[Qemu-devel] [PATCH] PPC: Depend behavior of cmp instructions only on instruction encoding

[Alexander Graf <agraf@suse.de>]

When running an L=1 cmp instruction on a 64bit PPC CPU with SF off, it
still behaves identical to what it does when SF is on. Remove the implicit
difference in the code.

However, the situation is more complex than that. On 32bit CPUs, L=1
instructions are either treated identical to L=0 instructions (G4) or
treated as illegal instructions (e500mc). Differenciating these cases
is out of scope for the 1.5 release and will follow afterwards. For now
just treat the 32bit CPU, 64bit cmp case as undefined.

Reported-by: Torbjorn Granlund <tg@gmplib.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
 target-ppc/translate.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/target-ppc/translate.c b/target-ppc/translate.c
index a018616..89a4445 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -675,7 +675,7 @@ static inline void gen_set_Rc0(DisasContext *ctx, TCGv reg)
 /* cmp */
 static void gen_cmp(DisasContext *ctx)
 {
-    if (NARROW_MODE(ctx) || !(ctx->opcode & 0x00200000)) {
+    if (!(ctx->opcode & 0x00200000)) {
         gen_op_cmp32(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rB(ctx->opcode)],
                      1, crfD(ctx->opcode));
     } else {
@@ -687,7 +687,7 @@ static void gen_cmp(DisasContext *ctx)
 /* cmpi */
 static void gen_cmpi(DisasContext *ctx)
 {
-    if (NARROW_MODE(ctx) || !(ctx->opcode & 0x00200000)) {
+    if (!(ctx->opcode & 0x00200000)) {
         gen_op_cmpi32(cpu_gpr[rA(ctx->opcode)], SIMM(ctx->opcode),
                       1, crfD(ctx->opcode));
     } else {
@@ -699,7 +699,7 @@ static void gen_cmpi(DisasContext *ctx)
 /* cmpl */
 static void gen_cmpl(DisasContext *ctx)
 {
-    if (NARROW_MODE(ctx) || !(ctx->opcode & 0x00200000)) {
+    if (!(ctx->opcode & 0x00200000)) {
         gen_op_cmp32(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rB(ctx->opcode)],
                      0, crfD(ctx->opcode));
     } else {
@@ -711,7 +711,7 @@ static void gen_cmpl(DisasContext *ctx)
 /* cmpli */
 static void gen_cmpli(DisasContext *ctx)
 {
-    if (NARROW_MODE(ctx) || !(ctx->opcode & 0x00200000)) {
+    if (!(ctx->opcode & 0x00200000)) {
         gen_op_cmpi32(cpu_gpr[rA(ctx->opcode)], UIMM(ctx->opcode),
                       0, crfD(ctx->opcode));
     } else {
-- 
1.6.0.2