[Qemu-devel] [PATCH] target-ppc: fixed translation of mcrxr instruction

[Qemu-devel] [PATCH] target-ppc: fixed translation of mcrxr instruction

[Sorav Bansal]

Fixed bug in gen_mcrxr() in target-ppc/translate.c:
The XER[SO], XER[OV], and XER[CA] flags are stored in the least
significant bit (bit 0) of their respective registers. They need
to be shifted left (by their respective offsets) to generate the final
XER value. The old translation code for the 'mcrxr' instruction
was assuming that  the flags are stored in bit 2, and was shifting them
right (incorrectly)

Signed-off-by: Sorav Bansal <sbansal@cse.iitd.ernet.in>
---
 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 4801721..c5d73d5 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -4123,8 +4123,9 @@ static void gen_mcrxr(DisasContext *ctx)
     tcg_gen_trunc_tl_i32(t0, cpu_so);
     tcg_gen_trunc_tl_i32(t1, cpu_ov);
     tcg_gen_trunc_tl_i32(dst, cpu_ca);
-    tcg_gen_shri_i32(t0, t0, 2);
-    tcg_gen_shri_i32(t1, t1, 1);
+    tcg_gen_shli_i32(t0, t0, 3);
+    tcg_gen_shli_i32(t1, t1, 2);
+    tcg_gen_shli_i32(dst, dst, 1);
     tcg_gen_or_i32(dst, dst, t0);
     tcg_gen_or_i32(dst, dst, t1);
     tcg_temp_free_i32(t0);
-- 
1.7.9.5

Re: [Qemu-devel] [PATCH] target-ppc: fixed translation of mcrxr instruction

[Tom Musta]

On 6/17/2014 12:54 AM, Sorav Bansal wrote:
> Fixed bug in gen_mcrxr() in target-ppc/translate.c:
> The XER[SO], XER[OV], and XER[CA] flags are stored in the least
> significant bit (bit 0) of their respective registers. They need
> to be shifted left (by their respective offsets) to generate the final
> XER value. The old translation code for the 'mcrxr' instruction
> was assuming that  the flags are stored in bit 2, and was shifting them
> right (incorrectly)
> 
> Signed-off-by: Sorav Bansal <sbansal@cse.iitd.ernet.in>
> ---
>  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 4801721..c5d73d5 100644
> --- a/target-ppc/translate.c
> +++ b/target-ppc/translate.c
> @@ -4123,8 +4123,9 @@ static void gen_mcrxr(DisasContext *ctx)
>      tcg_gen_trunc_tl_i32(t0, cpu_so);
>      tcg_gen_trunc_tl_i32(t1, cpu_ov);
>      tcg_gen_trunc_tl_i32(dst, cpu_ca);
> -    tcg_gen_shri_i32(t0, t0, 2);
> -    tcg_gen_shri_i32(t1, t1, 1);
> +    tcg_gen_shli_i32(t0, t0, 3);
> +    tcg_gen_shli_i32(t1, t1, 2);
> +    tcg_gen_shli_i32(dst, dst, 1);
>      tcg_gen_or_i32(dst, dst, t0);
>      tcg_gen_or_i32(dst, dst, t1);
>      tcg_temp_free_i32(t0);
> 

Reviewed-by: Tom Musta <tommusta@gmail.com>
Tested-by: Tom Musta <tommusta@gmail.com>

Re: [Qemu-devel] [PATCH] target-ppc: fixed translation of mcrxr instruction

[Alexander Graf]

On 17.06.14 15:26, Tom Musta wrote:
> On 6/17/2014 12:54 AM, Sorav Bansal wrote:
>> Fixed bug in gen_mcrxr() in target-ppc/translate.c:
>> The XER[SO], XER[OV], and XER[CA] flags are stored in the least
>> significant bit (bit 0) of their respective registers. They need
>> to be shifted left (by their respective offsets) to generate the final
>> XER value. The old translation code for the 'mcrxr' instruction
>> was assuming that  the flags are stored in bit 2, and was shifting them
>> right (incorrectly)
>>
>> Signed-off-by: Sorav Bansal <sbansal@cse.iitd.ernet.in>
>> ---
>>   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 4801721..c5d73d5 100644
>> --- a/target-ppc/translate.c
>> +++ b/target-ppc/translate.c
>> @@ -4123,8 +4123,9 @@ static void gen_mcrxr(DisasContext *ctx)
>>       tcg_gen_trunc_tl_i32(t0, cpu_so);
>>       tcg_gen_trunc_tl_i32(t1, cpu_ov);
>>       tcg_gen_trunc_tl_i32(dst, cpu_ca);
>> -    tcg_gen_shri_i32(t0, t0, 2);
>> -    tcg_gen_shri_i32(t1, t1, 1);
>> +    tcg_gen_shli_i32(t0, t0, 3);
>> +    tcg_gen_shli_i32(t1, t1, 2);
>> +    tcg_gen_shli_i32(dst, dst, 1);
>>       tcg_gen_or_i32(dst, dst, t0);
>>       tcg_gen_or_i32(dst, dst, t1);
>>       tcg_temp_free_i32(t0);
>>
> Reviewed-by: Tom Musta <tommusta@gmail.com>
> Tested-by: Tom Musta <tommusta@gmail.com>

Thanks, applied to ppc-next.


Alex