sys.io.stdin

Return stdin as a u8[].
Add echo() test.
Bugfix multiple dead fcns (most of sys) removal.  Bugfix Call in Loop not handling mem aliases right.
No outer scope during `sys`.
Several tests flip/flop return order and check exact order; TODO fix the false positives.

18 files changed, 138 insertions, 126 deletions

diff --git a/chapter22/src/main/java/com/seaofnodes/simple/Parser.java b/chapter22/src/main/java/com/seaofnodes/simple/Parser.java
index eae823eb..21d6c359 100644
--- a/chapter22/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter22/src/main/java/com/seaofnodes/simple/Parser.java
@@ -448,8 +448,11 @@ public class Parser {
 
         // At exit the false control is the current control, and
         // the scope is the exit scope after the exit test.
-        _xScopes.pop();
-        _xScopes.push(exit);
+        // During sys parsing, there is no xscope here.
+        if( !_xScopes.isEmpty() ) {
+            _xScopes.pop();
+            _xScopes.push( exit );
+        }
         _scope = exit;
         return ZERO;
     }
@@ -1461,7 +1464,7 @@ public class Parser {
             throw error("Expected a function but got "+expr._type.glb(false).str());
         expr.keep();            // Keep while parsing args
 
-        Ary<Node> args = new Ary<Node>(Node.class);
+        Ary<Node> args = new Ary<>( Node.class );
         args.push(null);        // Space for ctrl,mem
         args.push(null);
         while( !peek(')') ) {
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java b/chapter22/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java
index c3e211ea..74fa1f71 100644
--- a/chapter22/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java
+++ b/chapter22/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java
@@ -174,13 +174,16 @@ public class CodeGen {
         // can call any function) to having a correct (but conservative) CG.
 
         FunNode main = link(_main);
-        for( Node use : _start._outputs )
+        for( int i=0; i<_start.nOuts(); i++ ) {
+            Node use = _start.out(i);
             if( use instanceof FunNode fun &&
                 fun.nIns()==2 && fun.in(1)==_start && fun != main &&
                     (fun._name==null || fun._name.startsWith("sys.")) ) {
                 add(fun).setDef(1,Parser.XCTRL);
                 addAll(fun._outputs);
+                i--;
             }
+        }
         _iter.iterate(this);
 
         _tOpto = (int)(System.currentTimeMillis() - t0);
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java b/chapter22/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java
index 78e2f75f..f76b35ef 100644
--- a/chapter22/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java
+++ b/chapter22/src/main/java/com/seaofnodes/simple/codegen/GlobalCodeMotion.java
@@ -167,7 +167,9 @@ public abstract class GlobalCodeMotion {
                             // Load-use directly defines memory
                             (memuse._type instanceof TypeMem ||
                              // Load-use indirectly defines memory
-                             (memuse._type instanceof TypeTuple tt && tt._types[ld._alias] instanceof TypeMem)) )
+                             (memuse._type instanceof TypeTuple tt && tt._types[ld._alias] instanceof TypeMem) ||
+                             // Load-use use/defs memory
+                             memuse instanceof CallNode) )
                             continue outer;
 
                 // All uses done, schedule
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/node/CallEndMach.java b/chapter22/src/main/java/com/seaofnodes/simple/node/CallEndMach.java
new file mode 100644
index 00000000..47cab07a
--- /dev/null
+++ b/chapter22/src/main/java/com/seaofnodes/simple/node/CallEndMach.java
@@ -0,0 +1,36 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.simple.SB;
+import com.seaofnodes.simple.codegen.*;
+
+public class CallEndMach extends CallEndNode implements MachNode {
+    public CallEndMach( CallEndNode n ) { super(n); }
+    // 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/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/arm/CastARM.java b/chapter22/src/main/java/com/seaofnodes/simple/node/CastMach.java
index a5a4e112..92822433 100644
--- a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/arm/CastARM.java
+++ b/chapter22/src/main/java/com/seaofnodes/simple/node/CastMach.java
@@ -1,18 +1,19 @@
-package com.seaofnodes.simple.node.cpus.arm;
+package com.seaofnodes.simple.node;
 
