               // 64 bits encoding
+        }
     }
 
     // Human-readable form appended to the SB.  Things like the encoding,
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/JmpX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/JmpX86.java
index 173f9ee7..d7acf8b8 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/JmpX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/JmpX86.java
@@ -1,48 +1,80 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 // Jump on flags, uses flags
-public class JmpX86 extends IfNode implements MachNode {
-    final String _bop;
+public class JmpX86 extends IfNode implements MachNode, RIPRelSize {
+    String _bop;
     JmpX86( IfNode iff, String bop ) {
         super(iff);
         _bop = bop;
     }
-
+    @Override public String op() { return "j"+_bop; }
     @Override public String label() { return op(); }
-
-    @Override public void postSelect() {
+    @Override public void postSelect(CodeGen code) {
         Node set = in(1);
+        if( set==null ) return; // Never-node cutout
         Node cmp = set.in(1);
         // Bypass an expected Set and just reference the cmp directly
-        if( set instanceof SetX86 && (cmp instanceof CmpX86 || cmp instanceof CmpIX86 || cmp instanceof CmpMemX86 || cmp instanceof CmpFX86) )
-            _inputs.set(1,cmp);
-        else
+        if( set instanceof SetX86 setx && (cmp instanceof CmpX86 || cmp instanceof CmpIX86 || cmp instanceof CmpMemX86 || cmp instanceof CmpFX86) ) {
+            _inputs.set( 1, cmp );
+            _bop = setx._bop;
+        } else
             throw Utils.TODO();
     }
     @Override public RegMask regmap(int i) { assert i==1; return x86_64_v2.FLAGS_MASK; }
     @Override public RegMask outregmap() { return null; }
+    @Override public void negate() { _bop = negate(_bop);  }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        if( in(1)!=null ) {
+            int op = x86_64_v2.jumpop(_bop);
+            enc.add1(op-16).add1(0); // Short form jump
+        } else {
+            if( _bop=="!=" ) return; // Inverted, no code
+            enc.add1(0xEB).add1(0);  // Never-node
+        }
+        enc.jump(this,cproj(0));
     }
 
-    @Override public void asm(CodeGen code, SB sb) {
-        String src = code.reg(in(1));
-        if( src!="flags" )  sb.p(src);
+    // Delta is from opcode start, but X86 measures from the end of the 2-byte encoding
+    @Override public byte encSize(int delta) {
+        if( in(1)==null && _bop=="!=" ) return 0; // Inverted never-node, no code
+        return (byte)(x86_64_v2.imm8(delta-2) ? 2 : 6);
     }
 
-    @Override public String op() { return "j"+_bop; }
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        assert !( in(1)==null && _bop=="!=" ); // Inverted never-node, no code no patch
+        byte[] bits = enc.bits();
+        if( opLen==2 ) {
+            assert in(1)==null || bits[opStart] == x86_64_v2.jumpop(_bop)-16;
+            delta -= 2;         // Offset from opcode END
+            assert (byte)delta==delta;
+            bits[opStart+1] = (byte)delta;
+        } else {
+            assert in(1)==null || bits[opStart] == x86_64_v2.jumpop(_bop)-16;
+            delta -= 6;         // Offset from opcode END
+            bits[opStart] = 0x0F;
+            bits[opStart+1] = (byte)(in(1)==null ? 0xE9 : x86_64_v2.jumpop(_bop));
+            enc.patch4(opStart+2,delta);
+        }
+    }
 
-    @Override public String comment() {
-        return "L"+cproj(1)._nid+", L"+cproj(0)._nid;
+    @Override public void asm(CodeGen code, SB sb) {
+        if( in(1)!=null ) {     // Never-node
+            String src = code.reg(in(1));
+            if( src!="flags" ) sb.p(src).p(" ");
+        } else if( _bop=="!=" ) {
+            sb.p("never");
+            return;
+        }
+        CFGNode prj = cproj(0).uctrlSkipEmpty(); // 0 is True is jump target
+        if( !prj.blockHead() ) prj = prj.cfg0();
+        sb.p(label(prj));
     }
+
+    @Override public String comment() { return "L"+cproj(1)._nid; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/LeaX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/LeaX86.java
index 229c0151..dce8a49a 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/LeaX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/LeaX86.java
@@ -1,18 +1,15 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class LeaX86 extends MachConcreteNode implements MachNode {
     final int _scale;
-    final long _offset;
-    LeaX86( Node add, Node base, Node idx, int scale, long offset ) {
+    final int _offset;
+    LeaX86( Node add, Node base, Node idx, int scale, int offset ) {
         super(add);
-        assert scale==1 || scale==2 || scale==4 || scale==8;
+        assert scale==0 || scale==1 || scale==2 || scale==3;
         _inputs.pop();
         _inputs.pop();
         _inputs.push(base);
@@ -21,14 +18,30 @@ public class LeaX86 extends MachConcreteNode implements MachNode {
         _offset = offset;
     }
 
-    // Register mask allowed on input i.
+    @Override public String op() { return "lea"; }
     @Override public RegMask regmap(int i) { assert i==1 || i==2; return x86_64_v2.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        // REX.W + 8D /r	LEA r64,m
+        short dst = enc.reg(this);
+        short ptr = enc.reg(in(1));
+        short idx = enc.reg(in(2));
+        // ptr is null
+        // just do: [(index * s) + disp32]
+        if( ptr == -1 ) {
+            enc.add1(x86_64_v2.rex(dst, 0, idx));
+            enc.add1(0x8D); // opcode
+            enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.INDIRECT, dst, 0x04));
+            enc.add1(x86_64_v2.sib(_scale, idx, x86_64_v2.RBP));
+            enc.add4(_offset);
+            return;
+        }
+
+        enc.add1(x86_64_v2.rex(dst, ptr, idx));
+        enc.add1(0x8D); // opcode
+        // rsp is hard-coded here(0x04)
+        x86_64_v2.indirectAdr(_scale, idx, ptr, _offset, dst, enc);
     }
 
     // General form: "lea  dst = base + 4*idx + 12"
@@ -36,9 +49,7 @@ public class LeaX86 extends MachConcreteNode implements MachNode {
         sb.p(code.reg(this)).p(" = ");
         if( in(1) != null )
             sb.p(code.reg(in(1))).p(" + ");
-        sb.p(code.reg(in(2))).p("*").p(_scale);
+        sb.p(code.reg(in(2))).p("<<").p(_scale);
         if( _offset!=0 ) sb.p(" + #").p(_offset);
     }
-
-    @Override public String op() { return "lea"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/LoadX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/LoadX86.java
index 893772a6..6e72a540 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/LoadX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/LoadX86.java
@@ -1,20 +1,55 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.LoadNode;
 import com.seaofnodes.simple.node.Node;
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeFloat;
+import com.seaofnodes.simple.type.TypeInteger;
+import com.seaofnodes.simple.type.TypeMemPtr;
 
 public class LoadX86 extends MemOpX86 {
     LoadX86( LoadNode ld, Node base, Node idx, int off, int scale ) {
         super(ld,ld, base, idx, off, scale, 0);
     }
-
     @Override public String op() { return "ld"+_sz; }
-
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return x86_64_v2.MEM_MASK; }
+    @Override public void encoding( Encoding enc ) {
+        // REX.W + 8B /r	MOV r64, r/m64
+        // Zero extension for u8, u16 and u32 but sign extension i8, i16, i32
+        // Use movsx and movzx
+        short dst = enc.reg(this );
+        short ptr = enc.reg(ptr());
+        short idx = enc.reg(idx());
+        enc(enc, _declaredType, dst, ptr, idx, _off, _scale);
+    }
+
+    static void enc( Encoding enc, Type decl, short dst, short ptr, short idx, int off, int scale ) {
+        if( decl == TypeFloat.F32) enc.add1(0xF3);
+        if( decl == TypeFloat.F64) enc.add1(0xF2);
+
+        if( decl.isa(TypeFloat.F64) )
+            dst -= (short)x86_64_v2.XMM_OFFSET;
+
+        x86_64_v2.rexF(dst, ptr, idx, decl != TypeInteger.U32 && decl != TypeFloat.F32 && decl != TypeFloat.F64, enc);
+
+        if( false ) ;
+        else if( decl == TypeFloat.F32   ) enc.add1(0x0F).add1(0x10); // F3 0F 10 /r MOVSS xmm1, m32
+        else if( decl == TypeFloat.F64   ) enc.add1(0x0F).add1(0x10); // F2 0F 10 /r MOVSD xmm1, m64
+        else if( decl.isa(TypeInteger.I8)) enc.add1(0x0F).add1(0xBE); // sign extend: REX.W + 0F BE /r MOVSX r64, r/m8
+        else if( decl == TypeInteger.I16 ) enc.add1(0x0F).add1(0xBF); // sign extend: REX.W + 0F BF /r MOVSX r64, r/m16
+        else if( decl == TypeInteger.I32 ) enc.add1(0x63);            // sign extend: REX.W + 63 /r    MOVSXD r64, r/m32
+        else if( decl == TypeInteger.U8  ) enc.add1(0x0F).add1(0xB6); // zero extend: REX.W + 0F B6 /r MOVZX r64, r/m8
+        else if( decl == TypeInteger.U16 ) enc.add1(0x0F).add1(0xB7); // zero extend: REX.W + 0F B7 /r MOVZX r64, r/m16
+        // Covers U32, I64/BOT, TMP
+        else if( decl.log_size()>=2 )     enc.add1(0x8B);            // zero extend:         8B /r    MOV r32, r/m32
+        else throw Utils.TODO();
+
+        // includes modrm internally
+        x86_64_v2.indirectAdr(scale, idx, ptr, off, dst, enc);
+    }
 
 
     // General form: "ldN  dst,[base + idx<<2 + 12]"
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MemAddX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MemAddX86.java
index 6d39a2b4..a97f3d9f 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MemAddX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MemAddX86.java
@@ -1,19 +1,34 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 
 public class MemAddX86 extends MemOpX86 {
     MemAddX86( StoreNode st, Node base, Node idx, int off, int scale, int imm, Node val ) {
         super(st, st, base, idx, off, scale, imm, val );
     }
-
+    @Override public String op() {
+        return (_imm == 1 ? "inc" : (_imm == -1 ? "dec" : "add")) + _sz;
+    }
     // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return null; }
+    @Override public void encoding( Encoding enc ) {
+        // add something to memory
+        // REX.W + 01 /r | REX.W + 81 /0 id
+        // ADD [mem], imm32/reg
+        short ptr = enc.reg(ptr());
+        short idx = enc.reg(idx());
+        short src = enc.reg(val());
 
+        enc.add1(x86_64_v2.rex(src, ptr, idx));
+        // opcode
+        enc.add1( src == -1 ? 0x81: 0x01);
 
+        // includes modrm
+        x86_64_v2.indirectAdr(_scale, idx, ptr, _off, src == -1 ? 0 : src, enc);
+        if( src == -1 ) enc.add4(_imm);
+    }
     // General form: "add  [base + idx<<2 + 12] += src"
     @Override public void asm(CodeGen code, SB sb) {
         asm_address(code,sb);
@@ -21,8 +36,4 @@ public class MemAddX86 extends MemOpX86 {
             if( _imm != 1 && _imm != -1 ) sb.p(" += #").p(_imm);
         } else sb.p(" += ").p(code.reg(val()));
     }
-
-    @Override public String op() {
-        return (_imm == 1 ? "inc" : (_imm == -1 ? "dec" : "add")) + _sz;
-    }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MemOpX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MemOpX86.java
index dee4afd4..97586d87 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MemOpX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MemOpX86.java
@@ -1,11 +1,10 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.*;
-import java.io.ByteArrayOutputStream;
+
 import java.lang.StringBuilder;
 import java.util.BitSet;
 
@@ -15,7 +14,7 @@ import java.util.BitSet;
 //   mem      - memory dependence edge
 //   base     - Basic object pointer
 //   idx/null - Scaled index offset, or null if none
-//   val/null - Value to store, as part of a op-to-mem or op-from-mem.  Null for loads, or if an immediate is being used
+//   val/null - Value to store, as part of an op-to-mem or op-from-mem.  Null for loads, or if an immediate is being used
 // Constants:
 //   offset   - offset added to base.  Can be zero.
 //   scale    - scale on index; only 0,1,2,4,8 allowed, 0 is only when index is null
@@ -24,13 +23,13 @@ public abstract class MemOpX86 extends MemOpNode implements MachNode {
     final int _off;             // Limit 32 bits
     final int _scale;           // Limit 0,1,2,3
     final int _imm;             // Limit 32 bits
-    final char _sz = (char)('0'+(1<<_declaredType.log_size()));
+    final char _sz;             // Handy print name
     MemOpX86( Node op, MemOpNode mop, Node base, Node idx, int off, int scale, int imm ) {
         super(op,mop);
         assert base._type instanceof TypeMemPtr && !(base instanceof AddNode);
         assert (idx==null && scale==0) || (idx!=null && 0<= scale && scale<=3);
 
-        // Copy memory parts from eg the LoadNode over the opcode, e.g. an Add
+        // Copy memory parts from e.g. the LoadNode over the opcode, e.g. an Add
         if( op != mop ) {
             _inputs.set(0,mop.in(0)); // Control from mem op
             _inputs.set(1,mop.in(1)); // Memory  from mem op
@@ -42,6 +41,7 @@ public abstract class MemOpX86 extends MemOpNode implements MachNode {
         _off = off;
         _scale = scale;
         _imm = imm;
+        _sz = (char)('0'+(1<<_declaredType.log_size()));
     }
 
     // Store-based flavors have a value edge
@@ -66,20 +66,19 @@ public abstract class MemOpX86 extends MemOpNode implements MachNode {
         if( i==1 ) return null;               // Memory
         if( i==2 ) return x86_64_v2.RMASK;    // base  in GPR
         if( i==3 ) return x86_64_v2.RMASK;    // index in GPR
-        if( i==4 ) return x86_64_v2.MEM_MASK; // value in GPR or XMM
-        throw Utils.TODO();
+        if( i==4 ) return _sz >= 2
+                       ? x86_64_v2.MEM_MASK   // value in GPR or XMM
+                       : x86_64_v2.RMASK;     // Bytes and shorts in GPR only
+        return null; // Anti-dependence
     }
 
-    @Override public int encoding(ByteArrayOutputStream bytes) { throw Utils.TODO(); }
-
-
     // "[base + idx<<2 + 12]"
     SB asm_address(CodeGen code, SB sb) {
         sb.p("[").p(code.reg(ptr()));
         if( idx() != null ) {
             sb.p("+").p(code.reg(idx()));
             if( _scale != 0 )
-                sb.p("<<").p(_scale);
+                sb.p("*").p((1<<_scale));
         }
         if( _off != 0 )
             sb.p("+").p(_off);
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulFX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulFX86.java
index 9e996130..c1edb082 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulFX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulFX86.java
@@ -1,34 +1,32 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeFloat;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class MulFX86 extends MachConcreteNode implements MachNode {
     MulFX86( Node mulf) { super(mulf); }
-
-    // Register mask allowed on input i.
+    @Override public String op() { return "mulf"; }
     @Override public RegMask regmap(int i) { assert i==1 || i==2; return x86_64_v2.XMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return x86_64_v2.XMASK; }
-    // Output is same register as input#1
     @Override public int twoAddress() { return 1; }
-    // Ok to swap arguments
     @Override public boolean commutes() { return true; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        // F2 0F 59 /r MULSD xmm1,xmm2/m64
+        short dst = (short)(enc.reg(this ) - x86_64_v2.XMM_OFFSET);
+        short src = (short)(enc.reg(in(2)) - x86_64_v2.XMM_OFFSET);
+
+        // Fopcode
+        enc.add1(0xF2);
+        // rex prefix must come next (REX.W is not set)
+        x86_64_v2.rexF(dst, src, 0, false, enc);
+
+        enc.add1(0x0F).add1(0x59).add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, src));
     }
 
