[Qemu-devel] [PATCH v2] target-arm: Set carry flag correctly for Thumb2 ORNS

[Qemu-devel] [PATCH v2] target-arm: Set carry flag correctly for Thumb2 ORNS

[Peter Maydell]

The code for Thumb2 ORNS (or negated and set flags) was trashing
a TCG input register which was needed later for use in calculating
flags, with the effect that the carry flag was always set with
the wrong sense. Fix this by using the TCG orc op instead of
separate not and or ops.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
Change from v1: use orc as suggested by Aurelien

 target-arm/translate.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/target-arm/translate.c b/target-arm/translate.c
index dbd958b..dd56ac6 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -7326,8 +7326,7 @@ gen_thumb2_data_op(DisasContext *s, int op, int conds, uint32_t shifter_out, TCG
         logic_cc = conds;
         break;
     case 3: /* orn */
-        tcg_gen_not_i32(t1, t1);
-        tcg_gen_or_i32(t0, t0, t1);
+        tcg_gen_orc_i32(t0, t0, t1);
         logic_cc = conds;
         break;
     case 4: /* eor */
-- 
1.7.1

[Qemu-devel] Re: [PATCH v2] target-arm: Set carry flag correctly for Thumb2 ORNS

[Aurelien Jarno]

On Sun, Mar 06, 2011 at 08:32:09PM +0000, Peter Maydell wrote:
> The code for Thumb2 ORNS (or negated and set flags) was trashing
> a TCG input register which was needed later for use in calculating
> flags, with the effect that the carry flag was always set with
> the wrong sense. Fix this by using the TCG orc op instead of
> separate not and or ops.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> Change from v1: use orc as suggested by Aurelien
> 
>  target-arm/translate.c |    3 +--
>  1 files changed, 1 insertions(+), 2 deletions(-)

Thanks, applied.

> diff --git a/target-arm/translate.c b/target-arm/translate.c
> index dbd958b..dd56ac6 100644
> --- a/target-arm/translate.c
> +++ b/target-arm/translate.c
> @@ -7326,8 +7326,7 @@ gen_thumb2_data_op(DisasContext *s, int op, int conds, uint32_t shifter_out, TCG
>          logic_cc = conds;
>          break;
>      case 3: /* orn */
> -        tcg_gen_not_i32(t1, t1);
> -        tcg_gen_or_i32(t0, t0, t1);
> +        tcg_gen_orc_i32(t0, t0, t1);
>          logic_cc = conds;
>          break;
>      case 4: /* eor */
> -- 
> 1.7.1
> 
> 

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net