Re: [Qemu-devel] [PATCH v2] target-ppc: Fix rlwimi, rlwinm, rlwnm

[Anton Blanchard <anton@samba.org>]

Hi rth,

> In 63ae0915f8ec, I arranged to use a 32-bit rotate, without
> considering the effect of a mask value that wraps around to
> the high bits of the word.

Thanks, that passes my tests.

Tested-by: Anton Blanchard <anton@samba.org>

Anton

> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  target-ppc/translate.c | 73
> +++++++++++++++++++++++++++++++++++--------------- 1 file changed, 51
> insertions(+), 22 deletions(-)
> 
> diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> index b689475..23bc054 100644
> --- a/target-ppc/translate.c
> +++ b/target-ppc/translate.c
> @@ -1636,7 +1636,6 @@ static void gen_rlwimi(DisasContext *ctx)
>          tcg_gen_deposit_tl(t_ra, t_ra, t_rs, sh, me - mb + 1);
>      } else {
>          target_ulong mask;
> -        TCGv_i32 t0;
>          TCGv t1;
>  
>  #if defined(TARGET_PPC64)
> @@ -1645,12 +1644,21 @@ static void gen_rlwimi(DisasContext *ctx)
>  #endif
>          mask = MASK(mb, me);
>  
> -        t0 = tcg_temp_new_i32();
>          t1 = tcg_temp_new();
> -        tcg_gen_trunc_tl_i32(t0, t_rs);
> -        tcg_gen_rotli_i32(t0, t0, sh);
> -        tcg_gen_extu_i32_tl(t1, t0);
> -        tcg_temp_free_i32(t0);
> +        if (mask <= 0xffffffffu) {
> +            TCGv_i32 t0 = tcg_temp_new_i32();
> +            tcg_gen_trunc_tl_i32(t0, t_rs);
> +            tcg_gen_rotli_i32(t0, t0, sh);
> +            tcg_gen_extu_i32_tl(t1, t0);
> +            tcg_temp_free_i32(t0);
> +        } else {
> +#if defined(TARGET_PPC64)
> +            tcg_gen_deposit_i64(t1, t_rs, t_rs, 32, 32);
> +            tcg_gen_rotli_i64(t1, t1, sh);
> +#else
> +            g_assert_not_reached();
> +#endif
> +        }
>  
>          tcg_gen_andi_tl(t1, t1, mask);
>          tcg_gen_andi_tl(t_ra, t_ra, ~mask);
> @@ -1678,20 +1686,28 @@ static void gen_rlwinm(DisasContext *ctx)
>          tcg_gen_ext32u_tl(t_ra, t_rs);
>          tcg_gen_shri_tl(t_ra, t_ra, mb);
>      } else {
> +        target_ulong mask;
>  #if defined(TARGET_PPC64)
>          mb += 32;
>          me += 32;
>  #endif
> -        if (sh == 0) {
> -            tcg_gen_andi_tl(t_ra, t_rs, MASK(mb, me));
> -        } else {
> -            TCGv_i32 t0 = tcg_temp_new_i32();
> +        mask = MASK(mb, me);
>  
> +        if (mask <= 0xffffffffu) {
> +            TCGv_i32 t0 = tcg_temp_new_i32();
>              tcg_gen_trunc_tl_i32(t0, t_rs);
>              tcg_gen_rotli_i32(t0, t0, sh);
> -            tcg_gen_andi_i32(t0, t0, MASK(mb, me));
> +            tcg_gen_andi_i32(t0, t0, mask);
>              tcg_gen_extu_i32_tl(t_ra, t0);
>              tcg_temp_free_i32(t0);
> +        } else {
> +#if defined(TARGET_PPC64)
> +            tcg_gen_deposit_i64(t_ra, t_rs, t_rs, 32, 32);
> +            tcg_gen_rotli_i64(t_ra, t_ra, sh);
> +            tcg_gen_andi_i64(t_ra, t_ra, mask);
> +#else
> +            g_assert_not_reached();
> +#endif
>          }
>      }
>      if (unlikely(Rc(ctx->opcode) != 0)) {
> @@ -1707,24 +1723,37 @@ static void gen_rlwnm(DisasContext *ctx)
>      TCGv t_rb = cpu_gpr[rB(ctx->opcode)];
>      uint32_t mb = MB(ctx->opcode);
>      uint32_t me = ME(ctx->opcode);
> -    TCGv_i32 t0, t1;
> +    target_ulong mask;
>  
>  #if defined(TARGET_PPC64)
>      mb += 32;
>      me += 32;
>  #endif
> +    mask = MASK(mb, me);
>  
> -    t0 = tcg_temp_new_i32();
> -    t1 = tcg_temp_new_i32();
> -    tcg_gen_trunc_tl_i32(t0, t_rb);
> -    tcg_gen_trunc_tl_i32(t1, t_rs);
> -    tcg_gen_andi_i32(t0, t0, 0x1f);
> -    tcg_gen_rotl_i32(t1, t1, t0);
> -    tcg_temp_free_i32(t0);
> +    if (mask <= 0xffffffffu) {
> +        TCGv_i32 t0 = tcg_temp_new_i32();
> +        TCGv_i32 t1 = tcg_temp_new_i32();
> +        tcg_gen_trunc_tl_i32(t0, t_rb);
> +        tcg_gen_trunc_tl_i32(t1, t_rs);
> +        tcg_gen_andi_i32(t0, t0, 0x1f);
> +        tcg_gen_rotl_i32(t1, t1, t0);
> +        tcg_gen_extu_i32_tl(t_ra, t1);
> +        tcg_temp_free_i32(t0);
> +        tcg_temp_free_i32(t1);
> +    } else {
> +#if defined(TARGET_PPC64)
> +        TCGv_i64 t0 = tcg_temp_new_i64();
> +        tcg_gen_andi_i64(t0, t_rb, 0x1f);
> +        tcg_gen_deposit_i64(t_ra, t_rs, t_rs, 32, 32);
> +        tcg_gen_rotl_i64(t_ra, t_ra, t0);
> +        tcg_temp_free_i64(t0);
> +#else
> +        g_assert_not_reached();
> +#endif
> +    }
>  
> -    tcg_gen_andi_i32(t1, t1, MASK(mb, me));
> -    tcg_gen_extu_i32_tl(t_ra, t1);
> -    tcg_temp_free_i32(t1);
> +    tcg_gen_andi_tl(t_ra, t_ra, mask);
>  
>      if (unlikely(Rc(ctx->opcode) != 0)) {
>          gen_set_Rc0(ctx, t_ra);