     // General form: "mulf  dst *= src"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" * ").p(code.reg(in(2)));
+        sb.p(code.reg(this)).p(" *= ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "mulf"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulIX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulIX86.java
index b41a5720..a9a83fb7 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulIX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulIX86.java
@@ -1,41 +1,11 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.MachConcreteNode;
-import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.node.Node;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-
-public class MulIX86 extends MachConcreteNode  implements MachNode {
-    final TypeInteger _ti;
-    MulIX86(Node mul, TypeInteger ti) {super(mul); _inputs.pop(); _ti = ti;}
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        // assert i==1;
-        return x86_64_v2.WMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-    // General form
-    // General form: "muli  dst * #imm"
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" * #");
-        _ti.print(sb);
-    }
 
+public class MulIX86 extends ImmX86 {
+    MulIX86( Node add, int imm ) { super(add,imm); }
     @Override public String op() { return "muli"; }
+    @Override public String glabel() { return "*"; }
+    @Override int opcode() { return 0x69; }
+    @Override int mod() { return 0; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulX86.java
index d880208e..3cd1f795 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/MulX86.java
@@ -1,33 +1,29 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 public class MulX86 extends MachConcreteNode implements MachNode {
     MulX86( Node mul ) { super(mul); }
-
-    // Register mask allowed on input i.
+    @Override public String op() { return "mul"; }
     @Override public RegMask regmap(int i) { assert i==1 || i==2; return x86_64_v2.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-    // Output is same register as input#1
     @Override public int twoAddress() { return 1; }
-    // Ok to swap arguments
     @Override public boolean commutes() { return true; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        // REX.W + 0F AF /r	IMUL r64, r/m64
+        short dst = enc.reg(this ); // src1
+        short src = enc.reg(in(2)); // src2
+        enc.add1(x86_64_v2.rex(dst, src, 0));
+        enc.add1(0x0F); // opcode
+        enc.add1(0xAF); // opcode
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, src));
     }
 
     // General form: "mul  dst *= src"
     @Override public void asm(CodeGen code, SB sb) {
         sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" * ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "mul"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NegX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NegX86.java
new file mode 100644
index 00000000..b8b83cb0
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NegX86.java
@@ -0,0 +1,21 @@
+package com.seaofnodes.simple.node.cpus.x86_64_v2;
+
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
+
+public class NegX86 extends MachConcreteNode implements MachNode {
+    NegX86(MinusNode not) { super(not); }
+    @Override public String op() { return "neg"; }
+    @Override public RegMask regmap(int i) { return x86_64_v2.RMASK; }
+    @Override public RegMask outregmap()   { return x86_64_v2.RMASK; }
+    @Override public RegMask killmap()     { return x86_64_v2.FLAGS_MASK; }
+
+    @Override public void encoding( Encoding enc ) {
+        short dst = enc.reg(this );
+        enc.add1(x86_64_v2.rex(0, dst, 0));
+        enc.add1(0xF7); // opcode
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, 3, dst));
+    }
+    @Override public void asm(CodeGen code, SB sb) { sb.p(code.reg(this)); }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NewX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NewX86.java
index cd47c64b..0439adfd 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NewX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NewX86.java
@@ -1,29 +1,25 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.type.TypeFunPtr;
 
 public class NewX86 extends NewNode implements MachNode {
     // A pre-zeroed chunk of memory.
     NewX86( NewNode nnn ) { super(nnn); }
-    // Size and pointer result in standard calling convention; null for all the
-    // memory aliases edges
-    @Override public RegMask    regmap(int i) { return i == 1 ? x86_64_v2.RDI_MASK : null; }
-    @Override public RegMask outregmap(int i) { return i == 1 ? x86_64_v2.RAX_MASK : null; }
-    @Override public RegMask outregmap() { return null; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        enc.external(this,"calloc");
+        // ldi rcx,#1 // number of elements to calloc
+        enc.add1(0xB8 + _arg2Reg).add4(1);
+        // E8 cd    CALL rel32;
+        enc.add1(0xE8);
+        enc.add4(0);            // offset
     }
-
-    // General form: "alloc #bytes"
+    // General form: "alloc #bytes  PC"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(size()));
+        sb.p("ldi   rcx = #1\n");
+        sb.p("call  #calloc");
     }
 
-    @Override public String op() { return "alloc"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NotX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NotX86.java
index a4b82de8..b23249b8 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NotX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/NotX86.java
@@ -1,26 +1,39 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.LRG;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import java.io.ByteArrayOutputStream;
 
 public class NotX86 extends MachConcreteNode implements MachNode {
-    NotX86(NotNode not)  {super(not);}
+    NotX86(NotNode not) { super(not); }
+    @Override public String op() { return "not"; }
     @Override public RegMask regmap(int i) { return x86_64_v2.RMASK; }
     @Override public RegMask outregmap() { return x86_64_v2.RMASK;  }
+    @Override public RegMask killmap() { return x86_64_v2.FLAGS_MASK; }
+
+    @Override public void encoding( Encoding enc ) {
+        assert !(in(1) instanceof  NotNode); // Cleared out by peeps
+        assert !(in(1) instanceof BoolNode); // Cleared out by peeps
+        short dst = enc.reg(this );
+        short src = enc.reg(in(1));
 
-    @Override public int twoAddress( ) { return 0; }
+        // Pre-zero using XOR dst,dst; since zero'd will not have a
+        // byte-dependency from the setz.  Can skip REX is dst is low 8, makes
+        // this a 32b xor, which will also zero the high bits.
+        if( dst >= 8 ) enc.add1(x86_64_v2.rex(dst, dst, 0));
+        enc.add1(0x33); // opcode
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, dst));
 
-    // NotNode(BoolNode) = Inverted BoolNode(1)
-    // NotNode(NotNode(BoolNode)) = BoolNode(2)
-    // anything else to test & setz(3)
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+        // test   rdi,rdi
+        enc.add1(x86_64_v2.rex(src, src, 0));
+        enc.add1(0x85);
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, src, src));
+
+        // setz (sete dil)
+        enc.add1(x86_64_v2.rex(dst, 0, 0));
+        enc.add1(0x0F);
+        enc.add1(0x94);
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, 0));
     }
     @Override public void asm(CodeGen code, SB sb) { sb.p(code.reg(this)); }
-    @Override public String op() { return "not"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/OrIX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/OrIX86.java
index 949ac6c2..15f4824d 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/OrIX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/OrIX86.java
@@ -1,43 +1,11 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.MachConcreteNode;
-import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.node.Node;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-
-public class OrIX86  extends MachConcreteNode implements MachNode {
-
-    final TypeInteger _ti;
-    OrIX86(Node or, TypeInteger ti) {super(or);  _inputs.pop(); _ti = ti;}
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        //assert i==1;
-        return x86_64_v2.WMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form: "ori  ori | #imm"
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" | #");
-        _ti.print(sb);
-    }
 
+public class OrIX86 extends ImmX86 {
+    OrIX86( Node add, int imm ) { super(add,imm); }
     @Override public String op() { return "ori"; }
+    @Override public String glabel() { return "|"; }
+    @Override int opcode() { return 0x81; }
+    @Override int mod() { return 1; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/OrX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/OrX86.java
index 6d99fe3b..bc8f0ea8 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/OrX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/OrX86.java
@@ -1,35 +1,11 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.*;
-import java.io.ByteArrayOutputStream;
-
-public class OrX86 extends MachConcreteNode implements MachNode{
-    OrX86(Node or) {
-        super(or);
-    }
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) { assert i==1; return x86_64_v2.WMASK; }
-
-    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form: "or  dst | src"
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1)));
-    }
+import com.seaofnodes.simple.node.Node;
 
+public class OrX86 extends RegX86 {
+    OrX86( Node add ) { super(add); }
     @Override public String op() { return "or"; }
+    @Override public String glabel() { return "|"; }
+    @Override int opcode() { return 0x0B; }
+    @Override public boolean commutes() { return true; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ParmX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ParmX86.java
index 69ebb74e..5cfdd804 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ParmX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ParmX86.java
@@ -1,27 +1,17 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.node.ParmNode;
-import java.io.ByteArrayOutputStream;
 
 public class ParmX86 extends ParmNode implements MachNode {
     final RegMask _rmask;
     ParmX86( ParmNode parm ) {
         super(parm);
-        _rmask = x86_64_v2.callInMask(fun().sig(),_idx);
+        _rmask = x86_64_v2.callInMask(fun().sig(),_idx,1/*RPC*/);
     }
-
-    // Register mask allowed on input i.  0 for no register.
-    @Override public RegMask regmap(int i) { return _rmask; }
-    // Register mask allowed as a result.  Calling convention register
+    @Override public RegMask regmap(int i) { return null; }
     @Override public RegMask outregmap() { return _rmask; }
-
-    // Encoding is appended into the byte array.  Returns size
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        return 0;
-    }
+    @Override public void encoding( Encoding enc ) { }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ProjX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ProjX86.java
index 7ac014e6..046c7b4c 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ProjX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ProjX86.java
@@ -1,23 +1,15 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.codegen.RegMask;
 import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.node.ProjNode;
-import java.io.ByteArrayOutputStream;
 
 public class ProjX86 extends ProjNode implements MachNode {
     ProjX86( ProjNode p ) { super(p); }
-
-    // Register mask allowed on input i.  0 for no register.
     @Override public RegMask regmap(int i) { return null; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() {
         return ((MachNode)in(0)).outregmap(_idx);
     }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        return 0;
-    }
+    @Override public void encoding( Encoding enc ) {}
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/RegX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/RegX86.java
new file mode 100644
index 00000000..0997644d
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/RegX86.java
@@ -0,0 +1,26 @@
+package com.seaofnodes.simple.node.cpus.x86_64_v2;
+
+import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
+
+public abstract class RegX86 extends MachConcreteNode {
+    RegX86( Node add ) { super(add); }
+    @Override public RegMask regmap(int i) { return x86_64_v2.RMASK; }
+    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
+    @Override public int twoAddress() { return 1; }
+    abstract int opcode();
+    @Override public void encoding( Encoding enc ) {
+        // REX.W + 01 /r
+        short dst = enc.reg(in(1)); // src1
+        short src = enc.reg(in(2)); // src2
+
+        enc.add1(x86_64_v2.rex(dst, src, 0));
+        enc.add1(opcode()); // opcode
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, src));
+    }
+    // General form: "add  dst += src"
+    @Override public void asm(CodeGen code, SB sb) {
+        sb.p(code.reg(this)).p(" ").p(glabel()).p("= ").p(code.reg(in(2)));
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/RetX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/RetX86.java
index 433f64cc..a35d43a2 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/RetX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/RetX86.java
@@ -1,49 +1,19 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.FunNode;
-import com.seaofnodes.simple.node.ReturnNode;
-import com.seaofnodes.simple.node.MachNode;
-import com.seaofnodes.simple.type.TypeFloat;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
 
-// Return
 public class RetX86 extends ReturnNode implements MachNode {
     RetX86( ReturnNode ret, FunNode fun ) { super(ret, fun); fun.setRet(this); }
-
-    // Correct Nodes outside the normal edges
-    @Override public void postSelect() {
-        FunNode fun = (FunNode)rpc().in(0);
-        _fun = fun;
-        fun.setRet(this);
-    }
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) { return x86_64_v2.retMask(_fun.sig(),i); }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return null; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        // Without imm form
-        // Near return
-        int beforeSize = bytes.size();
-        bytes.write(0xC3); // opcode
-
-        return bytes.size() - beforeSize;
-    }
-
-    @Override public void asm(CodeGen code, SB sb) {
-        // Post code-gen, just print the "ret"
-        if( code._phase.ordinal() <= CodeGen.Phase.RegAlloc.ordinal() )
-            // Prints return reg (either RAX or XMM0), RPC (always [rsp-4]) and
-            // then the callee-save registers.
-            for( int i=2; i<nIns(); i++ )
-                sb.p(code.reg(in(i))).p("  ");
+    @Override public void encoding( Encoding enc ) {
+        int sz = fun()._frameAdjust;
+        if( sz != 0 ) {
+            enc.add1( x86_64_v2.REX_W ).add1( x86_64_v2.imm8(sz) ? 0x83 : 0x81 );
+            enc.add1( x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, 0b000, x86_64_v2.RSP) );
+            if( x86_64_v2.imm8(sz) )  enc.add1(sz);
+            else                      enc.add4(sz);
+        }
+        enc.add1(0xC3);
     }
-
-    @Override public String op() { return "ret"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SarIX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SarIX86.java
index 9f942cc6..07256604 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SarIX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SarIX86.java
@@ -1,39 +1,40 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.node.MachNode;
+import com.seaofnodes.simple.node.Node;
+
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
 // Arithmetic Right Shift
 public class SarIX86 extends MachConcreteNode implements MachNode {
-    final TypeInteger _ti;
-    SarIX86(Node sar, TypeInteger ti) {super(sar); _inputs.pop();  _ti = ti;}
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        // assert i==1;
-        return x86_64_v2.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
+    final int _imm;
+    SarIX86( Node sari, int imm ) { super(sari); assert x86_64_v2.imm8(imm); _inputs.pop(); _imm = imm; }
+    @Override public String op() { return "sari"; }
+    @Override public String glabel() { return ">>"; }
+    int opcode() { return 0xC1; }
+    int mod() { return 7; }
 
-    // Output is same register as input#1
+    @Override public RegMask regmap(int i) { return x86_64_v2.RMASK; }
+    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
     @Override public int twoAddress() { return 1; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding(Encoding enc) {
+        short dst = enc.reg(this); // Also src1
+        enc.add1(x86_64_v2.rex(0, dst, 0));
+        enc.add1( opcode());
+
+        enc.add1( x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, mod(), dst) );
+
+        // immediate(4 bytes) 32 bits or (1 byte)8 bits
+        if( x86_64_v2.imm8(_imm) ) enc.add1(_imm);
+        else                       enc.add4(_imm);
     }
 
-    // General form
-    // General form: "sari  dst << #imm"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" >> #");
-        _ti.print(sb);
+        sb.p(code.reg(this)).p(" ").p(glabel()).p("= #").p(_imm);
     }
-
-    @Override public String op() { return "sari"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SarX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SarX86.java
index ee7a2f56..b1be643c 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SarX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SarX86.java
@@ -1,41 +1,24 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
-import java.lang.StringBuilder;
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.Node;
 
-
-public class SarX86 extends MachConcreteNode implements MachNode {
-    SarX86(Node sar) { super(sar); }
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
+public class SarX86 extends RegX86 {
+    SarX86( Node add ) { super(add); }
+    @Override public String op() { return "sar"; }
+    @Override public String glabel() { return ">>"; }
     @Override public RegMask regmap(int i) {
-        if(i == 1) return x86_64_v2.WMASK;
-        if(i == 2) return x86_64_v2.RCX_MASK;
-        throw Utils.TODO();
-    }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
+        if (i == 1) return x86_64_v2.WMASK;
+        if (i == 2) return x86_64_v2.RCX_MASK;
         throw Utils.TODO();
     }
-
-    // General form
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" >> ").p(code.reg(in(1)));
+    @Override int opcode() { return 0xD3; }
+    @Override public void encoding( Encoding enc ) {
+        short dst = enc.reg(this ); // src1
+        short src = enc.reg(in(2)); // src2
+        enc.add1(x86_64_v2.rex(0, dst, 0));
+        enc.add1(opcode()); // opcode
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, 7, dst));
     }
-
-    @Override public String op() { return "sar"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SetX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SetX86.java
index 53237538..b2902086 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SetX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SetX86.java
@@ -1,33 +1,48 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
 
