Re: [Qemu-devel] [PATCH v2] ppc: Convert op_405_check_{sat,satu} to TCG

[Aurélien Jarno]

On Tue, Oct 28, 2008 at 09:01:39PM +0100, Andreas Färber wrote:
> Replace op_405_check_satu with a conditional movi_tl.
>
> Replace {op,do}_405_check_sat with inline TCG instructions.

Thanks, I applied it as part of commit 5591, "target-ppc: convert 405
MAC instructions to TCG"

> Signed-off-by: Andreas Faerber <address@hidden>
> ---
>  Updated with simplifications suggested by Paul Brook.
>  Still only compile-tested - please verify whether I got the logic  
> right.
>
>  target-ppc/op.c        |   15 ---------------
>  target-ppc/op_helper.c |   12 ------------
>  target-ppc/translate.c |   22 ++++++++++++++++++----
>  3 files changed, 18 insertions(+), 31 deletions(-)
>
> diff --git a/target-ppc/op.c b/target-ppc/op.c
> index bcdb11d..f9b1910 100644
> --- a/target-ppc/op.c
> +++ b/target-ppc/op.c
> @@ -1502,12 +1502,6 @@ void OPPROTO op_405_mullhwu (void)
>      RETURN();
>  }
>
> -void OPPROTO op_405_check_sat (void)
> -{
> -    do_405_check_sat();
> -    RETURN();
> -}
> -
>  void OPPROTO op_405_check_ovu (void)
>  {
>      if (likely(T0 >= T2)) {
> @@ -1518,15 +1512,6 @@ void OPPROTO op_405_check_ovu (void)
>      RETURN();
>  }
>
> -void OPPROTO op_405_check_satu (void)
> -{
> -    if (unlikely(T0 < T2)) {
> -        /* Saturate result */
> -        T0 = UINT32_MAX;
> -    }
> -    RETURN();
> -}
> -
>  void OPPROTO op_load_dcr (void)
>  {
>      do_load_dcr();
> diff --git a/target-ppc/op_helper.c b/target-ppc/op_helper.c
> index 32b3471..e78ba82 100644
> --- a/target-ppc/op_helper.c
> +++ b/target-ppc/op_helper.c
> @@ -1729,18 +1729,6 @@ void do_op_602_mfrom (void)
>
>  / 
> *****************************************************************************/
>  /* Embedded PowerPC specific helpers */
> -void do_405_check_sat (void)
> -{
> -    if (!likely((((uint32_t)T1 ^ (uint32_t)T2) >> 31) ||
> -                !(((uint32_t)T0 ^ (uint32_t)T2) >> 31))) {
> -        /* Saturate result */
> -        if (T2 >> 31) {
> -            T0 = INT32_MIN;
> -        } else {
> -            T0 = INT32_MAX;
> -        }
> -    }
> -}
>
>  /* XXX: to be improved to check access rights when in user-mode */
>  void do_load_dcr (void)
> diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> index a977ea4..2a4a70d 100644
> --- a/target-ppc/translate.c
> +++ b/target-ppc/translate.c
> @@ -5106,10 +5106,24 @@ static always_inline void gen_405_mulladd_insn  
> (DisasContext *ctx,
>      }
>      if (opc3 & 0x02) {
>          /* Saturate */
> -        if (opc3 & 0x01)
> -            gen_op_405_check_sat();
> -        else
> -            gen_op_405_check_satu();
> +        int endLabel = gen_new_label();
> +        if (opc3 & 0x01) {
> +            TCGv tmp = tcg_temp_new(TCG_TYPE_TL);
> +            tcg_gen_xor_tl(tmp, cpu_T[1], cpu_T[2]);
> +            tcg_gen_brcondi_tl(TCG_COND_GE, tmp, 0, endLabel);
> +
> +            tcg_gen_xor_tl(tmp, cpu_T[0], cpu_T[2]);
> +            tcg_gen_brcondi_tl(TCG_COND_LT, tmp, 0, endLabel);
> +
> +            tcg_gen_shri_tl(tmp, cpu_T[2], 31);
> +            tcg_gen_xori_tl(cpu_T[0], tmp, 0x7fffffff);
> +
> +            tcg_temp_free(tmp);
> +        } else {
> +            tcg_gen_brcond_tl(TCG_COND_GEU, cpu_T[0], cpu_T[2],  
> endLabel);
> +            tcg_gen_movi_tl(cpu_T[0], UINT32_MAX);
> +        }
> +        gen_set_label(endLabel);
>      }
>      tcg_gen_mov_tl(cpu_gpr[rt], cpu_T[0]);
>      if (unlikely(Rc) != 0) {
> -- 
> 1.5.6.5
>


>


-- 
  .''`.  Aurelien Jarno             | GPG: 1024D/F1BCDB73
 : :' :  Debian developer           | Electrical Engineer
 `. `'   address@hidden         | address@hidden
   `-    people.debian.org/~aurel32 | www.aurel32.net