* SO and OV reflects overflow of the 64-bit result in 64-bit mode and
  overflow of the low-order 32-bit result in 32-bit mode

* OV32 reflects overflow of the low-order 32-bit independent of the mode

Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
---
 target/ppc/translate.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index dd413de..5d8d109 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -809,10 +809,11 @@ static inline void gen_op_arith_compute_ov(DisasContext *ctx, TCGv arg0,
         tcg_gen_andc_tl(cpu_ov, cpu_ov, t0);
     }
     tcg_temp_free(t0);
+    tcg_gen_extract_tl(cpu_ov32, cpu_ov, 31, 1);
+    tcg_gen_extract_tl(cpu_ov, cpu_ov, 63, 1);
     if (NARROW_MODE(ctx)) {
-        tcg_gen_ext32s_tl(cpu_ov, cpu_ov);
+        tcg_gen_mov_tl(cpu_ov, cpu_ov32);
     }
-    tcg_gen_shri_tl(cpu_ov, cpu_ov, TARGET_LONG_BITS - 1);
     tcg_gen_or_tl(cpu_so, cpu_so, cpu_ov);
 }
 
-- 
2.7.4

On 02/20/2017 09:11 PM, Nikunj A Dadhania wrote:
>      tcg_temp_free(t0);
> +    tcg_gen_extract_tl(cpu_ov32, cpu_ov, 31, 1);
> +    tcg_gen_extract_tl(cpu_ov, cpu_ov, 63, 1);
>      if (NARROW_MODE(ctx)) {
> -        tcg_gen_ext32s_tl(cpu_ov, cpu_ov);
> +        tcg_gen_mov_tl(cpu_ov, cpu_ov32);
>      }
> -    tcg_gen_shri_tl(cpu_ov, cpu_ov, TARGET_LONG_BITS - 1);

Don't compute ov32 only to overwrite it again.  Move the ov32 extraction into 
an else of NARROW_MODE.


r~

Richard Henderson <rth@twiddle.net> writes:

> On 02/20/2017 09:11 PM, Nikunj A Dadhania wrote:
>>      tcg_temp_free(t0);
>> +    tcg_gen_extract_tl(cpu_ov32, cpu_ov, 31, 1);
>> +    tcg_gen_extract_tl(cpu_ov, cpu_ov, 63, 1);
>>      if (NARROW_MODE(ctx)) {
>> -        tcg_gen_ext32s_tl(cpu_ov, cpu_ov);
>> +        tcg_gen_mov_tl(cpu_ov, cpu_ov32);
>>      }
>> -    tcg_gen_shri_tl(cpu_ov, cpu_ov, TARGET_LONG_BITS - 1);
>
> Don't compute ov32 only to overwrite it again.  Move the ov32 extraction into 
> an else of NARROW_MODE.

Sure.

Regards
Nikunj