-// Compare immediate.  Sets flags.
 // Corresponds to the x86 instruction "sete && setne".
 // Use result of comparison without jump.
 public class SetX86 extends MachConcreteNode implements MachNode {
     final String _bop;          // One of <,<=,==
+    final boolean _unsigned;
     // Constructor expects input is an X86 and not an Ideal node.
-    SetX86( Node cmp, String bop ) {
+    SetX86( Node cmp, String bop, boolean unsigned ) {
         super(cmp);
         _inputs.setLen(1);   // Pop the cmp inputs
         // Replace with the matched cmp
         _inputs.push(cmp);
         _bop = bop;
+        _unsigned = unsigned;
     }
-
+    @Override public String op() { return "set"+_bop; }
     @Override public RegMask regmap(int i) { assert i==1; return x86_64_v2.FLAGS_MASK; }
     @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        // REX + 0F 94
+        short dst = enc.reg(this );
+
+        // Optional rex, for dst
+        if( dst >= 8 ) enc.add1(x86_64_v2.rex(0, dst, 0));
+        enc.add1(0x0F);         // opcode
+        enc.add1(switch (_bop) {
+            case "==" -> 0x94;  // SETE
+            case "<"  -> _unsigned ? 0x92 : 0x9C;  // SETB /SETL
+            case "<=" -> _unsigned ? 0x96 : 0x9E;  // SETBE/SETLE
+            case ">=" -> _unsigned ? 0x93 : 0x9D;  // SETAE/SETGE
+            default -> throw Utils.TODO();
+            });
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, 0, dst));
+
+        // low 8 bites are set, now zero extend for next instruction
+        if( dst >= 8 ) enc.add1(x86_64_v2.rex(0, dst, 0));
+        enc.add1(0x0F); // opcode
+        enc.add1(0xB6); // opcode
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, dst));
     }
 
     @Override public void asm(CodeGen code, SB sb) {
@@ -35,7 +50,4 @@ public class SetX86 extends MachConcreteNode implements MachNode {
         String src = code.reg(in(1));
         if( src!="flags" )  sb.p(" = ").p(src);
     }
-
-    @Override public String op() { return "set"+_bop; }
-
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShlIX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShlIX86.java
index c18007cd..0b75b456 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShlIX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShlIX86.java
@@ -1,40 +1,40 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
+import com.seaofnodes.simple.node.Node;
+
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
 
-public class ShlIX86 extends MachConcreteNode implements MachNode{
-    final TypeInteger _ti;
-    ShlIX86(Node shl, TypeInteger ti) {super(shl); _inputs.pop(); _ti = ti;}
+public class ShlIX86 extends MachConcreteNode implements MachNode {
+    final int _imm;
+    ShlIX86( Node shli, int imm ) {
+        super(shli);
+        assert x86_64_v2.imm8(imm);
+        _inputs.pop();          // Pop constant input off
+        _imm = imm;
+    }
+    public int opcode() { return 0xC1; }
+    public int mod() { return 4; }
 
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        //assert i==1;
-        return x86_64_v2.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
+    @Override public RegMask regmap(int i) { return x86_64_v2.RMASK; }
     @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-
-    // Output is same register as input#1
     @Override public int twoAddress() { return 1; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
+    @Override public String op() { return "shli"; }
+    @Override public String glabel() { return "<<"; }
+    @Override public void encoding(Encoding enc) {
+        short dst = enc.reg(this); // Also src1
+        enc.add1(x86_64_v2.rex(0, dst, 0));
+        enc.add1( opcode());
 
-    // General form
-    // General form: "shli  dst << #imm"
+        enc.add1( x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, mod(), dst) );
+
+        // immediate(4 bytes) 32 bits or (1 byte)8 bits
+        if( x86_64_v2.imm8(_imm) ) enc.add1(_imm);
+        else                       enc.add4(_imm);
+    }
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" << #");
-        _ti.print(sb);
+        sb.p(code.reg(this)).p(" ").p(glabel()).p("= #").p(_imm);
     }
-
-    @Override public String op() { return "shli"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShlX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShlX86.java
index a3de5347..9f358575 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShlX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShlX86.java
@@ -1,39 +1,24 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.*;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.Node;
 
-public class ShlX86 extends MachConcreteNode implements MachNode {
-    ShlX86(Node shl) { super(shl); };
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-
-    // CL register must be used for input(2)
+public class ShlX86 extends RegX86 {
+    ShlX86( Node add ) { super(add); }
+    @Override public String op() { return "shl"; }
+    @Override public String glabel() { return "<<"; }
     @Override public RegMask regmap(int i) {
-        if(i == 1) return x86_64_v2.WMASK;
-        if(i == 2) return x86_64_v2.RCX_MASK;
+        if (i == 1) return x86_64_v2.WMASK;
+        if (i == 2) return x86_64_v2.RCX_MASK;
         throw Utils.TODO();
     }
-
-    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form: "shl  dst << src"
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" << ").p(code.reg(in(1)));
+    @Override int opcode() { return 0xD3; }
+    @Override public final void encoding( Encoding enc ) {
+        short dst = enc.reg(this ); // src1
+        short src = enc.reg(in(2)); // src2
+        enc.add1(x86_64_v2.rex(0, dst, 0));
+        enc.add1(opcode()); // opcode
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, 4, dst));
     }
-
-    @Override public String op() { return "shl"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShrIX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShrIX86.java
index d17ee734..893eb23d 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShrIX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShrIX86.java
@@ -1,41 +1,35 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
+import com.seaofnodes.simple.node.Node;
+
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.Type;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-import java.util.BitSet;
-import java.lang.StringBuilder;
 
-public class ShrIX86 extends MachConcreteNode implements MachNode{
-    final TypeInteger _ti;
-    ShrIX86(Node shr, TypeInteger ti) {super(shr); _inputs.pop(); _ti = ti;}
+public class ShrIX86 extends MachConcreteNode implements MachNode {
+    final int _imm;
+    ShrIX86( Node shri, int imm ) { super(shri); assert x86_64_v2.imm8(imm); _inputs.pop(); _imm = imm; }
+    @Override public String op() { return "shri"; }
+    @Override public String glabel() { return ">>>"; }
+    int opcode() { return 0xC1; }
+    int mod() { return 5; }
 
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) {
-        //assert i==1;
-        return x86_64_v2.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
+    @Override public RegMask regmap(int i) { return x86_64_v2.RMASK; }
     @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-
-    // Output is same register as input#1
     @Override public int twoAddress() { return 1; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
+    @Override public void encoding(Encoding enc) {
+        short dst = enc.reg(this); // Also src1
+        enc.add1(x86_64_v2.rex(0, dst, 0));
+        enc.add1( opcode());
 
-    // General form
-    // General form: "shri  dst >>> #imm"
+        enc.add1( x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, mod(), dst) );
+
+        // immediate(4 bytes) 32 bits or (1 byte)8 bits
+        if( x86_64_v2.imm8(_imm) ) enc.add1(_imm);
+        else                       enc.add4(_imm);
+    }
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" >>> #");
-        _ti.print(sb);
+        sb.p(code.reg(this)).p(" ").p(glabel()).p("= #").p(_imm);
     }
-
-    @Override public String op() { return "shri"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShrX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShrX86.java
index 757d9b8e..d869260f 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShrX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/ShrX86.java
@@ -1,40 +1,24 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.*;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.Node;
 
-public class ShrX86 extends MachConcreteNode implements MachNode {
-    ShrX86(Node shr) {
-        super(shr);
-    };
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-
-    // CL register must be used for input(2)
+public class ShrX86 extends RegX86 {
+    ShrX86( Node add ) { super(add); }
+    @Override public String op() { return "shr"; }
+    @Override public String glabel() { return ">>>"; }
     @Override public RegMask regmap(int i) {
-        if(i == 1) return x86_64_v2.WMASK;
-        if(i == 2) return x86_64_v2.RCX_MASK;
-        throw Utils.TODO();
-    }
-
-    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
+        if (i == 1) return x86_64_v2.WMASK;
+        if (i == 2) return x86_64_v2.RCX_MASK;
         throw Utils.TODO();
     }
-
-    // General form
-    // General form: "shr  dst >>> src"
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" >>> ").p(code.reg(in(1)));
+    @Override int opcode() { return 0xD3; }
+    @Override public final void encoding( Encoding enc ) {
+        short dst = enc.reg(this ); // src1
+        short src = enc.reg(in(2)); // src2
+        enc.add1(x86_64_v2.rex(0, dst, 0));
+        enc.add1(opcode()); // opcode
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, 5, dst));
     }
-
-    @Override public String op() { return "shr"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SplitX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SplitX86.java
index ea283a87..960ea6f8 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SplitX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SplitX86.java
@@ -1,21 +1,107 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
+import com.seaofnodes.simple.SB;
 import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.FunNode;
 import com.seaofnodes.simple.node.Node;
 import com.seaofnodes.simple.node.SplitNode;
-import java.io.ByteArrayOutputStream;
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeFloat;
+import com.seaofnodes.simple.type.TypeInteger;
 
 public class SplitX86 extends SplitNode {
     SplitX86( String kind, byte round ) { super(kind,round, new Node[2]); }
-
-    // Register mask allowed on input i.
+    @Override public String op() { return "mov"; }
     @Override public RegMask regmap(int i) { return x86_64_v2.SPLIT_MASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return x86_64_v2.SPLIT_MASK; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    // Need to handle 8 cases: . reg->reg, reg->xmm, reg->flags, xmm->reg, xmm->xmm, xmm->flags, flags->reg, flags->xmm,
+    // flags->flags.
+    @Override public void encoding( Encoding enc ) {
+        // REX.W + 8B /r	MOV r64, r/m64
+        short dst = enc.reg(this );
+        short src = enc.reg(in(1));
+        if( dst == x86_64_v2.FLAGS ) {
+            // mov reg, flags
+            // push rcx
+            // popf (Pop the top of the stack into the FLAGS register)
+            // 50+rd	PUSH r64
+            x86_64_v2.rexF(0,src,0,false,enc);
+            enc.add1(0x50 + src);
+            // popf
+            enc.add1(0x9D);
+            return;
+        }
+        if( src == x86_64_v2.FLAGS ) {
+            // mov flags, reg
+            // pushf; pop reg
+            enc.add1(0x9C);
+            // 58+ rd	POP r64
+            x86_64_v2.rexF(0,dst,0,false, enc);
+            enc.add1(0x58 + dst);
+            return;
+        }
+
+        // Flag for being either XMM or stack
+        boolean dstX = dst >= x86_64_v2.XMM_OFFSET;
+        boolean srcX = src >= x86_64_v2.XMM_OFFSET;
+
+        // Stack spills
+        if( dst >= x86_64_v2.MAX_REG ) {
+            int off = enc._fun.computeStackOffset(enc._code,dst);
+            if( src >= x86_64_v2.MAX_REG ) {
+                // Rare stack-stack move.  push [RSP+soff]; pop [RSP+doff]
+                int soff = enc._fun.computeStackOffset(enc._code,src);
+                enc.add1(0xFF);
+                x86_64_v2.indirectAdr(0, (short)-1/*index*/, (short)x86_64_v2.RSP, soff, 6, enc);
+                enc.add1(0x8F);
+                x86_64_v2.indirectAdr(0, (short)-1/*index*/, (short)x86_64_v2.RSP,  off, 0, enc);
+                return;
+            }
+            StoreX86.encVal(enc, srcX ? TypeFloat.F64 : TypeInteger.BOT, (short)x86_64_v2.RSP, (short)-1/*index*/, src, off, 0);
+            return;
+        }
+        if( src >= x86_64_v2.MAX_REG ) {
+            int off = enc._fun.computeStackOffset(enc._code,src);
+            LoadX86.enc(enc, dstX ? TypeFloat.F64 : TypeInteger.BOT, dst, (short)x86_64_v2.RSP, (short)-1, off, 0);
+            return;
+        }
+
+        // reg-reg move.  Adjust numbering for GPR vs FPR reg set
+        if( dstX ) dst -= (short) x86_64_v2.XMM_OFFSET;
+        if( srcX ) src -= (short) x86_64_v2.XMM_OFFSET;
+
+        // 0x66 if moving between register classes
+        if( dstX ^ srcX )  enc.add1(0x66);
+        if( !dstX && srcX )
+            { short tmp=src; src=dst; dst=tmp; }
+        enc.add1(x86_64_v2.rex(dst, src, 0));
+
+        // pick opcode based on regs
+        if( !dstX && !srcX ) {
+            // reg->reg (MOV r64, r/m64)
+            enc.add1(0x8B);
+        } else if( dstX && srcX ) {
+            // xmm->xmm (NP 0F 28 /r MOVAPS xmm1, xmm2/m128)
+            enc.add1(0x0F);
+            enc.add1(0x28);
+        } else if( dstX && !srcX ) {
+            // reg->xmm (66 REX.W 0F 6E /r MOVQ xmm, r/m64)
+            enc.add1(0x0F);
+            enc.add1(0x6E);
+        } else if( !dstX && srcX ) {
+            // xmm->reg(66 0F 7E /r MOVQ r/m64, xmm)
+            enc.add1(0x0F);
+            enc.add1(0x7E);
+        }
+
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, src));
+    }
+
+    // General form: "mov  dst = src"
+    @Override public void asm(CodeGen code, SB sb) {
+        FunNode fun = code._encoding==null ? null : code._encoding._fun;
+        sb.p(code.reg(this,fun)).p(" = ").p(code.reg(in(1),fun));
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/StoreX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/StoreX86.java
index 024ef904..76fb4e8d 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/StoreX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/StoreX86.java
@@ -1,19 +1,19 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.ConstantNode;
 import com.seaofnodes.simple.node.Node;
 import com.seaofnodes.simple.node.StoreNode;
+import com.seaofnodes.simple.type.Type;
+import com.seaofnodes.simple.type.TypeFloat;
 import java.util.BitSet;
 
 public class StoreX86 extends MemOpX86 {
     StoreX86( StoreNode st, Node base, Node idx, int off, int scale, int imm, Node val ) {
         super(st,st, base, idx, off, scale, imm, val);
     }
-
     @Override public String op() { return "st"+_sz; }
-
     @Override public StringBuilder _printMach(StringBuilder sb, BitSet visited) {
         Node val = val();
         sb.append(".").append(_name).append("=");
@@ -21,9 +21,60 @@ public class StoreX86 extends MemOpX86 {
         else val._print0(sb,visited);
         return sb.append(";");
     }
-
     // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return null; }
+    @Override public void encoding( Encoding enc ) {
+        // REX.W + C7 /0 id	MOV r/m64, imm32 |
+        // REX.W + 89 /r        MOV r/m64, r64
+        short ptr = enc.reg(ptr());
+        short idx = enc.reg(idx());
+        short src = enc.reg(val());
+
+        if( src == -1 ) {
+            int log = _declaredType.log_size();
+            x86_64_v2.rexF(-1, ptr, idx, log==3, enc);
+            switch( log ) {
+            case 0: enc           .add1(0xC6); break;
+            case 1: enc.add1(0x66).add1(0xC7); break;
+            case 2: enc           .add1(0xC7); break;
+            case 3: enc           .add1(0xC7); break;
+            }
+            x86_64_v2.indirectAdr(_scale, idx, ptr, _off, src, enc);
+            switch( log ) {
+            case 0: enc.add1(_imm); break;
+            case 1: enc.add2(_imm); break;
+            case 2: enc.add4(_imm); break;
+            case 3: enc.add4(_imm); break; // Limit of a 4 byte immediate
+            }
+        } else {
+            encVal(enc,_declaredType,ptr,idx,src,_off,_scale);
+        }
+    }
+
+    // Non-immediate encoding
+    static void encVal( Encoding enc, Type decl, short ptr, short idx, short src, int off, int scale ) {
+        int log = decl.log_size();
+        // Float reg being stored
+        if( src >= x86_64_v2.XMM_OFFSET ) {
+            src -= (short)x86_64_v2.XMM_OFFSET;
+            assert log == 2 || log == 3;
+            enc.add1( log==2 ? 0xF3 : 0xF2 );
+            x86_64_v2.rexF(src,ptr,idx,false,enc);
+            enc.add1(0x0F).add1(0x11);
+        } else {
+            // byte stores from sil, dil, bpl, spl need a rex
+            if( log == 0 && src >= x86_64_v2.RSP ) enc.add1(x86_64_v2.rex(src,ptr,idx,false));
+            else x86_64_v2.rexF(src,ptr,idx,log==3,enc);
+            switch( log ) {
+            case 0: enc           .add1(0x88); break;
+            case 1: enc.add1(0x66).add1(0x89); break;
+            case 2: enc           .add1(0x89); break;
+            case 3: enc           .add1(0x89); break;
+            }
+        }
+        x86_64_v2.indirectAdr(scale, idx, ptr, off, src, enc);
+    }
+
 
