On Wed, 01 May 2024 01:31:25 +0900,
Philippe Mathieu-Daudé wrote:
>
> To easily compare with the SH4 manual, rename:
>
> REG(B11_8) -> Rn
> REG(B7_4) -> Rm
> t0 -> result
>
> Mention how underflow is calculated.
>
> Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
> Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>
> ---
> target/sh4/translate.c | 16 ++++++++++------
> 1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/target/sh4/translate.c b/target/sh4/translate.c
> index 47c0f3404e..e599ab9d1a 100644
> --- a/target/sh4/translate.c
> +++ b/target/sh4/translate.c
> @@ -933,16 +933,20 @@ static void _decode_opc(DisasContext * ctx)
> return;
> case 0x300b: /* subv Rm,Rn */
> {
> - TCGv t0, t1, t2;
> - t0 = tcg_temp_new();
> - tcg_gen_sub_i32(t0, REG(B11_8), REG(B7_4));
> + TCGv Rn = REG(B11_8);
> + TCGv Rm = REG(B7_4);
> + TCGv result, t1, t2;
> +
> + result = tcg_temp_new();
> t1 = tcg_temp_new();
> - tcg_gen_xor_i32(t1, t0, REG(B11_8));
> t2 = tcg_temp_new();
> - tcg_gen_xor_i32(t2, REG(B11_8), REG(B7_4));
> + tcg_gen_sub_i32(result, Rn, Rm);
> + /* T = ((Rn ^ Rm) & (Result ^ Rn)) >> 31 */
> + tcg_gen_xor_i32(t1, result, Rn);
> + tcg_gen_xor_i32(t2, Rn, Rm);
> tcg_gen_and_i32(t1, t1, t2);
> tcg_gen_shri_i32(cpu_sr_t, t1, 31);
> - tcg_gen_mov_i32(REG(B11_8), t0);
> + tcg_gen_mov_i32(Rn, result);
> }
> return;
> case 0x2008: /* tst Rm,Rn */
> --
> 2.41.0
>
Reviewed-by: Yoshinori Sato <ys...@users.sourceforge.jp>
--
Yosinori Sato
