Re: [PATCH 7/9] target/mips: Use tcg_gen_sextract_tl

[Richard Henderson]

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>
> ---
>   target/mips/tcg/mxu_translate.c | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/target/mips/tcg/mxu_translate.c b/target/mips/tcg/mxu_translate.c
> index c517258ac5..6eb73256b2 100644
> --- a/target/mips/tcg/mxu_translate.c
> +++ b/target/mips/tcg/mxu_translate.c
> @@ -3840,8 +3840,7 @@ static void gen_mxu_Q16SAT(DisasContext *ctx)
>               tcg_gen_movi_tl(t0, 255);
>   
>               gen_set_label(l_lo);
> -            tcg_gen_shli_tl(t1, mxu_gpr[XRb - 1], 16);
> -            tcg_gen_sari_tl(t1, t1, 16);
> +            tcg_gen_sextract_tl(t1, mxu_gpr[XRb - 1], 0, 16);

The most simple replacement here is tcg_gen_ext16s_tl.

I'll also note that the entire function should be replaced, e.g.

    TCGv min = tcg_constant_tl(0);
    TCGv max = tcg_constant_tl(0xff);
    TCGv tmp[2];

    tmp[0] = tcg_temp_new();
    tmp[1] = tcg_temp_new();

    for (i = 0; i < 4; i++) {
        int rs = i & 2 ? XRc : XRb;
        TCGv t = tmp[i & 1];

        gen_load_mxu_gpr(t, rs);
        tcg_gen_sextract_tl(t, t, (i & 1) * 16, 16);
        tcg_gen_smax_tl(t, t, min);
        tcg_gen_smin_tl(t, t, max);
        if (i != 0) {
            tcg_gen_shli_tl(t, t, i * 8);
            tcg_gen_or_tl(t, t, tmp[(i - 1) & 1];
        }
    }
    gen_store_mxu_gpr(tmp[1], XRa);


And lots of other similar work within this file.  :-/


r~