     // General form: "stN  [base + idx<<2 + 12],val"
     @Override public void asm(CodeGen code, SB sb) {
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SubFX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SubFX86.java
index ceaf0636..0a169a22 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SubFX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SubFX86.java
@@ -1,31 +1,31 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
-import java.io.ByteArrayOutputStream;
 
 public class SubFX86 extends MachConcreteNode implements MachNode {
     SubFX86( Node subf) {  super(subf); }
-
-
-    // Register mask allowed on input i.
+    @Override public String op() { return "subf"; }
     @Override public RegMask regmap(int i) { assert i==1 || i==2; return x86_64_v2.XMASK; }
-    // Register mask allowed as a result.  0 for no register.
     @Override public RegMask outregmap() { return x86_64_v2.XMASK; }
-    // Output is same register as input#1
     @Override public int twoAddress() { return 1; }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    @Override public void encoding( Encoding enc ) {
+        // F2 0F 5C /r SUBSD xmm1, xmm2/m64
+        short dst = (short)(enc.reg(this ) - x86_64_v2.XMM_OFFSET);
+        short src = (short)(enc.reg(in(2)) - x86_64_v2.XMM_OFFSET);
+        // Fopcode
+        enc.add1(0xF2);
+        // rex prefix must come next (REX.W is not set)
+        x86_64_v2.rexF(dst, src, 0, false, enc);
+
+        enc.add1(0x0F).add1(0x5C);
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, src));
     }
 
     // General form: "subf  dst -= src"
     @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" - ").p(code.reg(in(2)));
+        sb.p(code.reg(this)).p(" -= ").p(code.reg(in(2)));
     }
-
-    @Override public String op() { return "subf"; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SubX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SubX86.java
index da44a838..8da34bf5 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SubX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SubX86.java
@@ -1,31 +1,10 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-
-public class SubX86 extends MachConcreteNode implements MachNode {
-    SubX86( Node sub ) { super(sub); }
-
-    // Register mask allowed on input i.
-    @Override public RegMask regmap(int i) { assert i==1 || i==2; return x86_64_v2.RMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form: "sub  dst -= src"
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" - ").p(code.reg(in(2)));
-    }
+import com.seaofnodes.simple.node.Node;
 
+public class SubX86 extends RegX86 {
+    SubX86( Node add ) { super(add); }
     @Override public String op() { return "sub"; }
+    @Override public String glabel() { return "-"; }
+    @Override int opcode() { return 0x2B; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/TFPX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/TFPX86.java
index 2b4de2ca..be4d1a83 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/TFPX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/TFPX86.java
@@ -1,29 +1,55 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.ConstantNode;
-import com.seaofnodes.simple.node.MachNode;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.node.cpus.riscv.riscv;
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeFunPtr;
 
-import java.io.ByteArrayOutputStream;
-
 // Function constants
-public class TFPX86 extends ConstantNode implements MachNode {
+public class TFPX86 extends ConstantNode implements MachNode, RIPRelSize {
     TFPX86( ConstantNode con ) {  super(con); }
-    @Override public String op() { return _con == Type.NIL ? "xor" : "ldx"; }
-    // Register mask allowed on input i.  0 for no register.
+    @Override public String op() {
+        return _con == Type.NIL ? "xor" : "ldx";
+    }
+    @Override public boolean isClone() { return true; }
+    @Override public Node copy() { return new TFPX86(this); }
     @Override public RegMask regmap(int i) { return null; }
-    // General int registers
     @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-    @Override public boolean isClone() { return true; }
-    @Override public TFPX86 copy() { return new TFPX86(this); }
+    // Zero-set uses XOR kills flags
+    @Override public RegMask killmap() {
+        return _con == Type.NIL ? x86_64_v2.FLAGS_MASK : null;
+    }
+
+    @Override public void encoding( Encoding enc ) {
+        short dst = enc.reg(this);
+        // Short form for zero
+        if( _con==Type.NIL ) {
+            // XOR dst,dst.  Can skip REX is dst is low 8, makes this a 32b
+            // xor, which will also zero the high bits.
+            if( dst >= 8 ) enc.add1(x86_64_v2.rex(dst, dst, 0));
+            enc.add1(0x33); // opcode
+            enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, dst, dst));
+            return;
+        }
+
+        // lea to load function pointer address
+        // lea rax, [rip+disp32]
+        enc.relo(this);
+        enc.add1(x86_64_v2.rex(dst, 0, 0));
+        enc.add1(0x8D); // opcode
+        enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.INDIRECT, dst, 0b101));
+        enc.add4(0);
+    }
+
+    @Override public byte encSize(int delta) {
+        return 7;
+    }
 
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        enc.patch4(opStart + 3, delta - 7);
     }
 
     // Human-readable form appended to the SB.  Things like the encoding,
@@ -35,6 +61,6 @@ public class TFPX86 extends ConstantNode implements MachNode {
         if( _con == Type.NIL )
             sb.p(reg).p(",").p(reg);
         else
-            _con.print(sb.p(reg).p(" #"));
+            _con.print(sb.p(reg).p(" = #"));
     }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/UJmpX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/UJmpX86.java
new file mode 100644
index 00000000..ec4eeb3b
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/UJmpX86.java
@@ -0,0 +1,53 @@
+package com.seaofnodes.simple.node.cpus.x86_64_v2;
+
+import com.seaofnodes.simple.*;
+import com.seaofnodes.simple.codegen.*;
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.type.Type;
+import java.util.BitSet;
+
+// unconditional jump
+public class UJmpX86 extends CFGNode implements MachNode, RIPRelSize {
+    UJmpX86() { }
+    @Override public String op() { return "jmp"; }
+    @Override public String label() { return op(); }
+    @Override public StringBuilder _print1( StringBuilder sb, BitSet visited ) {
+        return sb.append("jmp ");
+    }
+    @Override public RegMask regmap(int i) {return null; }
+    @Override public RegMask outregmap() { return null; }
+    @Override public Type compute() { throw Utils.TODO(); }
+    @Override public Node idealize() { throw Utils.TODO(); }
+    @Override public void encoding( Encoding enc ) {
+        enc.jump(this,uctrl());
+        // Short-form jump
+        enc.add1(0xEB).add1(0);
+        //// E9 cd	JMP rel32
+        //enc.add1(0xE9).add4(0);
+    }
+
+    // Delta is from opcode start, but X86 measures from the end of the 2-byte encoding
+    @Override public byte encSize(int delta) { return (byte)(x86_64_v2.imm8(delta-2) ? 2 : 5); }
+
+    // Delta is from opcode start
+    @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) {
+        byte[] bits = enc.bits();
+        if( opLen==2 ) {
+            assert bits[opStart] == (byte)0xEB;
+            delta -= 2;         // Offset from opcode END
+            assert (byte)delta==delta;
+            bits[opStart+1] = (byte)delta;
+        } else {
+            assert bits[opStart] == (byte)0xEB;
+            bits[opStart] = (byte)0xE9; // Long form
+            delta -= 5;         // Offset from opcode END
+            enc.patch4(opStart+1,delta);
+        }
+    }
+
+    @Override public void asm(CodeGen code, SB sb) {
+        CFGNode target = uctrl();
+        //assert target.nOuts() > 1; // Should optimize jmp to empty targets
+        sb.p(label(target));
+    }
+}
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/XorIX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/XorIX86.java
index 47c6be73..2d989a50 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/XorIX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/XorIX86.java
@@ -1,41 +1,11 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.MachConcreteNode;
-import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.node.Node;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-
-public class XorIX86  extends MachConcreteNode implements MachNode {
-
-    final TypeInteger _ti;
-    XorIX86(Node xor, TypeInteger ti) {super(xor); _inputs.pop(); _ti = ti;}
-
-    // Register mask allowed on input i.
-    // This is the normal calling convention
-    @Override public RegMask regmap(int i) { assert i==1; return x86_64_v2.WMASK; }
-    // Register mask allowed as a result.  0 for no register.
-    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form: "ori  xori ^ #imm"
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" ^ #");
-        _ti.print(sb);
-    }
 
+public class XorIX86 extends ImmX86 {
+    XorIX86( Node add, int imm ) { super(add,imm); }
     @Override public String op() { return "xori"; }
+    @Override public String glabel() { return "^"; }
+    @Override int opcode() { return 0x81; }
+    @Override int mod() { return 6; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/XorX86.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/XorX86.java
index 3322d951..86703903 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/XorX86.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/XorX86.java
@@ -1,36 +1,11 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
-import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.LRG;
-import com.seaofnodes.simple.codegen.RegMask;
-import com.seaofnodes.simple.node.MachConcreteNode;
-import com.seaofnodes.simple.node.MachNode;
 import com.seaofnodes.simple.node.Node;
-import com.seaofnodes.simple.type.TypeInteger;
-import java.io.ByteArrayOutputStream;
-
-public class XorX86 extends MachConcreteNode implements MachNode{
-    XorX86(Node xor) {super(xor);}
-
-    @Override public RegMask regmap(int i) {  return x86_64_v2.WMASK; }
-    @Override public RegMask outregmap() { return x86_64_v2.WMASK; }
-
-    // Output is same register as input#1
-    @Override public int twoAddress() { return 1; }
-
-    // Encoding is appended into the byte array; size is returned
-    @Override public int encoding(ByteArrayOutputStream bytes) {
-        throw Utils.TODO();
-    }
-
-    // General form
-    // General form: "xor ^ reg
-    @Override public void asm(CodeGen code, SB sb) {
-        sb.p(code.reg(this)).p(" = ").p(code.reg(in(1))).p(" ^ ").p(code.reg(in(2)));
-    }
 
+public class XorX86 extends RegX86 {
+    XorX86( Node add ) { super(add); }
     @Override public String op() { return "xor"; }
-
+    @Override public String glabel() { return "^"; }
+    @Override int opcode() { return 0x33; }
+    @Override public boolean commutes() { return true; }
 }
diff --git a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java
index aacd2352..2b7fddb1 100644
--- a/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java
+++ b/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java
@@ -1,26 +1,37 @@
 package com.seaofnodes.simple.node.cpus.x86_64_v2;
 
 import com.seaofnodes.simple.Utils;
-import com.seaofnodes.simple.codegen.CodeGen;
-import com.seaofnodes.simple.codegen.LRG;
-import com.seaofnodes.simple.codegen.Machine;
-import com.seaofnodes.simple.codegen.RegMask;
+import com.seaofnodes.simple.codegen.*;
 import com.seaofnodes.simple.node.*;
 import com.seaofnodes.simple.type.*;
 
 public class x86_64_v2 extends Machine {
+    public x86_64_v2( CodeGen code ) {}
     // X86-64 V2.  Includes e.g. SSE4.2 and POPCNT.
     @Override public String name() { return "x86_64_v2"; }
+    @Override public int defaultOpSize() { return 5; }
 
-    static final int RAX =  0, RCX =  1, RDX =  2, RBX =  3, RSP =  4, RBP =  5, RSI =  6, RDI =  7;
-    static final int R08 =  8, R09 =  9, R10 = 10, R11 = 11, R12 = 12, R13 = 13, R14 = 14, R15 = 15;
+    public static final int RAX = 0, RCX = 1, RDX =  2, RBX =  3, RSP =  4, RBP =  5, RSI =  6, RDI =  7;
+    public static final int R08 = 8, R09 = 9, R10 = 10, R11 = 11, R12 = 12, R13 = 13, R14 = 14, R15 = 15;
 
-    static final int XMM0  = 16, XMM1  = 17, XMM2  = 18, XMM3  = 19, XMM4  = 20, XMM5  = 21, XMM6  = 22, XMM7  = 23;
-    static final int XMM8  = 24, XMM9  = 25, XMM10 = 26, XMM11 = 27, XMM12 = 28, XMM13 = 29, XMM14 = 30, XMM15 = 31;
-    static final int FLAGS = 32;
-    static final int MAX_REG = 33;
-    static final int RPC = 33;
+    public static final int XMM0  = 16, XMM1  = 17, XMM2  = 18, XMM3  = 19, XMM4  = 20, XMM5  = 21, XMM6  = 22, XMM7  = 23;
+    public static final int XMM8  = 24, XMM9  = 25, XMM10 = 26, XMM11 = 27, XMM12 = 28, XMM13 = 29, XMM14 = 30, XMM15 = 31;
+    public static final int FLAGS = 32;
+    public static final int MAX_REG = 33;
+    public static final int RPC = 33;
 
+    // Human-readable name for a register number, e.g. "RAX".
+    public static final String[] REGS = new String[]{
+            "rax", "rcx", "rdx", "rbx", "rsp", "rbp", "rsi", "rdi",
+            "r8" , "r9" , "r10", "r11", "r12", "r13", "r14", "r15",
+            "xmm0", "xmm1", "xmm2" , "xmm3" , "xmm4" , "xmm5" , "xmm6" , "xmm7" ,
+            "xmm8", "xmm9", "xmm10", "xmm11", "xmm12", "xmm13", "xmm14", "xmm15",
+            "flags",
+    };
+    // Hard crash for bad register number, fix yer bugs!
+    @Override public String[] regs() { return REGS; }
+
+    public static int XMM_OFFSET = 16;
     // General purpose register mask: pointers and ints, not floats
     static final long RD_BITS = 0b1111111111111111L; // All the GPRs
     static RegMask RMASK = new RegMask(RD_BITS);
@@ -29,49 +40,229 @@ public class x86_64_v2 extends Machine {
     static RegMask WMASK = new RegMask(WR_BITS);
     // Xmm register mask
     static final long FP_BITS = 0b1111111111111111L << XMM0; // All the XMMs
-    static final RegMask XMASK = new RegMask(FP_BITS);
-    static final RegMask FLAGS_MASK = new RegMask(FLAGS);
-    static final RegMask RPC_MASK = new RegMask(RPC);
+    static RegMask XMASK = new RegMask(FP_BITS);
+    static RegMask FLAGS_MASK = new RegMask(FLAGS);
+    static RegMask RPC_MASK = new RegMask(RPC);
 
     static final long SPILLS = -(1L << MAX_REG);
-    static final RegMask SPLIT_MASK = new RegMask(WR_BITS | FP_BITS | (1L<<FLAGS) | SPILLS, -1L );
+    static final RegMask SPLIT_MASK = new RegMask(WR_BITS | FP_BITS /* | (1L<<FLAGS)*/ | SPILLS, -1L );
 
