Re: [Qemu-devel] [Qemu-arm] [PATCH 1/4] target/arm: optimize aarch32 rev16

[Philippe Mathieu-Daudé]

Hi Aurelien,

On 05/16/2017 08:01 PM, Aurelien Jarno wrote:
> Use the same mask to avoid having to load two different constants, as

> suggested by Richard Henderson.

What about
Suggested-by: Richard Henderson <address@hidden> ?

> Signed-off-by: Aurelien Jarno <address@hidden>

Reviewed-by: Philippe Mathieu-Daudé <address@hidden>

> ---
>  target/arm/translate.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/target/arm/translate.c b/target/arm/translate.c
> index 0b5a0bca06..5becb2bb89 100644
> --- a/target/arm/translate.c
> +++ b/target/arm/translate.c
> @@ -339,11 +339,13 @@ static void gen_smul_dual(TCGv_i32 a, TCGv_i32 b)
>  static void gen_rev16(TCGv_i32 var)
>  {
>      TCGv_i32 tmp = tcg_temp_new_i32();
> +    TCGv_i32 mask = tcg_const_i32(0x00ff00ff);
>      tcg_gen_shri_i32(tmp, var, 8);
> -    tcg_gen_andi_i32(tmp, tmp, 0x00ff00ff);
> +    tcg_gen_and_i32(tmp, tmp, mask);
> +    tcg_gen_and_i32(var, var, mask);
>      tcg_gen_shli_i32(var, var, 8);
> -    tcg_gen_andi_i32(var, var, 0xff00ff00);
>      tcg_gen_or_i32(var, var, tmp);
> +    tcg_temp_free_i32(mask);
>      tcg_temp_free_i32(tmp);
>  }