 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); }
+/**
+ * Cast a pointer to read-only
+ */
+public class CastMach extends CastNode implements MachNode {
+    public CastMach( CastNode n ) { super(n); }
     @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 ")); }
+    @Override public void asm(CodeGen code, SB sb) { sb.p(code.reg(in(1))); }
 }
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/node/ExternNode.java b/chapter22/src/main/java/com/seaofnodes/simple/node/ExternNode.java
index 3c3701c7..33fc0c1e 100644
--- a/chapter22/src/main/java/com/seaofnodes/simple/node/ExternNode.java
+++ b/chapter22/src/main/java/com/seaofnodes/simple/node/ExternNode.java
@@ -20,7 +20,4 @@ public class ExternNode extends ConstantNode {
     @Override public String uniqueName() { return "Extern_" + _nid; }
 
     @Override public boolean eq(Node n) { return this==n; }
-
-    @Override int hash() { return _con.hashCode(); }
-
 }
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java b/chapter22/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java
index 5b923bf0..3fc69be0 100644
--- a/chapter22/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java
+++ b/chapter22/src/main/java/com/seaofnodes/simple/node/MemMergeNode.java
@@ -54,7 +54,8 @@ public class MemMergeNode extends Node {
         MemMergeNode merge = new MemMergeNode(false);
         for( Node n : _inputs )
             merge.addDef(n);
-        merge._mem(1,null);
+        for( int i=1; i<nIns(); i++ )
+            merge._mem(i,null);
         return merge.peephole();
     }
 
@@ -132,7 +133,7 @@ public class MemMergeNode extends Node {
         for( int i=1; i<nIns(); i++ ) {
             if( in(i) instanceof PhiNode phi && phi.region()==scope.ctrl() ) {
                 assert phi.in(2)==null;
-                phi.setDef(2,back.in(i)==scope ? phi : back.in(i)); // Fill backedge
+                phi.setDef(2,back.alias(i)==scope ? phi : back.alias(i)); // Fill backedge
             }
             if( exit_def == scope ) // Replace a lazy-phi on the exit path also
                 exit.alias(i,in(i));
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CastRISC.java b/chapter22/src/main/java/com/seaofnodes/simple/node/ReadOnlyMach.java
index c404aaa5..86d17f9b 100644
--- a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CastRISC.java
+++ b/chapter22/src/main/java/com/seaofnodes/simple/node/ReadOnlyMach.java
@@ -1,18 +1,19 @@
-package com.seaofnodes.simple.node.cpus.riscv;
+package com.seaofnodes.simple.node;
 
 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 CastRISC extends CastNode implements MachNode {
-    public CastRISC( CastNode cast ) { super(cast); }
+/**
+ * Cast a pointer to read-only
+ */
+public class ReadOnlyMach extends ReadOnlyNode implements MachNode {
+    public ReadOnlyMach( ReadOnlyNode n ) { super(n); }
     @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 ")); }
+    @Override public void asm(CodeGen code, SB sb) { sb.p(code.reg(in(1))); }
 }
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java b/chapter22/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java
index e9c25f47..d8fe6286 100644
--- a/chapter22/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java
+++ b/chapter22/src/main/java/com/seaofnodes/simple/node/ReadOnlyNode.java
@@ -2,7 +2,6 @@ package com.seaofnodes.simple.node;
 
 import com.seaofnodes.simple.type.Type;
 import com.seaofnodes.simple.type.TypeMemPtr;
-
 import java.util.BitSet;
 