     // Load/store mask; both GPR and FPR
     static RegMask MEM_MASK = new RegMask(WR_BITS | FP_BITS);
 
-    static final RegMask RAX_MASK = new RegMask(RAX);
-    static final RegMask RCX_MASK = new RegMask(RCX);
-    static final RegMask RDX_MASK = new RegMask(RDX);
-    static final RegMask RDI_MASK = new RegMask(RDI);
-    static final RegMask R08_MASK = new RegMask(R08);
-    static final RegMask R09_MASK = new RegMask(R09);
-    static final RegMask RSI_MASK = new RegMask(RSI);
+    public static RegMask RAX_MASK = new RegMask(RAX);
+    public static RegMask RCX_MASK = new RegMask(RCX);
+    public static RegMask RDX_MASK = new RegMask(RDX);
+    public static RegMask RDI_MASK = new RegMask(RDI);
+    public static RegMask R08_MASK = new RegMask(R08);
+    public static RegMask R09_MASK = new RegMask(R09);
+    public static RegMask RSI_MASK = new RegMask(RSI);
+
+    public static RegMask XMM0_MASK = new RegMask(XMM0);
+
+    // Encoding
+    public static int REX = 0x40;
+    public static int REX_W  = 0x48;
+    public static int REX_WR = 0x4C;
+    public static int REX_WRB= 0x4D;
+    public static int REX_WB = 0x49;
+
+    public enum MOD {
+        INDIRECT,               //  [mem]
+        INDIRECT_disp8,         // [mem + 0x12]
+        INDIRECT_disp32,        // [mem + 0x12345678]
+        DIRECT,                 // mem
+    };
 
-    static final RegMask XMM0_MASK = new RegMask(XMM0);
+    // opcode included here
+    // 0F 84 cd	JE  rel32
+    // 0F 85 cd	JNE rel32
+    // 0F 8F cd	JG  rel32
+    // 0F 8C cd	JL  rel32
+    // 0F 8E cd	JLE rel32
+    // 0F 8D cd	JGE rel32
+    static public int jumpop(String op) {
+        return switch (op) {
+        case "==" -> 0x84;
+        case "!=" -> 0x85;
+        case ">"  -> 0x8F;
+        case "<"  -> 0x8C;
+        case "<=" -> 0x8E;
+        case ">=" -> 0x8D;
+        default -> throw new IllegalArgumentException("Too many arguments");
+        };
+    }
 
-    // Human-readable name for a register number, e.g. "RAX".
-    // Hard crash for bad register number, fix yer bugs!
-    static final String[] REGS = new String[] {
-        "rax" , "rcx" , "rdx"  , "rbx"  , "rsp"  , "rbp"  , "rsi"  , "rdi"  ,
-        "r8"  , "r9"  , "r10"  , "r11"  , "r12"  , "r13"  , "r14"  , "r15"  ,
-        "xmm0", "xmm1", "xmm2" , "xmm3" , "xmm4" , "xmm5" , "xmm6" , "xmm7" ,
-        "xmm8", "xmm9", "xmm10", "xmm11", "xmm12", "xmm13", "xmm14", "xmm15",
-        "flags","[rsp-4]",
+    public static int modrm(MOD mod, int reg, int m_r) {
+        if( reg == -1 ) reg=0;  // Missing reg in this flavor
+        // combine all the bits
+        assert 0 <= reg  &&  reg < 16;
+        assert 0 <= m_r  &&  m_r < 16;
+        return (mod.ordinal() << 6) | ((reg & 0x07) << 3) | m_r & 0x07;
+    }
+
+    // 00 000 000
+    // same bit-layout as modrm
+    public static int sib(int scale, int index, int base) {
+        assert 0 <= base  &&  base < 16;
+        assert 0 <= index && index < 16;
+        return (scale << 6) | ((index & 0x07) << 3) | base & 0x07;
+    }
+
+    // reg1 is reg(R)
+    // reg2 is r/mem(B)
+    // reg3 is X(index)
+    // reg4 is X(base)
+
+    // 0 denotes no direct register
+    public static int rex(int reg, int ptr, int idx, boolean wide) {
+        // assuming 64 bit by default so: 0100 1000
+        assert -1 <= reg && reg < 16;
+        assert -1 <= ptr && ptr < 16;
+        assert -1 <= idx && idx < 16;
+
+        int rex = wide ? REX_W : REX;
+        if( 8 <= reg ) rex |= 0b00000100; // REX.R
+        if( 8 <= ptr ) rex |= 0b00000001; // REX.B
+        if( 8 <= idx ) rex |= 0b00000010; // REX.X
+        return rex;
+    }
+
+    public static int rex(int reg, int ptr, int idx) {
+        return rex(reg, ptr, idx, true);
+    }
+
+    // rex for floats.  Return size (0 or 1)
+    // don't need to use REX if 0x40.
+    public static byte rexF(int reg, int ptr, int idx, boolean wide, Encoding enc) {
+        int rex = rex(reg, ptr, idx, wide);
+        if (rex == REX) return 0;
+        enc.add1(rex);
+        return 1;
+    }
+    // Function used for encoding indirect memory addresses
+    // Does not always generate SIB byte e.g index == -1.
+    // -1 denotes empty value, not set - note 0 is different from -1 as it can represent rax.
+    // Looks for best mod locally
+    public static void indirectAdr( int scale, short index, short base, int offset, int reg, Encoding enc ) {
+        // Assume indirect
+        assert 0 <= base && base < 16;
+        assert -1 <= index && index < 16 && index != RSP;
+
+        MOD mod = MOD.INDIRECT;
+        // is 1 byte enough or need more?
+        if( offset != 0 )
+            mod = imm8(offset)
+                    ? MOD.INDIRECT_disp8
+                    : MOD.INDIRECT_disp32;
+
+        if( mod == MOD.INDIRECT && (base == RBP || base == R13) ) {
+            mod = MOD.INDIRECT_disp8;
+        } else if( index == -1 && (base == RSP || base == R12) ) {
+            index = RSP;
+        }
+
+        if( index == -1 ) {
+            enc.add1(modrm(mod, reg, base));
+        } else {
+            enc.add1(modrm(mod, reg, x86_64_v2.RSP));
+            enc.add1(sib(scale, index, base));
+        }
+
+        if( mod == MOD.INDIRECT_disp8 ) {
+            enc.add1(offset);
+        } else if( mod == MOD.INDIRECT_disp32 ) {
+            enc.add4(offset);
+        }
+    }
+
+
+    // Limit of float args passed in registers
+    static RegMask[] XMMS8 = new RegMask[]{
+        new RegMask(XMM0), new RegMask(XMM1), new RegMask(XMM2), new RegMask(XMM3),
+        new RegMask(XMM4), new RegMask(XMM5), new RegMask(XMM6), new RegMask(XMM7),
     };
-    @Override public String reg( int reg ) {
-        return reg < REGS.length ? REGS[reg] : "[rsp+"+(reg-REGS.length)*4+"]";
+
+    // Map from function signature and argument index to register.
+    // Used to set input registers to CallNodes, and ParmNode outputs.
+    @Override public RegMask callArgMask( TypeFunPtr tfp, int idx, int maxArgSlot ) { return callInMask(tfp,idx,maxArgSlot); }
+    static RegMask callInMask( TypeFunPtr tfp, int idx, int maxArgSlot ) {
+        if( idx==0 ) return RPC_MASK;
+        if( idx==1 ) return null;
+        return switch( CodeGen.CODE._callingConv ) {
+        case "SystemV" -> callSys5 (tfp,idx,maxArgSlot);
+        case "Win64"   -> callWin64(tfp,idx,maxArgSlot);
+        default -> throw Utils.TODO();
+        };
+    }
+
+    // Maximum stack args used by this signature
+    @Override public short maxArgSlot( TypeFunPtr tfp ) {
+        return switch( CodeGen.CODE._callingConv ) {
+        case "SystemV" -> maxArgSlotSys5 (tfp);
+        case "Win64"   -> maxArgSlotWin64(tfp);
+        default -> throw Utils.TODO();
+        };
     }
 
-    // WIN64(param passing)
-    static RegMask[] CALLINMASK_WIN64 = new RegMask[] {
+    // Win64 - max *4* args in registers of all kinds; after that on stack.
+    // Stack args land in increasing memory order with empty/mirror slots for
+    // every register.
+    //
+    // foo( int i0, flt f1, int i2, flt f3, int i4, flt f5, int i6, ... )
+    //
+    // -- Prior Frame --
+    // i6
+    // f5
+    // i4
+    // empty mirror, XMM3= f3
+    // empty mirror, R08 = i2
+    // empty mirror, XMM1= f1
+    // empty mirror, RCX = i0
+    // -- Caller Frame; 16b align --
+    // RPC
+    // PAD/ALIGN
+    // -- Callee Frame; 16b align --
+    static RegMask[] WIN64_CALL = new RegMask[] {
         RCX_MASK,
         RDX_MASK,
         R08_MASK,
         R09_MASK,
     };
 
+    static RegMask callWin64(TypeFunPtr tfp, int idx, int maxArgSlot ) {
+        // idx 2,3,4,5 passed in registers, with stack slot mirrors.
+        // idx >= 6 passed on stack, starting at slot#1 (#0 reserved for RPC).
+        if( idx >= 6 )
+            return new RegMask(MAX_REG+maxArgSlot+(idx-2));
+        return tfp.arg(idx-2) instanceof TypeFloat
+            ? XMMS8     [idx-2]
+            : WIN64_CALL[idx-2];
+    }
+    static short maxArgSlotWin64(TypeFunPtr tfp) {
+        return (short)tfp.nargs();
+    }
+
+    // Sys5: max 6 GPRs and 8 FPRS filled first.  Extra args land in increasing
+    // memory order as needed - no mirror space.
+    //
+    // foo( int i0, flt f1, int i2, flt f3, int i4, flt f5, int i6, ... )
+    // RDI =i0, RSI =i2, RDX =i4, RCX =i6, R08 =i8, R09 =i10
+    // XMM0=f1, XMM1=f3, XMM2=f5, XMM3=f7, XMM4=f9, XMM5=f11, XMM6=f13, XMM7=f15
+    //
+    // -- Prior Frame --
+    // f18
+    // i18
+    // f17
+    // i16
+    // i14
+    // i12
+    // -- Caller Frame; 16b align --
+    // RPC
+    // PAD/ALIGN
+    // -- Callee Frame; 16b align --
     // SystemV(param passing)
-    static RegMask[] CALLINMASK_SYSTEMV = new RegMask[] {
+    static RegMask[] SYS5_CALL = new RegMask[] {
         RDI_MASK,
         RSI_MASK,
         RDX_MASK,
@@ -80,285 +271,243 @@ public class x86_64_v2 extends Machine {
         R09_MASK,
     };
 
-    // Limit of float args passed in registers
-    static RegMask[] XMMS4 = new RegMask[]{
-        new RegMask(XMM0), new RegMask(XMM1), new RegMask(XMM2), new RegMask(XMM3),
-    };
-
-    // Map from function signature and argument index to register.
-    // Used to set input registers to CallNodes, and ParmNode outputs.
-    static RegMask callInMask( TypeFunPtr tfp, int idx ) {
-        if( idx==0 ) return RPC_MASK;
-        if( idx==1 ) return null;
-        // Count floats in signature up to index
-        int fcnt=0;
-        for( int i=2; i<idx; i++ )
-            if( tfp.arg(i-2) instanceof TypeFloat )
-                fcnt++;
-        // Floats up to XMMS in XMM registers
-        if( tfp.arg(idx-2) instanceof TypeFloat ) {
-            if( fcnt < XMMS4.length )
-                return XMMS4[fcnt];
-        } else {
-            RegMask[] cargs = switch( CodeGen.CODE._callingConv ) {
-            case "SystemV" -> CALLINMASK_SYSTEMV;
-            case "Win64"   -> CALLINMASK_WIN64;
-            default        -> throw new IllegalArgumentException("Unknown calling convention: "+CodeGen.CODE._callingConv);
-            };
-            if( idx-2-fcnt < cargs.length )
-                return cargs[idx-2-fcnt];
+    static RegMask callSys5(TypeFunPtr tfp, int idx, int maxArgSlot ) {
+        // First 6 integers passed in registers: rdi,rsi,rdx,rcx,r08,r09
+        // First 8 floats passed in registers: xmm0-xmm7
+        int icnt=0, fcnt=0;     // Count of ints, floats
+        for( int i=2; i<idx; i++ ) {
+            if( tfp.arg(i-2) instanceof TypeFloat ) fcnt++;
+            else icnt++;
         }
-        throw Utils.TODO(); // Pass on stack slot
+        int nstk = Math.max(icnt-6,0)+Math.max(fcnt-8,0);
+        return tfp.arg(idx-2) instanceof TypeFloat
+            ? fcnt<8 ? XMMS8    [fcnt] : new RegMask(MAX_REG+maxArgSlot+nstk)
+            : icnt<6 ? SYS5_CALL[icnt] : new RegMask(MAX_REG+maxArgSlot+nstk);
+    }
+    static short maxArgSlotSys5(TypeFunPtr tfp) {
+        int icnt=0, fcnt=0;     // Count of ints, floats
+        for( int i=0; i<tfp.nargs(); i++ ) {
+            if( tfp.arg(i) instanceof TypeFloat ) fcnt++;
+            else icnt++;
+        }
+        int nstk = Math.max(icnt-6,0)+Math.max(fcnt-8,0);
+        return (short)nstk;
     }
 
-    // caller saved(systemv)
     static final long SYSTEM5_CALLER_SAVE =
-        (1L<< RAX) | (1L<< RCX) | (1L<< RDX) |
-        (1L<< RDI) | (1L<< RSI) |
-        (1L<< R08) | (1L<< R09) | (1L<< R10) | (1L<< R11) |
-        (1L<<FLAGS)|           // Flags are killed
+        (1L << RAX) | (1L << RCX) | (1L << RDX) |
+        (1L << RDI) | (1L << RSI) |
+        (1L << R08) | (1L << R09) | (1L << R10) | (1L << R11) |
+        (1L << FLAGS) |           // Flags are killed
         // All FP regs are killed
         FP_BITS;
-    static final RegMask SYSTEM5_CALLER_SAVE_MASK = new RegMask(SYSTEM5_CALLER_SAVE);
 
-    // caller saved(win64)
     static final long WIN64_CALLER_SAVE =
         (1L<< RAX) | (1L<< RCX) | (1L<< RDX) |
         (1L<< R08) | (1L<< R09) | (1L<< R10) | (1L<< R11) |
         (1L<<FLAGS)|           // Flags are killed
         // Only XMM0-XMM5 are killed; XMM6-XMM15 are preserved
         (1L<<XMM0) | (1L<<XMM1) | (1L<<XMM2) | (1L<<XMM3) |
-        (1L<<XMM4) | (1L<<XMM5);
-    static final RegMask WIN64_CALLER_SAVE_MASK = new RegMask(WIN64_CALLER_SAVE);
+        (1L<<XMM4) | (1L<<XMM5) ;
 
