[Qemu-devel] [PULL 26/52] target-ppc: Bug Fix: rlwinm

[Alexander Graf]

From: Tom Musta <address@hidden>

The rlwinm specification includes the ROTL32 operation, which is defined
to be a left rotation of two copies of the least significant 32 bits of
the source GPR.

The current implementation is incorrect on 64-bit implementations in that
it rotates a single copy of the least significant 32 bits, padding with
zeroes in the most significant bits.

Fix the code to properly implement this ROTL32 operation.

Example:
R3 = F7487D82EC6F75DF
rlwinm 3,3,5,12,4

R3 expected : 8DEEBBFD880EBBFD
R3 actual   : 00000000880EBBFD (without this fix)

Signed-off-by: Tom Musta <address@hidden>
Signed-off-by: Alexander Graf <address@hidden>
---
 target-ppc/translate.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/target-ppc/translate.c b/target-ppc/translate.c
index c07bb01..44a8e1e 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -1675,11 +1675,9 @@ static void gen_rlwinm(DisasContext *ctx)
     } else {
         TCGv t0 = tcg_temp_new();
 #if defined(TARGET_PPC64)
-        TCGv_i32 t1 = tcg_temp_new_i32();
-        tcg_gen_trunc_i64_i32(t1, cpu_gpr[rS(ctx->opcode)]);
-        tcg_gen_rotli_i32(t1, t1, sh);
-        tcg_gen_extu_i32_i64(t0, t1);
-        tcg_temp_free_i32(t1);
+        tcg_gen_deposit_i64(t0, cpu_gpr[rS(ctx->opcode)],
+            cpu_gpr[rS(ctx->opcode)], 32, 32);
+        tcg_gen_rotli_i64(t0, t0, sh);
 #else
         tcg_gen_rotli_i32(t0, cpu_gpr[rS(ctx->opcode)], sh);
 #endif
-- 
1.8.1.4