From 24f682f5b676fd4cbf25592054022d9a410fbcc5 Mon Sep 17 00:00:00 2001
From: Joel Dice <joel.dice@gmail.com>
Date: Mon, 3 Sep 2012 08:44:13 -0600
Subject: [PATCH] fix 64-bit shifts on x86_32 (part 2)

My earlier attempt (fa5d76b) missed an important detail, and somehow I
forgot to test the 32-bit OpenJDK build which made that omission
obvious.  Here's the fix.
---
 src/x86.cpp     | 12 ++++++------
 test/Longs.java |  4 ++++
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/x86.cpp b/src/x86.cpp
index 06a492dcfd..acdb8f1f71 100644
--- a/src/x86.cpp
+++ b/src/x86.cpp
@@ -2186,9 +2186,9 @@ shiftLeftRR(Context* c, UNUSED unsigned aSize, Assembler::Register* a,
             unsigned bSize, Assembler::Register* b)
 {
   if (TargetBytesPerWord == 4 and bSize == 8) {
+    Assembler::Register cx(rcx);
     if (a->low != rcx) {
       c->client->save(rcx);
-      Assembler::Register cx(rcx);
       ResolvedPromise promise(0x3F);
       Assembler::Constant mask(&promise);
       moveRR(c, 4, a, 4, &cx);
@@ -2204,7 +2204,7 @@ shiftLeftRR(Context* c, UNUSED unsigned aSize, Assembler::Register* a,
 
     ResolvedPromise promise(32);
     Assembler::Constant constant(&promise);
-    compareCR(c, aSize, &constant, aSize, a);
+    compareCR(c, aSize, &constant, aSize, &cx);
 
     opcode(c, 0x7c); //jl
     c->code.append(2 + 2);
@@ -2232,9 +2232,9 @@ shiftRightRR(Context* c, UNUSED unsigned aSize, Assembler::Register* a,
              unsigned bSize, Assembler::Register* b)
 {
   if (TargetBytesPerWord == 4 and bSize == 8) {
+    Assembler::Register cx(rcx);
     if (a->low != rcx) {
       c->client->save(rcx);
-      Assembler::Register cx(rcx);
       ResolvedPromise promise(0x3F);
       Assembler::Constant mask(&promise);
       moveRR(c, 4, a, 4, &cx);
@@ -2250,7 +2250,7 @@ shiftRightRR(Context* c, UNUSED unsigned aSize, Assembler::Register* a,
 
     ResolvedPromise promise(32);
     Assembler::Constant constant(&promise);
-    compareCR(c, aSize, &constant, aSize, a);
+    compareCR(c, aSize, &constant, aSize, &cx);
 
     opcode(c, 0x7c); //jl
     c->code.append(2 + 3);
@@ -2281,9 +2281,9 @@ unsignedShiftRightRR(Context* c, UNUSED unsigned aSize, Assembler::Register* a,
                      unsigned bSize, Assembler::Register* b)
 {
   if (TargetBytesPerWord == 4 and bSize == 8) {
+    Assembler::Register cx(rcx);
     if (a->low != rcx) {
       c->client->save(rcx);
-      Assembler::Register cx(rcx);
       ResolvedPromise promise(0x3F);
       Assembler::Constant mask(&promise);
       moveRR(c, 4, a, 4, &cx);
@@ -2299,7 +2299,7 @@ unsignedShiftRightRR(Context* c, UNUSED unsigned aSize, Assembler::Register* a,
 
     ResolvedPromise promise(32);
     Assembler::Constant constant(&promise);
-    compareCR(c, aSize, &constant, aSize, a);
+    compareCR(c, aSize, &constant, aSize, &cx);
 
     opcode(c, 0x7c); //jl
     c->code.append(2 + 2);
diff --git a/test/Longs.java b/test/Longs.java
index 649ec6b2ff..4d9395f7b0 100644
--- a/test/Longs.java
+++ b/test/Longs.java
@@ -385,6 +385,10 @@ public class Longs {
 
     { long b = 0xBEL; int x = 0; int y = 0xFF;
       expect(((b >>> x) & y) == 0xBEL); }
+
+    { long b = 0xFFFFFFFFFFFFFFFFL; int s = 20;
+      expect((b >>> -s) == 0xFFFFF);
+    }
   }
 
 }