 /**
@@ -27,4 +26,5 @@ public class ReadOnlyNode extends Node {
             return in(1);
         return null;
     }
+
 }
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallEndARM.java b/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallEndARM.java
deleted file mode 100644
index b3c2f6c2..00000000
--- a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/arm/CallEndARM.java
+++ /dev/null
@@ -1,8 +0,0 @@
-package com.seaofnodes.simple.node.cpus.arm;
-
-import com.seaofnodes.simple.node.CallEndNode;
-import com.seaofnodes.simple.node.MachNode;
-
-public class CallEndARM extends CallEndNode implements MachNode {
-    CallEndARM( CallEndNode cend ) { super(cend); }
-}
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/arm/arm.java b/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/arm/arm.java
index d589dc7d..88a2e8c5 100644
--- a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/arm/arm.java
+++ b/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/arm/arm.java
@@ -645,44 +645,44 @@ public class arm extends Machine {
     // Instruction selection
     @Override public Node instSelect(Node n ) {
         return switch( n ) {
-        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    -> asr(sar);
-        case ShlNode shl    -> lsl(shl);
-        case ShrNode shr    -> lsr(shr);
+        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 CastMach(cast);
+        case CallEndNode cend-> new CallEndMach(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 ReadOnlyMach(read);
+        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 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();
         };
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallEndRISC.java b/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallEndRISC.java
deleted file mode 100644
index 7df68e77..00000000
--- a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/riscv/CallEndRISC.java
+++ /dev/null
@@ -1,8 +0,0 @@
-package com.seaofnodes.simple.node.cpus.riscv;
-
-import com.seaofnodes.simple.node.CallEndNode;
-import com.seaofnodes.simple.node.MachNode;
-
-public class CallEndRISC extends CallEndNode implements MachNode {
-    CallEndRISC( CallEndNode cend ) { super(cend); }
-}
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/riscv/riscv.java b/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/riscv/riscv.java
index c4cde159..c1ad1647 100644
--- a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/riscv/riscv.java
+++ b/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/riscv/riscv.java
@@ -327,8 +327,8 @@ public class riscv extends Machine {
         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 CastNode   cast  -> new CastMach(cast);
+        case CallEndNode cend -> new CallEndMach(cend);
         case CProjNode      c -> new CProjNode(c);
         case ConstantNode con -> con(con);
         case DivFNode    divf -> new DivFRISC(divf);
@@ -346,7 +346,7 @@ public class riscv extends Machine {
         case ParmNode    parm -> new ParmRISC(parm);
         case PhiNode      phi -> new PhiNode(phi);
         case ProjNode     prj -> prj(prj);
-        case ReadOnlyNode read-> new ReadOnlyNode(read);
+        case ReadOnlyNode read-> new ReadOnlyMach(read);
         case ReturnNode   ret -> new RetRISC(ret, ret.fun());
         case SarNode      sar -> sra(sar);
         case ShlNode      shl -> sll(shl);
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallEndX86.java b/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallEndX86.java
deleted file mode 100644
index ce8b993f..00000000
--- a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CallEndX86.java
+++ /dev/null
@@ -1,8 +0,0 @@
-package com.seaofnodes.simple.node.cpus.x86_64_v2;
-
-import com.seaofnodes.simple.node.CallEndNode;
-import com.seaofnodes.simple.node.MachNode;
-
-public class CallEndX86 extends CallEndNode implements MachNode {
-    CallEndX86( CallEndNode cend ) { super(cend); }
-}
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CastX86.java b/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CastX86.java
deleted file mode 100644
index 9537cfb3..00000000
--- a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CastX86.java
+++ /dev/null
@@ -1,16 +0,0 @@
-package com.seaofnodes.simple.node.cpus.x86_64_v2;
-
-import com.seaofnodes.simple.SB;
-import com.seaofnodes.simple.codegen.*;
-import com.seaofnodes.simple.node.CastNode;
-import com.seaofnodes.simple.node.MachNode;
-
-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 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/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpMemX86.java b/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpMemX86.java
