From bb97129daa1504d67a8e3a76f16d6db15f7e5e7b Mon Sep 17 00:00:00 2001
From: Cliff Click <cliffc@acm.org>
Date: Sat, 5 Apr 2025 15:55:48 -0700
Subject: Float uses unsigned compare

---
 .../java/com/seaofnodes/simple/node/cpus/x86_64_v2/SetX86.java |  8 +++++---
 .../com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java   | 10 ++++++----
 2 files changed, 11 insertions(+), 7 deletions(-)

(limited to 'chapter21/src/main/java/com')

diff --git a/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SetX86.java b/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SetX86.java
index b684b4c4..11a0c6e0 100644
--- a/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SetX86.java
+++ b/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/SetX86.java
@@ -8,13 +8,15 @@ import com.seaofnodes.simple.node.*;
 // 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; }
@@ -29,8 +31,8 @@ public class SetX86 extends MachConcreteNode implements MachNode {
         enc.add1(0x0F);         // opcode
         enc.add1(switch (_bop) {
             case "==" -> 0x94;  // SETE
-            case "<"  -> 0x9C;  // SETL
-            case "<=" -> 0x96; //0X9E;  // SETLE
+            case "<"  -> _unsigned ? 0x92 : 0x9C;  // SETB /SETL
+            case "<=" -> _unsigned ? 0x96 : 0x9E;  // SETBE/SETLE
             default -> throw Utils.TODO();
             });
         enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.DIRECT, 0, dst));
diff --git a/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java b/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java
index 98b14a3c..a8396f2e 100644
--- a/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java
+++ b/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/x86_64_v2.java
@@ -502,17 +502,19 @@ public class x86_64_v2 extends Machine {
 
     // 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;
+    private static boolean swap, unsigned;
     private Node cmp( BoolNode bool ) {
-        swap = false;
+        swap = unsigned = false;
         Node cmp = _cmp(bool);
-        return new SetX86(cmp, swap ? IfNode.swap(bool.op()) : bool.op());
+        return new SetX86(cmp, swap ? IfNode.swap(bool.op()) : bool.op(), unsigned);
     }
 
     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);
 
-- 
cgit v1.2.3