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[Qemu-devel] [PATCH] target/arm: Fix sign-extension for SMLAL*

Richard Henderson posted 1 patch 6 years, 2 months ago
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git fetch https://github.com/patchew-project/qemu tags/patchew/20190912183058.17947-1-richard.henderson@linaro.org
Maintainers: Peter Maydell <peter.maydell@linaro.org>
target/arm/translate.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
[Qemu-devel] [PATCH] target/arm: Fix sign-extension for SMLAL*
Posted by Richard Henderson 6 years, 2 months ago 
The 32-bit product should be sign-extended, not zero-extended.

Fixes: ea96b374641b
Reported-by: Laurent Desnogues <laurent.desnogues@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/translate.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/target/arm/translate.c b/target/arm/translate.c
index 34bb280e3d..fd2f0e3048 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -8045,7 +8045,9 @@ static bool op_smlaxxx(DisasContext *s, arg_rrrr *a,
     case 2:
         tl = load_reg(s, a->ra);
         th = load_reg(s, a->rd);
-        t1 = tcg_const_i32(0);
+        /* Sign-extend the 32-bit product to 64 bits.  */
+        t1 = tcg_temp_new_i32();
+        tcg_gen_sari_i32(t1, t0, 31);
         tcg_gen_add2_i32(tl, th, tl, th, t0, t1);
         tcg_temp_free_i32(t0);
         tcg_temp_free_i32(t1);
-- 
2.17.1
Re: [PATCH] target/arm: Fix sign-extension for SMLAL*
Posted by Richard Henderson 6 years ago 
Ping.

On 9/12/19 11:30 AM, Richard Henderson wrote:
> The 32-bit product should be sign-extended, not zero-extended.
> 
> Fixes: ea96b374641b
> Reported-by: Laurent Desnogues <laurent.desnogues@gmail.com>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  target/arm/translate.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/target/arm/translate.c b/target/arm/translate.c
> index 34bb280e3d..fd2f0e3048 100644
> --- a/target/arm/translate.c
> +++ b/target/arm/translate.c
> @@ -8045,7 +8045,9 @@ static bool op_smlaxxx(DisasContext *s, arg_rrrr *a,
>      case 2:
>          tl = load_reg(s, a->ra);
>          th = load_reg(s, a->rd);
> -        t1 = tcg_const_i32(0);
> +        /* Sign-extend the 32-bit product to 64 bits.  */
> +        t1 = tcg_temp_new_i32();
> +        tcg_gen_sari_i32(t1, t0, 31);
>          tcg_gen_add2_i32(tl, th, tl, th, t0, t1);
>          tcg_temp_free_i32(t0);
>          tcg_temp_free_i32(t1);
>
Re: [PATCH] target/arm: Fix sign-extension for SMLAL*
Posted by Peter Maydell 6 years ago 
On Tue, 15 Oct 2019 at 00:42, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Ping.
>
> On 9/12/19 11:30 AM, Richard Henderson wrote:
> > The 32-bit product should be sign-extended, not zero-extended.
> >
> > Fixes: ea96b374641b
> > Reported-by: Laurent Desnogues <laurent.desnogues@gmail.com>
> > Signed-off-by: Richard Henderson <richard.henderson@linaro.org>



Applied to target-arm.next, thanks.

-- PMM
Re: [Qemu-devel] [PATCH] target/arm: Fix sign-extension for SMLAL*
Posted by Philippe Mathieu-Daudé 6 years, 1 month ago 
On 9/12/19 8:30 PM, Richard Henderson wrote:
> The 32-bit product should be sign-extended, not zero-extended.
> 
> Fixes: ea96b374641b
> Reported-by: Laurent Desnogues <laurent.desnogues@gmail.com>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> ---
>  target/arm/translate.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/target/arm/translate.c b/target/arm/translate.c
> index 34bb280e3d..fd2f0e3048 100644
> --- a/target/arm/translate.c
> +++ b/target/arm/translate.c
> @@ -8045,7 +8045,9 @@ static bool op_smlaxxx(DisasContext *s, arg_rrrr *a,
>      case 2:
>          tl = load_reg(s, a->ra);
>          th = load_reg(s, a->rd);
> -        t1 = tcg_const_i32(0);
> +        /* Sign-extend the 32-bit product to 64 bits.  */
> +        t1 = tcg_temp_new_i32();
> +        tcg_gen_sari_i32(t1, t0, 31);
>          tcg_gen_add2_i32(tl, th, tl, th, t0, t1);
>          tcg_temp_free_i32(t0);
>          tcg_temp_free_i32(t1);
>
Re: [Qemu-devel] [PATCH] target/arm: Fix sign-extension for SMLAL*
Posted by Laurent Desnogues 6 years, 1 month ago 
Hello,

On Thu, Sep 12, 2019 at 8:31 PM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> The 32-bit product should be sign-extended, not zero-extended.
>
> Fixes: ea96b374641b
> Reported-by: Laurent Desnogues <laurent.desnogues@gmail.com>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

No more failures on my tests.

Tested-by: Laurent Desnogues <laurent.desnogues@gmail.com>

Thanks,

Laurent

> ---
>  target/arm/translate.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/target/arm/translate.c b/target/arm/translate.c
> index 34bb280e3d..fd2f0e3048 100644
> --- a/target/arm/translate.c
> +++ b/target/arm/translate.c
> @@ -8045,7 +8045,9 @@ static bool op_smlaxxx(DisasContext *s, arg_rrrr *a,
>      case 2:
>          tl = load_reg(s, a->ra);
>          th = load_reg(s, a->rd);
> -        t1 = tcg_const_i32(0);
> +        /* Sign-extend the 32-bit product to 64 bits.  */
> +        t1 = tcg_temp_new_i32();
> +        tcg_gen_sari_i32(t1, t0, 31);
>          tcg_gen_add2_i32(tl, th, tl, th, t0, t1);
>          tcg_temp_free_i32(t0);
>          tcg_temp_free_i32(t1);
> --
> 2.17.1
>

Patchew 2.1-devel-b67e4c2

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