-    static RegMask x86CallerSave() {
-        return switch( CodeGen.CODE._callingConv ) {
-        case "SystemV" -> SYSTEM5_CALLER_SAVE_MASK;
-        case "Win64"   ->   WIN64_CALLER_SAVE_MASK;
-        default        -> throw new IllegalArgumentException("Unknown calling convention: "+CodeGen.CODE._callingConv);
-        };
-    }
-    @Override public RegMask callerSave() { return x86CallerSave(); }
-
-    static final RegMask SYSTEM5_CALLEE_SAVE_MASK;
-    static final RegMask   WIN64_CALLEE_SAVE_MASK;
-    static {
-        long callee = ~SYSTEM5_CALLER_SAVE;
-        // Remove the spills
-        callee &= (1L<<MAX_REG)-1;
-        callee &= ~(1L<<FLAGS);
-        callee &= ~(1L<<RSP);
-        SYSTEM5_CALLEE_SAVE_MASK = new RegMask(callee);
-
-        callee = ~WIN64_CALLER_SAVE;
-        // Remove the spills
-        callee &= (1L<<MAX_REG)-1;
-        callee &= ~(1L<<FLAGS);
-        callee &= ~(1L<<RSP);
-        WIN64_CALLEE_SAVE_MASK = new RegMask(callee);
-    }
-    static RegMask x86CalleeSave() {
-        return switch( CodeGen.CODE._callingConv ) {
-        case "SystemV" -> SYSTEM5_CALLEE_SAVE_MASK;
-        case "Win64"   ->   WIN64_CALLEE_SAVE_MASK;
-        default        -> throw new IllegalArgumentException("Unknown calling convention: "+CodeGen.CODE._callingConv);
+    @Override public long callerSave() {
+        return switch (CodeGen.CODE._callingConv) {
+        case "SystemV" -> SYSTEM5_CALLER_SAVE;
+        case "Win64"   ->   WIN64_CALLER_SAVE;
+        default -> throw new IllegalArgumentException("Unknown calling convention: " + CodeGen.CODE._callingConv);
         };
     }
-    @Override public RegMask calleeSave() { return x86CalleeSave(); }
-
-
-    static final RegMask[] WIN64_RET_MASKS, SYS5_RET_MASKS;
-    static {
-        WIN64_RET_MASKS = makeRetMasks(  WIN64_CALLEE_SAVE_MASK);
-         SYS5_RET_MASKS = makeRetMasks(SYSTEM5_CALLEE_SAVE_MASK);
-    }
-    private static RegMask[] makeRetMasks(RegMask mask) {
-        int nSaves = mask.size();
-        RegMask[] masks = new RegMask[4 + nSaves];
-        masks[0] = null;
-        masks[1] = null;     // Memory
-        masks[2] = null;     // Varies, either XMM0 or RAX
-        masks[3] = RPC_MASK;
-        short reg = mask.firstReg();
-        for( int i=0; i<nSaves; i++ ) {
-            masks[i+4] = new RegMask(reg);
-            reg = mask.nextReg(reg);
-        }
-        return masks;
+    @Override public long neverSave() { return 1L<<RSP; }
+    @Override public RegMask retMask( TypeFunPtr tfp ) {
+        return tfp.ret() instanceof TypeFloat ? XMM0_MASK : RAX_MASK;
     }
+    @Override public int rpc() { return RPC; }
 
-    // Return single int/ptr register.  Used by CallEnd output and Return input.
-    static RegMask retMask( TypeFunPtr tfp, int i ) {
-        if( i==2 )
-            return tfp.ret() instanceof TypeFloat ? XMM0_MASK : RAX_MASK;
-        RegMask[] masks = switch( CodeGen.CODE._callingConv ) {
-        case "SystemV" ->  SYS5_RET_MASKS;
-        case "Win64"   -> WIN64_RET_MASKS;
-        default        -> throw new IllegalArgumentException("Unknown calling convention: "+CodeGen.CODE._callingConv);
-        };
-        return masks[i];
-    }
 
     // Create a split op; any register to any register, including stack slots
-    @Override public SplitNode split(String kind, byte round, LRG lrg) {  return new SplitX86(kind,round);  }
+    @Override public SplitNode split(String kind, byte round, LRG lrg) {
+        return new SplitX86(kind, round);
+    }
 
     // Return a MachNode unconditional branch
     @Override public CFGNode jump() {
-        throw Utils.TODO();
-    }
-
-    // Break an infinite loop
-    @Override public IfNode never( CFGNode ctrl ) {
-        throw Utils.TODO();
+        return new UJmpX86();
     }
 
     // Instruction selection
-    @Override public Node instSelect( Node n ) {
-        return switch( n ) {
-        case AddFNode     addf  -> addf(addf);
-        case AddNode      add   -> add(add);
-        case AndNode      and   -> and(and);
-        case BoolNode     bool  -> cmp(bool);
-        case CallEndNode  cend  -> new CallEndX86(cend);
-        case CallNode     call  -> call(call);
-        case CastNode     cast  -> new CastX86(cast);
-        case CProjNode    c     -> new CProjNode(c);
-        case ConstantNode con   -> con(con);
-        case DivFNode     divf  -> new DivFX86(divf);
-        case DivNode      div   -> new DivX86(div);
-        case FunNode      fun   -> new FunX86(fun);
-        case IfNode       iff   -> jmp(iff);
-        case LoadNode     ld    -> ld(ld);
-        case MemMergeNode mem   -> new MemMergeNode(mem);
-        case MulFNode     mulf  -> new MulFX86(mulf);
-        case MulNode      mul   -> mul(mul);
-        case NewNode      nnn   -> new NewX86(nnn);
-        case OrNode       or   ->  or(or);
-        case ParmNode     parm  -> new ParmX86(parm);
-        case PhiNode      phi   -> new PhiNode(phi);
-        case ProjNode     prj   -> prj(prj);
-        case ReadOnlyNode read  -> new ReadOnlyNode(read);
-        case ReturnNode   ret   -> new RetX86(ret,ret.fun());
-        case SarNode      sar   -> sar(sar);
-        case ShlNode      shl   -> shl(shl);
-        case ShrNode      shr   -> shr(shr);
-        case StartNode    start -> new StartNode(start);
-        case StopNode     stop  -> new StopNode(stop);
-        case StoreNode    st    -> st(st);
-        case SubFNode     subf  -> new SubFX86(subf);
-        case SubNode      sub   -> sub(sub);
-        case ToFloatNode  tfn   -> i2f8(tfn);
-        case XorNode      xor   -> xor(xor);
-
-        case LoopNode     loop  -> new LoopNode(loop);
-        case RegionNode   region-> new RegionNode(region);
+    @Override
+    public Node instSelect(Node n) {
+        return switch (n) {
+        case AddFNode    addf -> addf(addf);
+        case AddNode      add -> add(add);
+        case AndNode      and -> and(and);
+        case BoolNode    bool -> cmp(bool);
+        case CProjNode      c -> new CProjNode(c);
+        case CallEndNode cend -> new CallEndX86(cend);
+        case CallNode    call -> call(call);
+        case CastNode    cast -> new CastX86(cast);
+        case ConstantNode con -> con(con);
+        case DivFNode    divf -> new DivFX86(divf);
+        case DivNode      div -> new DivX86(div);
+        case FunNode      fun -> new FunX86(fun);
+        case IfNode       iff -> jmp(iff);
+        case LoadNode      ld -> ld(ld);
+        case MemMergeNode mem -> new MemMergeNode(mem);
+        case MinusNode    neg -> new NegX86(neg);
+        case MulFNode    mulf -> new MulFX86(mulf);
+        case MulNode      mul -> mul(mul);
+        case NewNode      nnn -> new NewX86(nnn);
+        case NotNode      not -> new NotX86(not);
+        case OrNode        or -> or(or);
+        case ParmNode    parm -> new ParmX86(parm);
+        case PhiNode      phi -> new PhiNode(phi);
+        case ProjNode     prj -> prj(prj);
+        case ReadOnlyNode read-> new ReadOnlyNode(read);
+        case ReturnNode   ret -> new RetX86(ret, ret.fun());
+        case SarNode      sar -> sar(sar);
+        case ShlNode      shl -> shl(shl);
+        case ShrNode      shr -> shr(shr);
+        case StartNode  start -> new StartNode(start);
+        case StopNode    stop -> new StopNode(stop);
+        case StoreNode     st -> st(st);
+        case SubFNode    subf -> new SubFX86(subf);
+        case SubNode      sub -> sub(sub);
+        case ToFloatNode  tfn -> i2f8(tfn);
+        case XCtrlNode      x -> new ConstantNode(Type.XCONTROL);
+        case XorNode      xor -> xor(xor);
+
+        case LoopNode loop -> new LoopNode(loop);
+        case RegionNode region -> new RegionNode(region);
         default -> throw Utils.TODO();
         };
     }
 
+    public static boolean imm8( long imm ) { return -128 <= imm && imm <= 127; }
+
+    public static boolean imm32( long imm ) { return (int)imm==imm; }
 
     // Attempt a full LEA-style break down.
-    private Node add( AddNode add ) {
+    private Node add(AddNode add) {
         Node lhs = add.in(1);
         Node rhs = add.in(2);
-        if( lhs instanceof LoadNode ld && ld.nOuts()==1 )
-            return new AddMemX86(add,address(ld),ld.ptr(),idx,off,scale, imm(rhs),val);
+        if( lhs instanceof LoadNode ld && ld.nOuts() == 1 && ld._declaredType.log_size() >= 3)
+            return new AddMemX86(add, address(ld), ld.ptr(), idx, off, scale, 0, rhs);
 
-        if( rhs instanceof LoadNode ld && ld.nOuts()==1 )
-            throw Utils.TODO(); // Swap load sides
+//        if(rhs instanceof LoadNode ld && ld.nOuts() == 1 && ld._declaredType.log_size() >= 3) {
+//            throw Utils.TODO(); // Swap load sides
+//        }
 
         // Attempt a full LEA-style break down.
         // Returns one of AddX86, AddIX86, LeaX86, or LHS
-        if( rhs instanceof ConstantNode off && off._con instanceof TypeInteger toff ) {
+        if( rhs instanceof ConstantNode off2 && off2._con instanceof TypeInteger toff ) {
+            long imm = toff.value();
+            assert imm!=0;        // Folded in peeps
+            if( (int)imm != imm ) // Full 64bit immediate
+                return new AddX86(add);
+            // Now imm <= 32bits
             if( lhs instanceof AddNode ladd )
                 // ((base + (idx << scale)) + off)
-                return _lea(add,ladd.in(1),ladd.in(2),toff.value());
+                return _lea(add, ladd.in(1), ladd.in(2), (int)imm);
             if( lhs instanceof ShlNode shift )
                 // (idx << scale) + off; no base
-                return _lea(add,null,shift,toff.value());
+                return _lea(add, null, shift, (int)imm);
 
             // lhs + rhs1
-            if( toff.value()==0 ) return add;
-            return new AddIX86(add, toff);
+            return new AddIX86(add, (int)imm);
         }
-        return _lea(add,lhs,rhs,0);
+        return _lea(add, lhs, rhs, 0);
     }
 
 
-    private Node addf( AddFNode addf ) {
-        if( addf.in(1) instanceof LoadNode ld && ld.nOuts()==1 )
-            return new AddFMemX86(addf,address(ld),ld.ptr(),idx,off,scale, addf.in(2));
+    private Node addf(AddFNode addf) {
+        if(addf.in(1) instanceof LoadNode ld && ld.nOuts() == 1)
+            return new AddFMemX86(addf, address(ld), ld.ptr(), idx, off, scale, addf.in(2));
 
-        if( addf.in(2) instanceof LoadNode ld && ld.nOuts()==1 )
-            throw Utils.TODO(); // Swap load sides
+//        if(addf.in(2) instanceof LoadNode ld && ld.nOuts() == 1)
+//            throw Utils.TODO(); // Swap load sides
 
         return new AddFX86(addf);
     }
 
 
-    private Node _lea( Node add, Node base, Node idx, long off ) {
-        int scale = 1;
-        if( base instanceof ShlNode && !(idx instanceof ShlNode) ) throw Utils.TODO(); // Bug in canonicalization, should on RHS
+    private Node _lea(Node add, Node base, Node idx, int off) {
+        int scale = 0;
+        if( base instanceof ShlNode && !(idx instanceof ShlNode) )
+            throw Utils.TODO(); // Bug in canonicalization, should on RHS
         if( idx instanceof ShlNode shift && shift.in(2) instanceof ConstantNode shfcon &&
             shfcon._con instanceof TypeInteger tscale && 0 <= tscale.value() && tscale.value() <= 3 ) {
             idx = shift.in(1);
-            scale = 1 << ((int)tscale.value());
+            scale = ((int) tscale.value());
         }
         // (base + idx) + off
-        return off==0 && scale==1
+        return off == 0 && scale == 0
             ? new AddX86(add)
-            : new LeaX86(add,base,idx,scale,off);
+            : new LeaX86(add, base, idx, scale, off);
     }
 
 
     private Node and(AndNode and) {
-        if( and.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti )
-            return new AndIX86(and, ti);
+        if( and.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm32(ti.value()) )
+            return new AndIX86(and, (int)ti.value());
         return new AndX86(and);
     }
 
     private Node call(CallNode call) {
-        if( call.fptr() instanceof ConstantNode con && con._con instanceof TypeFunPtr tfp )
-            return new CallX86(call, tfp);
-        return new CallRX86( call );
+        return call.fptr() instanceof ConstantNode con && con._con instanceof TypeFunPtr tfp
+            ? new CallX86(call, tfp)
+            : new CallRX86(call);
     }
 
     // Because X86 flags, a normal ideal Bool is 2 X86 ops: a "cmp" and at "setz".
     // Ideal If reading from a setz will skip it and use the "cmp" instead.
+    private static boolean swap, unsigned;
     private Node cmp( BoolNode bool ) {
+        swap = unsigned = false;
         Node cmp = _cmp(bool);
-        return new SetX86(cmp,bool.op());
+        return new SetX86(cmp, swap ? IfNode.swap(bool.op()) : bool.op(), unsigned);
     }
-    private Node _cmp( BoolNode bool ) {
+
+    private Node _cmp(BoolNode bool) {
         // Float variant
-        if( bool.isFloat() )
+        if( bool.isFloat() ) {
+            unsigned = true;
             return new CmpFX86(bool);
-
+        }
         Node lhs = bool.in(1);
         Node rhs = bool.in(2);
-        if( lhs instanceof LoadNode ld && ld.nOuts()==1 )
-            return new CmpMemX86(bool,address(ld),ld.ptr(),idx,off,scale, imm(rhs),val,false);
 
-        if( rhs instanceof LoadNode ld && ld.nOuts()==1 )
-            return new CmpMemX86(bool,address(ld),ld.ptr(),idx,off,scale, imm(lhs),val,true);
+        // Since cmp does not record a BOP, SetX/Jmp need to know if the CMP is swapped.
+
+        // Vs memory
+        if( lhs instanceof LoadNode ld && ld.nOuts() == 1 && rhs._type.isa(ld._declaredType) )
+            return new CmpMemX86(bool, address(ld), ld.ptr(), idx, off, scale, imm(rhs), val, false);
+
+        // Operands swap in the encoding directly, no need for Set/Jmp to swap `bop`
+        if( rhs instanceof LoadNode ld && ld.nOuts() == 1 && lhs._type.isa(ld._declaredType))
+            return new CmpMemX86(bool, address(ld), ld.ptr(), idx, off, scale, imm(lhs), val, true );
 
