TCG x86/x86-64: use move with zero-extend for loads/stores

Starting with version 4.3, gcc returns the result of a function in
rax/eax/ax/al instead of rax/eax, depending of the return type. As
a consequence we should use a zero extend moe in TCG loads/stores.

See http://gcc.gnu.org/ml/gcc/2008-01/msg00052.html for more details.

A big thanks to malc who founds the problem and wrote the x86 patch.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6011 c046a42c-6fe2-441c-8c8c-71466251a162

diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c
index fa0a2ca..2a6ee83 100644 (file)
--- a/tcg/i386/tcg-target.c
+++ b/tcg/i386/tcg-target.c
@@ -525,7 +525,13 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args,
         tcg_out_modrm(s, 0xbf | P_EXT, data_reg, TCG_REG_EAX);
         break;
     case 0:
+        /* movzbl */
+        tcg_out_modrm(s, 0xb6 | P_EXT, data_reg, TCG_REG_EAX);
+        break;
     case 1:
+        /* movzwl */
+        tcg_out_modrm(s, 0xb7 | P_EXT, data_reg, TCG_REG_EAX);
+        break;
     case 2:
     default:
         tcg_out_mov(s, data_reg, TCG_REG_EAX);

diff --git a/tcg/x86_64/tcg-target.c b/tcg/x86_64/tcg-target.c
index 551ca78..ce58fa1 100644 (file)
--- a/tcg/x86_64/tcg-target.c
+++ b/tcg/x86_64/tcg-target.c
@@ -575,7 +575,13 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args,
         tcg_out_modrm(s, 0x63 | P_REXW, data_reg, TCG_REG_RAX);
         break;
     case 0:
+        /* movzbq */
+        tcg_out_modrm(s, 0xb6 | P_EXT | P_REXW, data_reg, TCG_REG_RAX);
+        break;
     case 1:
+        /* movzwq */
+        tcg_out_modrm(s, 0xb7 | P_EXT | P_REXW, data_reg, TCG_REG_RAX);
+        break;
     case 2:
     default:
         /* movl */