index 489853eb..a1845363 100644
--- a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpMemX86.java
+++ b/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/CmpMemX86.java
@@ -11,7 +11,7 @@ public class CmpMemX86 extends MemOpX86 {
     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 );
         _swap = swap;
-        assert !_swap || val() == null || bool.op()=="==" || bool.op()=="!="; // Cannot swap with immediate
+        assert !_swap || val() != null || bool.op()=="==" || bool.op()=="!="; // Cannot swap with immediate
     }
     @Override public String op() { return ((val()==null && _imm==0) ? "test" : "cmp") + _sz; }
     @Override public RegMask outregmap() { return x86_64_v2.FLAGS_MASK; }
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java b/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java
index bf51f2cb..35541346 100644
--- a/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java
+++ b/chapter22/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java
@@ -344,9 +344,9 @@ public class x86_64_v2 extends Machine {
         case AndNode      and -> and(and);
         case BoolNode    bool -> cmp(bool);
         case CProjNode      c -> new CProjNode(c);
-        case CallEndNode cend -> new CallEndX86(cend);
+        case CallEndNode cend -> new CallEndMach(cend);
         case CallNode    call -> call(call);
-        case CastNode    cast -> new CastX86(cast);
+        case CastNode    cast -> new CastMach(cast);
         case ConstantNode con -> con(con);
         case DivFNode    divf -> new DivFX86(divf);
         case DivNode      div -> new DivX86(div);
@@ -363,7 +363,7 @@ public class x86_64_v2 extends Machine {
         case ParmNode    parm -> new ParmX86(parm);
         case PhiNode      phi -> new PhiNode(phi);
         case ProjNode     prj -> prj(prj);
-        case ReadOnlyNode read-> new ReadOnlyNode(read);
+        case ReadOnlyNode read-> new ReadOnlyMach(read);
         case ReturnNode   ret -> new RetX86(ret, ret.fun());
         case SarNode      sar -> sar(sar);
         case ShlNode      shl -> shl(shl);
diff --git a/chapter22/src/main/java/com/seaofnodes/simple/sys/sys.smp b/chapter22/src/main/java/com/seaofnodes/simple/sys/sys.smp
index bc0492e8..4ac925db 100644
--- a/chapter22/src/main/java/com/seaofnodes/simple/sys/sys.smp
+++ b/chapter22/src/main/java/com/seaofnodes/simple/sys/sys.smp
@@ -10,8 +10,8 @@ struct sys {
         {  i32 i64 u32 -> u32 } write = "C";
         // fd  buf len -> len
         {  i32 i64 u32 -> u32 } read = "C";
-        //// status
-        //{  i32 -> i32 } _exit = "C";
+        // status
+        {  i32 -> i32 } _exit = "C";
         // addr len prot flags fd  off -> void*
         {  i64  i64 i32  i32   i32 i32 -> i64 } mmap = "C";
         // mmap flags
@@ -22,6 +22,13 @@ struct sys {
         i32 MAP_PRIVATE = 2;
         i32 MAP_ANON = 32;
     };
+    struct ary {
+        val copy = { u8[] dst, int doff, u8[~] src, int soff, int len ->
+            for( int i=0; i<len; i++ )
+                dst[i+doff] = src[i+soff];
+            return dst;
+        };
+    };
     struct io {
         // Print string to stdout
         val p = { u8[~] str ->
@@ -29,22 +36,23 @@ struct sys {
             return sys.libc.write(1,ptr,str#);
         };
 
-        //// Return stdin as a u8[]
-        //val stdin = { ->
-        //    var buf = new u8[8*1024];
-        //    i64 ptr = buf;
-        //    int len = 0;
-        //    while( true ) {
-        //        int rez = sys.libc.read(0,ptr,buf#);
-        //        if( rez < 0 ) sys.libc._exit(sys.libc.errno);
-        //        if( rez < buf# )
-        //            break;
-        //        sys.libc._exit(-2); // Need to implement
-        //    }
-        //    // Compress
-        //    var rez = new u8[len];
-        //    sys.ary.copy(buf,0,rez,0,len);
-        //    return rez;
-        //};
+        // Return stdin as a u8[]
+        val stdin = { ->
+            var buf = new u8[8*1024];
+            i64 ptr = buf;
+            int len = 0;
+            while( true ) {
+                int rez = sys.libc.read(0,ptr,buf#);
+                if( rez < 0 ) sys.libc._exit(sys.libc.errno);
+                len += rez;
+                if( rez < buf# )
+                    break;
+                sys.libc._exit(-2); // Need to implement
+            }
+            // Compress
+            var dst = new u8[len];
+            return sys.ary.copy(dst,0,buf,0,len);
+        };
+
     };
 };