Re: [Qemu-devel] [PATCH] Fix extlh instruction on Alpha

[Aurelien Jarno]

On Thu, Sep 17, 2009 at 03:28:52PM -0400, Vince Weaver wrote:
> 
> The extlh instruction on Alpha currently doesn't work properly.
> It's a combination of a cut/paste bug (16 where it should be 32) as well 
> as a "shift by 64" bug.
> 
> This improves on an earlier patch that used labels, conditional jumps, 
> and local variables.  Thanks go especially to Aurelien Jarno and Andreas 
> Schwab who have a much better eye for bit-wise TCG optimization than I do.
> 
> Vince
> 
> Signed-off-by: Vince Weaver <address@hidden>

Thanks, applied to both master and stable-0.11.

> diff --git a/target-alpha/translate.c b/target-alpha/translate.c
> index 9d2bc45..9e7e9b2 100644
> --- a/target-alpha/translate.c
> +++ b/target-alpha/translate.c
> @@ -524,14 +524,15 @@ static inline void 
> gen_ext_h(void(*tcg_gen_ext_i64)(TCGv t0, TCGv t1),
>              else
>                  tcg_gen_mov_i64(cpu_ir[rc], cpu_ir[ra]);
>          } else {
> -            TCGv tmp1, tmp2;
> +            TCGv tmp1;
>              tmp1 = tcg_temp_new();
> +
>              tcg_gen_andi_i64(tmp1, cpu_ir[rb], 7);
>              tcg_gen_shli_i64(tmp1, tmp1, 3);
> -            tmp2 = tcg_const_i64(64);
> -            tcg_gen_sub_i64(tmp1, tmp2, tmp1);
> -            tcg_temp_free(tmp2);
> +            tcg_gen_neg_i64(tmp1, tmp1);
> +            tcg_gen_andi_i64(tmp1, tmp1, 0x3f);
>              tcg_gen_shl_i64(cpu_ir[rc], cpu_ir[ra], tmp1);
> +
>              tcg_temp_free(tmp1);
>          }
>          if (tcg_gen_ext_i64)
> @@ -1316,7 +1317,7 @@ static inline int translate_one(DisasContext *ctx, 
> uint32_t insn)
>              break;
>          case 0x6A:
>              /* EXTLH */
> -            gen_ext_h(&tcg_gen_ext16u_i64, ra, rb, rc, islit, lit);
> +            gen_ext_h(&tcg_gen_ext32u_i64, ra, rb, rc, islit, lit);
>              break;
>          case 0x72:
>              /* MSKQH */
> 
> 
> 

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