         // Vs immediate
-        if( rhs instanceof ConstantNode con && con._con instanceof TypeInteger ti )
-            return new CmpIX86(bool, ti);
+        if( rhs instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm32(ti.value()) )
+            return new CmpIX86(bool, (int)ti.value(), false);
+
+        // Operand swap compare; Set and Jmp need to swap `bop`
+        if( lhs instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm32(ti.value()) )
+            return new CmpIX86(bool, (int)ti.value(), swap=true);
+
         // x vs y
         return new CmpX86(bool);
     }
 
     private Node con( ConstantNode con ) {
-        if( !con._con.isConstant() ) return new ConstantNode( con ); // Default unknown caller inputs
-        return switch( con._con ) {
-        case TypeInteger ti  -> new IntX86(con);
-        case TypeFloat   tf  -> new FltX86(con);
-        case TypeFunPtr  tfp -> new TFPX86(con);
-        case TypeMemPtr  tmp -> throw Utils.TODO();
-        case TypeNil     tn  -> throw Utils.TODO();
-        // TOP, BOTTOM, XCtrl, Ctrl, etc.  Never any executable code.
-        case Type t -> t==Type.NIL ? new IntX86(con) : new ConstantNode(con);
+        if(!con._con.isConstant()) return new ConstantNode(con); // Default unknown caller inputs
+        return switch (con._con) {
+            case TypeInteger ti -> new IntX86(con);
+            case TypeFloat tf -> new FltX86(con);
+            case TypeFunPtr tfp -> new TFPX86(con);
+            case TypeMemPtr tmp -> throw Utils.TODO();
+            case TypeNil tn -> throw Utils.TODO();
+            // TOP, BOTTOM, XCtrl, Ctrl, etc.  Never any executable code.
+            case Type t -> t == Type.NIL ? new IntX86(con) : new ConstantNode(con);
         };
     }
 
@@ -367,28 +516,30 @@ public class x86_64_v2 extends Machine {
         return new I2f8X86(tfn);
     }
 
-    private Node jmp( IfNode iff ) {
+    private Node jmp(IfNode iff) {
         // If/Bool combos will match to a Cmp/Set which sets flags.
         // Most general arith ops will also set flags, which the Jmp needs directly.
         // Loads do not set the flags, and will need an explicit TEST
-        if( !(iff.in(1) instanceof BoolNode) )
-            iff.setDef(1,new BoolNode.EQ(iff.in(1),new ConstantNode(TypeInteger.ZERO)));
-        return new JmpX86(iff, ((BoolNode)iff.in(1)).op());
+        String op = "!=";
+        if( iff.in(1) instanceof BoolNode bool ) op = swap ? IfNode.swap(bool.op()) : bool.op();
+        else if( iff.in(1)==null ) op = "=="; // Never-node cutout
+        else iff.setDef(1, new BoolNode.NE(iff.in(1), new ConstantNode(TypeInteger.ZERO)));
+        return new JmpX86(iff, op);
     }
 
-    private Node ld( LoadNode ld ) {
-        return new LoadX86(address(ld),ld.ptr(),idx,off,scale);
+    private Node ld(LoadNode ld) {
+        return new LoadX86(address(ld), ld.ptr(), idx, off, scale);
     }
 
     private Node mul(MulNode mul) {
-        return mul.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti
-            ? new MulIX86(mul, ti)
-            : new MulX86(mul);
+        if( mul.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm32(ti.value()) )
+            return new MulIX86(mul, (int)ti.value());
+        return new MulX86(mul);
     }
 
     private Node or(OrNode or) {
-        if( or.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti)
-            return new OrIX86(or, ti);
+        if( or.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm32(ti.value()) )
+            return new OrIX86(or, (int)ti.value());
         return new OrX86(or);
     }
 
@@ -396,21 +547,21 @@ public class x86_64_v2 extends Machine {
         return new ProjX86(prj);
     }
 
-    private Node sar( SarNode sar ) {
-        if( sar.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti)
-            return new SarIX86(sar, ti);
+    private Node sar(SarNode sar) {
+        if( sar.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm8(ti.value()))
+            return new SarIX86(sar, (int)(ti.value() & 0xff) );
         return new SarX86(sar);
     }
 
-    private Node shl( ShlNode shl ) {
-        if( shl.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti )
-            return new ShlIX86(shl, ti);
+    private Node shl(ShlNode shl) {
+        if( shl.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm8(ti.value()))
+            return new ShlIX86(shl, (int)(ti.value() & 0xff) );
         return new ShlX86(shl);
     }
 
-    private Node shr(ShrNode shr) {
-        if( shr.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti )
-            return new ShrIX86(shr, ti);
+    private Node shr( ShrNode shr ) {
+        if( shr.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm8(ti.value()) )
+            return new ShrIX86(shr, (int)(ti.value() & 0xff) );
         return new ShrX86(shr);
     }
 
@@ -418,58 +569,58 @@ public class x86_64_v2 extends Machine {
         // Look for "*ptr op= val"
         Node op = st.val();
         if( op instanceof AddNode ) {
-            if( op.in(1) instanceof LoadNode ld &&
-                ld.in(0)==st.in(0) &&
-                ld.mem()==st.mem() &&
-                ld.ptr()==st.ptr() &&
-                ld.off()==st.off() ) {
-                if( op instanceof AddNode ) {
-                    return new MemAddX86(address(st),st.ptr(),idx,off,scale,imm(op.in(2)),val);
-                }
-                throw Utils.TODO();
-            }
+            if( op.in(1) instanceof LoadNode ld && stld_match(st,ld) )
+                return new MemAddX86(address(st), st.ptr(), idx, off, scale, imm(op.in(2)), val);
+            if( op.in(2) instanceof LoadNode ld && stld_match(st,ld) )
+                return new MemAddX86(address(st), st.ptr(), idx, off, scale, imm(op.in(1)), val);
         }
-
-        return new StoreX86(address(st),st.ptr(),idx,off,scale,imm(st.val()),val);
+        return new StoreX86(address(st), st.ptr(), idx, off, scale, imm(st.val()), val);
+    }
+    private static boolean stld_match(StoreNode st, LoadNode ld ) {
+        return
+            ld.in(0) == st.in(0) &&
+            ld.mem() == st.mem() &&
+            ld.ptr() == st.ptr() &&
+            ld.off() == st.off();
     }
 
-    private Node sub( SubNode sub ) {
+
+    private Node sub (SubNode sub ){
         return sub.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti
-            ? new AddIX86(sub, TypeInteger.constant(-ti.value()))
+            ? new AddIX86(sub, (int)-ti.value())
             : new SubX86(sub);
     }
 
-    private Node xor(XorNode xor) {
-        if(xor.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti)
-            return new XorIX86(xor, ti);
-        throw Utils.TODO();
+    private Node xor (XorNode xor){
+        if( xor.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti && imm32(ti.value()) )
+            return new XorIX86(xor, (int)ti.value());
+        return new XorX86(xor);
     }
 
-
     // Gather X86 addressing mode bits prior to constructing.  This is a
     // builder pattern, but saving the bits in a *local* *global* here to keep
     // mess contained.
     private static int off, scale, imm;
     private static Node idx, val;
-    private <N extends MemOpNode> N address( N mop ) {
+    private <N extends MemOpNode > N address(N mop) {
         off = scale = imm = 0;  // Reset
         idx = val = null;
         Node base = mop.ptr();
         // Skip/throw-away a ReadOnly, only used to typecheck
-        if( base instanceof ReadOnlyNode read ) base = read.in(1);
+        if(base instanceof ReadOnlyNode read) base = read.in(1);
         assert !(base instanceof AddNode) && base._type instanceof TypeMemPtr; // Base ptr always, not some derived
-        if( mop.off() instanceof AddNode add && add.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti ) {
-            off = (int)ti.value();
+        if(mop.off() instanceof AddNode add && add.in(2) instanceof ConstantNode con && con._con instanceof TypeInteger ti) {
+            off = (int) ti.value();
             assert off == ti.value(); // In 32-bit range
             idx = add.in(1);
-            if( idx instanceof ShlNode shift && shift.in(2) instanceof ConstantNode shfcon &&
-                shfcon._con instanceof TypeInteger tscale && 0 <= tscale.value() && tscale.value() <= 3 ) {
+            if(idx instanceof ShlNode shift && shift.in(2) instanceof ConstantNode shfcon &&
+                    shfcon._con instanceof TypeInteger tscale && 0 <= tscale.value() && tscale.value() <= 3) {
                 idx = shift.in(1);
-                scale = (int)tscale.value();
+                scale = (int) tscale.value();
             }
         } else {
-            if( mop.off() instanceof ConstantNode con && con._con instanceof TypeInteger ti ) {
-                off = (int)ti.value();
+            if(mop.off() instanceof ConstantNode con && con._con instanceof TypeInteger ti) {
+                off = (int) ti.value();
                 assert off == ti.value(); // In 32-bit range
             } else {
                 idx = mop.off();
@@ -479,10 +630,10 @@ public class x86_64_v2 extends Machine {
     }
 
     private int imm( Node xval ) {
-        assert val==null && imm==0;
-        if( xval instanceof ConstantNode con && con._con instanceof TypeInteger ti ) {
+        assert val == null && imm == 0;
+        if( xval instanceof ConstantNode con && con._con instanceof TypeInteger ti) {
             val = null;
-            imm = (int)ti.value();
+            imm = (int) ti.value();
             assert imm == ti.value(); // In 32-bit range
         } else {
             val = xval;
diff --git a/src/main/java/com/seaofnodes/simple/print/ASMPrinter.java b/src/main/java/com/seaofnodes/simple/print/ASMPrinter.java
index 1a233aa2..da269d31 100644
--- a/src/main/java/com/seaofnodes/simple/print/ASMPrinter.java
+++ b/src/main/java/com/seaofnodes/simple/print/ASMPrinter.java
@@ -1,11 +1,12 @@
 package com.seaofnodes.simple.print;
 
-import com.seaofnodes.simple.codegen.CodeGen;
 import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.Utils;
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.codegen.Encoding;
 import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.TypeFunPtr;
-import com.seaofnodes.simple.type.TypeMem;
-import com.seaofnodes.simple.type.TypeRPC;
+import com.seaofnodes.simple.type.*;
+import java.util.HashSet;
 
 public abstract class ASMPrinter {
 
@@ -18,17 +19,70 @@ public abstract class ASMPrinter {
         for( int i=0; i<code._cfg._len; i++ )
             if( code._cfg.at(i) instanceof FunNode fun )
                 iadr = print(iadr,sb,code,fun,i);
+
+        // Skip padding
+        while( ((iadr+7) & -8) > iadr )
+            iadr++;
+
+        // constant pool
+        Encoding enc = code._encoding;
+        if(  enc!=null && !enc._bigCons.isEmpty() ) {
+            iadr = (iadr+15)&-16; // pad to 16
+            HashSet<Type> targets = new HashSet<>();
+            sb.p("--- Constant Pool ------").nl();
+            // By log size
+            for( int log = 3; log >= 0; log-- ) {
+                for( Node op : enc._bigCons.keySet() ) {
+                    Encoding.Relo relo = enc._bigCons.get(op);
+                    if( targets.contains(relo._t) ) continue;
+                    targets.add(relo._t);
+                    if( relo._t.log_size()==log ) {
+                        sb.hex2(iadr).p("  ");
+                        if( relo._t instanceof TypeTuple tt ) {
+                            for( Type tx : tt._types ) {
+                                switch( log ) {
+                                case 0: sb.hex1(enc.read1(iadr)); break;
+                                case 1: sb.hex2(enc.read2(iadr)); break;
+                                case 2: sb.hex4(enc.read4(iadr)); break;
+                                case 3: sb.hex8(enc.read8(iadr)); break;
+                                }
+                                iadr += (1<<log);
+                                sb.p(" ");
+                            }
+                        } else {
+                            switch( log ) {
+                            case 0: sb.hex1(enc.read1(iadr)).fix(9-1,""); break;
+                            case 1: sb.hex2(enc.read2(iadr)).fix(9-2,""); break;
+                            case 2: sb.hex4(enc.read4(iadr)).fix(9-4,""); break;
+                            case 3: sb.hex8(enc.read8(iadr)).p(" "); break;
+                            }
+                            iadr += (1<<log);
+                        }
+                        relo._t.print(sb).nl();
+                    }
+                }
+            }
+        }
+
+
         return sb;
     }
 
     private static int print(int iadr, SB sb, CodeGen code, FunNode fun, int cfgidx) {
+        FunNode old=null;
+        if( code._encoding!=null ) {
+            old = code._encoding._fun;
+            code._encoding._fun = fun; // Useful printing after RA
+        }
         // Function header
         sb.nl().p("---");
         if( fun._name != null ) sb.p(fun._name).p(" ");
         fun.sig().print(sb);
         sb.p("---------------------------").nl();
+        iadr = (iadr + 15)&-16; // All function entries padded to 16 align
 
-
+        if( fun._frameAdjust != 0 )
+            iadr = doInst(iadr,sb,code,fun,cfgidx,fun,true,true);
         while( !(code._cfg.at(cfgidx) instanceof ReturnNode) )
             iadr = doBlock(iadr,sb,code,fun,cfgidx++);
 
@@ -36,69 +90,74 @@ public abstract class ASMPrinter {
         sb.p("---");
         fun.sig().print(sb);
         sb.p("---------------------------").nl();
+        if( code._encoding != null )
+            code._encoding._fun = old;
         return iadr;
     }
 
-    static private final int encWidth = 8;
     static private final int opWidth = 5;
     static private final int argWidth = 30;
     static int doBlock(int iadr, SB sb, CodeGen code, FunNode fun, int cfgidx) {
+        final int encWidth = code._mach==null ? 2 : code._mach.defaultOpSize()*2;
         CFGNode bb = code._cfg.at(cfgidx);
         if( bb != fun && !(bb instanceof IfNode) && !(bb instanceof CallEndNode) && !(bb instanceof CallNode)  && !(bb instanceof CProjNode && bb.in(0) instanceof CallEndNode ))
-            sb.p(bb instanceof LoopNode ? "LOOP" : "L").p(bb._nid).p(":").nl();
+            sb.p(label(bb)).p(":").nl();
         if( bb instanceof CallNode ) return iadr;
         final boolean postAlloc = code._phase.ordinal() > CodeGen.Phase.RegAlloc.ordinal();
+        final boolean postEncode= code._phase.ordinal() >=CodeGen.Phase.Encoding.ordinal();
 
-        // Count Phis
-        int nPhi=0;
-        for( ; nPhi<bb.nOuts(); nPhi++ )
-            if( !(bb.out(nPhi) instanceof PhiNode) )
-                break;
-
-        if( nPhi>0 ) {
-            // Post-alloc phi prints all on one line
+        boolean once=false;
+        for( Node n : bb.outs() ) {
+            if( !(n instanceof PhiNode phi) ) continue;
+            if( phi._type instanceof TypeMem || phi._type instanceof TypeRPC ) continue; // Nothing for the hidden ones
+            // Post-RegAlloc phi prints all on one line
             if( postAlloc ) {
-                sb.fix(4," ").p(" ").fix(encWidth,"").p("  ");
-                for( int i=0; i<nPhi; i++ ) {
-                    PhiNode phi = (PhiNode)bb.out(i);
-                    if( !(phi._type instanceof TypeMem || phi._type instanceof TypeRPC) ) // Nothing for the hidden ones
-                        sb.p(phi._label).p(':').p(code.reg(phi)).p(',');
-                }
-                sb.unchar().nl();
-
+                if( !once ) { once=true; sb.fix(4," ").p(" ").fix(encWidth,"").p("  "); }
+                sb.p(phi._label).p(':').p(code.reg(phi,fun)).p(',');
             } else {
-                for( int j=0; j<nPhi; j++ ) {
-                    PhiNode phi = (PhiNode)bb.out(j);
-                    if( phi._type instanceof TypeMem || phi._type instanceof TypeRPC ) continue; // Nothing for the hidden ones
-                    sb.fix(4," ").p(" ").fix(encWidth,"").p("  ").fix(opWidth,phi._label).p(" ");
-                    sb.p(code.reg(phi));
-                    if( !(phi instanceof ParmNode) ) {
-                        sb.p(" = phi( ");
-                        for( int i=1; i<phi.nIns(); i++ )
-                            sb.p("N").p(phi.in(i)._nid).p(",");
-                        sb.unchar().p(" )");
-                    }
-                    sb.nl();
+                // Pre-RegAlloc phi prints one line per
+                sb.fix(4," ").p(" ").fix(encWidth,"").p("  ").fix(opWidth,phi._label).p(" ").p(code.reg(phi,fun));
+                if( phi.getClass() == PhiNode.class ) {
+                    sb.p(" = phi( ");
+                    for( int i=1; i<phi.nIns(); i++ )
+                        sb.p("N").p(phi.in(i)._nid).p(",");
+                    sb.unchar().p(" )");
                 }
+                sb.nl();
             }
         }
+        if( once ) sb.unchar().nl();
 
