Re: [RFC PATCH 8/9] target/cris: Use tcg_gen_sextract_tl

[Philippe Mathieu-Daudé]

On 24/10/23 10:53, Philippe Mathieu-Daudé wrote:
> On 24/10/23 02:26, Richard Henderson wrote:
> > On 10/23/23 09:09, Philippe Mathieu-Daudé wrote:
> > > Inspired-by: Richard Henderson <richard.henderson@linaro.org>
> > > Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> > > ---
> > > RFC: please double-check bits
> > > ---
> > >   target/cris/translate.c | 3 +--
> > >   1 file changed, 1 insertion(+), 2 deletions(-)
> > >
> > > diff --git a/target/cris/translate.c b/target/cris/translate.c
> > > index 65b07e1d80..3a161f8f73 100644
> > > --- a/target/cris/translate.c
> > > +++ b/target/cris/translate.c
> > > @@ -336,8 +336,7 @@ static void t_gen_cris_mstep(TCGv d, TCGv a, TCGv 
> > > b, TCGv ccs)
> > >        */
> > >       t = tcg_temp_new();
> > >       tcg_gen_shli_tl(d, a, 1);
> > > -    tcg_gen_shli_tl(t, ccs, 31 - 3);
> > > -    tcg_gen_sari_tl(t, t, 31);
> > > +    tcg_gen_sextract_tl(t, ccs, 3, 1);
> >
> > tcg_gen_sextract_tl(t, ccs, ctz32(N_FLAG), 1);
> >
> > Also, it appears t_gen_cris_mstep consumes CCS without making sure 
> > that it is up-to-date.
>
> Do you mean we first need to call cris_evaluate_flags?
>
> -- >8 --
> diff --git a/target/cris/translate.c b/target/cris/translate.c
> index 3a161f8f73..5eb68b8a63 100644
> --- a/target/cris/translate.c
> +++ b/target/cris/translate.c
> @@ -177,6 +177,8 @@ static const int preg_sizes[] = {
>   #define t_gen_movi_env_TN(member, c) \
>       t_gen_mov_env_TN(member, tcg_constant_tl(c))
>
> +static void cris_evaluate_flags(DisasContext *dc);
> +
>   static inline void t_gen_mov_TN_preg(TCGv tn, int r)
>   {
>       assert(r >= 0 && r <= 15);
> @@ -325,7 +327,7 @@ static void t_gen_cris_dstep(TCGv d, TCGv a, TCGv b)
>       tcg_gen_movcond_tl(TCG_COND_GEU, d, d, b, t, d);
>   }
>
> -static void t_gen_cris_mstep(TCGv d, TCGv a, TCGv b, TCGv ccs)
> +static void t_gen_cris_mstep(DisasContext *dc, TCGv d, TCGv a, TCGv b, 
> TCGv ccs)
>   {
>       TCGv t;
>
> @@ -335,6 +337,7 @@ static void t_gen_cris_mstep(TCGv d, TCGv a, TCGv b, 
> TCGv ccs)
>        *    d += s;
>        */
>       t = tcg_temp_new();
> +    cris_evaluate_flags(dc);
>       tcg_gen_shli_tl(d, a, 1);
>       tcg_gen_sextract_tl(t, ccs, 3, 1);

Err, to be applied before this patch #8.

>       tcg_gen_and_tl(t, t, b);
> @@ -702,7 +705,7 @@ static void cris_alu_op_exec(DisasContext *dc, int op,
>           t_gen_cris_dstep(dst, a, b);
>           break;
>       case CC_OP_MSTEP:
> -        t_gen_cris_mstep(dst, a, b, cpu_PR[PR_CCS]);
> +        t_gen_cris_mstep(dc, dst, a, b, cpu_PR[PR_CCS]);
>           break;
>       case CC_OP_BOUND:
>           tcg_gen_movcond_tl(TCG_COND_LEU, dst, a, b, a, b);
> ---