         // All the non-phis
-        for( int i=nPhi; i<bb.nOuts(); i++ )
-            iadr = doInst(iadr, sb,code,fun,bb,bb.out(i),postAlloc );
+        for( int i=0; i<bb.nOuts(); i++ )
+            if( !(bb.out(i) instanceof PhiNode) )
+                iadr = doInst(iadr, sb,code, fun, cfgidx, bb.out(i),postAlloc, postEncode );
 
         return iadr;
     }
 
-    static int doInst(int iadr, SB sb, CodeGen code, FunNode fun, CFGNode bb, Node n, boolean postAlloc ) {
-        if( n instanceof CProjNode ) return iadr;
-        if( n instanceof CalleeSaveNode && postAlloc ) return iadr;
+    static int doInst( int iadr, SB sb, CodeGen code, FunNode fun, int cfgidx, Node n, boolean postAlloc, boolean postEncode ) {
+        if( n==null || n instanceof CProjNode ) return iadr;
+        if( postAlloc && n instanceof CalleeSaveNode ) return iadr;
+        if( postEncode && n instanceof ProjNode ) return iadr;
+        if( n instanceof MemMergeNode ) return iadr;
+        if( n.getClass() == ConstantNode.class ) return iadr; // Default placeholders
+        final int dopz = code._mach==null ? 2 : code._mach.defaultOpSize();
+        final int encWidth = dopz*2;
 
         // All blocks ending in a Region will need to either fall into or jump
         // to this block.  Until the post-reg-alloc block layout cleanup, we
         // need to assume a jump.  There's no real hardware op here, yet.
-        if( n instanceof RegionNode && !(n instanceof FunNode) ) {
-            sb.hex4(iadr++).p(" ").fix(encWidth,"??").p("  ").fix(opWidth,"JMP").p(" ").fix(argWidth,"L"+n._nid).nl();
+        if( n instanceof RegionNode cfg && !(n instanceof FunNode) ) {
+            if( postEncode ) return iadr; // All jumps inserted already
+            while( cfgidx < code._cfg._len-1 ) {
+                CFGNode next = code._cfg.at(++cfgidx);
+                if( next == n ) return iadr; // Fall-through, no branch
+                if( next.nOuts()>1 )
+                    break;      // Has code in the block, need to jump around
+                // No code in the block, can fall through it
+            }
+            sb.hex2(iadr++).p(" ").fix(encWidth,"??").p("  ").fix(opWidth,"JMP").p(" ").fix(argWidth,label(cfg)).nl();
             return iadr;
         }
 
@@ -106,30 +165,44 @@ public abstract class ASMPrinter {
         // get indent slightly and just print their index & node#
         if( n instanceof ProjNode proj ) {
             if( proj._type instanceof TypeMem ) return iadr; // Nothing for the hidden ones
-            sb.fix(4," ").p(" ").fix(encWidth,"").p("    ").fix(opWidth,proj._label==null ? "---" : proj._label).p(" ").p(code.reg(n)).nl();
+            sb.fix(4," ").p(" ").fix(encWidth,"").p("    ").fix(opWidth,proj._label==null ? "---" : proj._label).p(" ").p(code.reg(n,fun)).nl();
             return iadr;
         }
 
         // ADDR ENCODING  Op--- dst = src op src       // Comment
         // 1234 abcdefgh  ld4   RAX = [Rbase + off]    // Comment
-        sb.hex4(iadr);
-        sb.p(" ");
+        sb.hex2(iadr).p(" ");
 
         // Encoding
-        int size = 1;           // TODO: Fake encoding size
-        iadr += size;
-        sb.fix(encWidth,"??");
+        int fatEncoding = 0;
+        if( code._encoding != null ) {
+            int size = code._encoding._opLen[n._nid];
+            if( code._asmLittle )
+                for( int i=0; i<Math.min(size,dopz); i++ )
+                    sb.hex1(code._encoding._bits.buf()[iadr++]);
+            else {
+                iadr += Math.min(size,dopz);
+                for( int i=0; i<Math.min(size,dopz); i++ )
+                    sb.hex1(code._encoding._bits.buf()[iadr-i-1]);
+            }
+            for( int i=size*2; i<encWidth; i++ )
+                sb.p(" ");
+            fatEncoding = size - (encWidth>>1); // Not-printed parts of encoding
+        } else
+            sb.fix(encWidth,"");
         sb.p("  ");
 
         // Op; generally "ld4" or "call"
-        sb.fix(opWidth, n instanceof MachNode mach ? mach.op() : n.label());
-        sb.p(" ");
+        sb.fix(opWidth, n instanceof MachNode mach ? mach.op() : n.label()).p(" ");
 
         // General asm args
+        String isMultiOp = null;
         if( n instanceof MachNode mach ) {
             int old = sb.len();
             mach.asm(code,sb);
-            sb.fix(argWidth-(sb.len()-old),""); // Pad out
+            int len = sb.len();
+            isMultiOp = isMultiOp(sb,old,len);
+            sb.fix(argWidth-(len-old),""); // Pad out
 
         } else if( !(n._type instanceof TypeMem) ) {
             // Room for some inputs
@@ -150,14 +223,64 @@ public abstract class ASMPrinter {
 
         sb.nl();
 
+        // Printing more op bits than fit
+        if( isMultiOp != null && code._encoding != null ) {
+            // Multiple ops, template style, no RA, no scheduling.  Print out
+            // one-line-per-newline, with encoding bits up front.
+            int size = code._encoding._opLen[n._nid];
+            int off = Math.min(size,dopz);
+            while( isMultiOp!=null ) {
+                sb.hex2(iadr).p(" ");
+                int len = Math.min(size-off,dopz);
+                for( int i=0; i<len; i++ )
+                    sb.hex1(code._encoding._bits.buf()[iadr++]);
+                off += len;
+                for( int i=len; i<dopz; i++ ) sb.p("  ");
+                sb.p("  ");
+                int x = isMultiOp.indexOf('\n');
+                if( x== -1 ) {  // Last line
+                    sb.p(isMultiOp).nl();
+                    isMultiOp = null;
+                } else {
+                    sb.p(isMultiOp.substring(0,x+1)); // Includes the newline
+                    isMultiOp = isMultiOp.substring(x+1);
+                }
+
+            }
+
+        } else if( fatEncoding > 0 ) {
+            // Extra bytes past the default encoding width, all put on a line by
+            // themselves.  X86 special for super long encodings
+            sb.hex2(iadr).p(" ");
+            for( int i=0; i<fatEncoding; i++ )
+                sb.hex1(code._encoding._bits.buf()[iadr++]);
+            sb.nl();
+        }
+
+
         // MultiNodes are immediately followed by projection(s)
         if( !(n instanceof CFGNode) && n instanceof MultiNode ) {
             for( Node proj : n._outputs ) {
-                assert proj instanceof ProjNode;
-                doInst(iadr,sb,code,fun,bb,proj,postAlloc);
+                if( proj instanceof ProjNode ) // it could also be an ante-dep
+                    doInst(iadr,sb,code,fun, cfgidx, proj,postAlloc,postEncode);
             }
         }
 
         return iadr;
     }
+
+    private static String label( CFGNode bb ) {
+        return (bb instanceof LoopNode ? "LOOP" : "L")+bb._nid;
+    }
+
+    private static String isMultiOp(SB sb, int old, int len) {
+        for( int i=old; i<len; i++ )
+            if( sb.at(i)=='\n' ) {
+                String s = sb.subString(i+1,len);
+                sb.setLen(i);
+                return s;
+            }
+        return null;
+    }
+
 }
diff --git a/src/main/java/com/seaofnodes/simple/print/IRPrinter.java b/src/main/java/com/seaofnodes/simple/print/IRPrinter.java
index c91f844b..c6e478c5 100644
--- a/src/main/java/com/seaofnodes/simple/print/IRPrinter.java
+++ b/src/main/java/com/seaofnodes/simple/print/IRPrinter.java
@@ -16,6 +16,7 @@ public abstract class IRPrinter {
     // NNID NNAME DDEF DDEF  [[  UUSE UUSE  ]]  TYPE
     // 1234 sssss 1234 1234 1234 1234 1234 1234 tttttt
     public static SB printLine( Node n, SB sb ) {
+        if( n==null ) return sb;
         sb.p("%4d %-7.7s ".formatted(n._nid,n.label()));
         if( n._inputs==null )
             return sb.p("DEAD\n");
@@ -211,7 +212,8 @@ public abstract class IRPrinter {
                 printLine(n,sb);
                 if( !(n instanceof CFGNode) && n instanceof MultiNode )
                     for( Node use : n._outputs )
-                        printLine(use,sb);
+                        if( use instanceof ProjNode )
+                            printLine(use,sb);
             }
         }
 
@@ -281,7 +283,8 @@ public abstract class IRPrinter {
                         printLine( n, sb, bns, i--, ds,ns );
                         if( n instanceof MultiNode && !(n instanceof CFGNode) ) {
                             for( Node use : n._outputs ) {
-                                printLine(use,sb,bns,bns.indexOf(use),ds,ns);
+                                if( use instanceof ProjNode )
+                                    printLine(use,sb,bns,bns.indexOf(use),ds,ns);
                             }
                         }
                     }
diff --git a/src/main/java/com/seaofnodes/simple/print/JSViewer.java b/src/main/java/com/seaofnodes/simple/print/JSViewer.java
index a2b674c9..76c64c71 100644
--- a/src/main/java/com/seaofnodes/simple/print/JSViewer.java
+++ b/src/main/java/com/seaofnodes/simple/print/JSViewer.java
@@ -72,7 +72,7 @@ public class JSViewer implements AutoCloseable {
     public static void show() { if( SERVER!=null && SHOW ) _show(); }
     private static void _show() {
         // Skip util we at least get the Parse object made
-        if( CODE._phase == null )
+        if( CODE._phase==null || CODE._phase.ordinal() < CodeGen.Phase.Parse.ordinal() )
             return;
         boolean midParse = CODE._phase == CodeGen.Phase.Parse;
         Stack<ScopeNode> xScopes = midParse ? CODE.P._xScopes : null;
diff --git a/src/main/java/com/seaofnodes/simple/type/Type.java b/src/main/java/com/seaofnodes/simple/type/Type.java
index 847235dd..6df4e7ab 100644
--- a/src/main/java/com/seaofnodes/simple/type/Type.java
+++ b/src/main/java/com/seaofnodes/simple/type/Type.java
@@ -103,6 +103,7 @@ public class Type {
     // checks with every type compare, only during interning.
 
     // Factory method which interns "this"
+    @SuppressWarnings("unchecked")
     public  <T extends Type> T intern() {
         T nnn = (T)INTERN.get(this);
         if( nnn==null )
@@ -217,7 +218,7 @@ public class Type {
     // Sizes are expected to be between 1 and 64 bits.
     // Size 0 means this either takes no space (such as a known-zero field)
     // or isn't a scalar to be stored in memory.
-    public int log_size() { throw Utils.TODO(); }
+    public int log_size() { return 3; }
 
     // ----------------------------------------------------------
     // Useful in the debugger, which calls toString everywhere.
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeFunPtr.java b/src/main/java/com/seaofnodes/simple/type/TypeFunPtr.java
index 167a931c..bd64bd81 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeFunPtr.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeFunPtr.java
@@ -44,6 +44,7 @@ public class TypeFunPtr extends TypeNil {
     public static TypeFunPtr TEST  = make((byte)2,TypeTuple.TEST,TypeInteger.BOT,1);
     public static TypeFunPtr TEST0 = make((byte)3,TypeTuple.TEST,TypeInteger.BOT,3);
     public static TypeFunPtr MAIN  = make((byte)3,TypeTuple.MAIN,TypeInteger.BOT,-1);
+    public static TypeFunPtr CALLOC= make((byte)3,TypeTuple.CALLOC,TypeMemPtr.BOT,-1);
     public static void gather(ArrayList<Type> ts) { ts.add(TEST); ts.add(TEST0); ts.add(BOT); ts.add(MAIN); }
 
     @Override
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java b/src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java
index 7e607838..284bf581 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeMemPtr.java
@@ -77,7 +77,7 @@ public class TypeMemPtr extends TypeNil {
     // Is forward-reference
     @Override public boolean isFRef() { return _obj.isFRef(); }
 
-    @Override public int log_size() { return 2; } // (1<<2)==4-byte pointers
+    @Override public int log_size() { return 3; } // (1<<3)==8-byte pointers
 
     @Override int hash() { return _obj.hashCode() ^ super.hash(); }
 
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeStruct.java b/src/main/java/com/seaofnodes/simple/type/TypeStruct.java
index e981b5dc..aa6f2dfd 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeStruct.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeStruct.java
@@ -182,9 +182,12 @@ public class TypeStruct extends Type {
 
     @Override
     public SB print(SB sb) {
+        if( _fields == null ) return sb.p(_name); // Forward reference struct, just print the name
+        if( isAry() ) {
+            if( !isFinal() ) sb.p("!");
+            return sb.p(_name); // Skip printing generic array fields
+        }
         sb.p(_name);
-        if( _fields == null ) return sb; // Forward reference struct, just print the name
-        if( isAry() ) return sb; // Skip printing generic array fields
         sb.p(" {");
         for( Field f : _fields )
             f._type.print(sb).p(f._final ? " " : " !").p(f._fname).p("; ");
diff --git a/src/main/java/com/seaofnodes/simple/type/TypeTuple.java b/src/main/java/com/seaofnodes/simple/type/TypeTuple.java
index 95e35e99..d3b19b52 100644
--- a/src/main/java/com/seaofnodes/simple/type/TypeTuple.java
+++ b/src/main/java/com/seaofnodes/simple/type/TypeTuple.java
@@ -17,6 +17,7 @@ public class TypeTuple extends Type {
     public static final TypeTuple START= make(Type.CONTROL,TypeMem.TOP,TypeInteger.BOT);
     public static final TypeTuple MAIN = make(TypeInteger.BOT);
     public static final TypeTuple RET  = make(Type.CONTROL,TypeMem.BOT,Type.BOTTOM);
+    public static final TypeTuple CALLOC = make(TypeInteger.BOT,TypeInteger.BOT);
 
     public static final TypeTuple IF_BOTH    = make(new Type[]{Type. CONTROL,Type. CONTROL});
     public static final TypeTuple IF_NEITHER = make(new Type[]{Type.XCONTROL,Type.XCONTROL});
@@ -55,6 +56,21 @@ public class TypeTuple extends Type {
         return make(ts);
     }
 
+    @Override public boolean isConstant() {
+        for( Type t : _types )
+            if( !t.isConstant() )
+                return false;
+        return true;
+    }
+
+    @Override public int log_size() {
+        assert isConstant();
+        int log_size = 0;
+        for( Type t : _types )
+            log_size = Math.max(log_size,t.log_size());
+        return log_size;
+    }
+
     public Type ret() { assert _types.length==3; return _types[2]; }
 
     @Override public String str() { return print(new SB()).toString(); }