Re: [PATCH v2 07/13] target/riscv: Properly check SEW in amo_op

[Alistair Francis <alistair23@gmail.com>]

On Thu, Oct 14, 2021 at 6:55 AM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> We're currently assuming SEW <= 3, and the "else" from
> the SEW == 3 must be less.  Use a switch and explicitly
> bound both SEW and SEQ for all cases.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  target/riscv/insn_trans/trans_rvv.c.inc | 26 +++++++++++++------------
>  1 file changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/target/riscv/insn_trans/trans_rvv.c.inc b/target/riscv/insn_trans/trans_rvv.c.inc
> index bbc5c93ef1..91fca4a2d1 100644
> --- a/target/riscv/insn_trans/trans_rvv.c.inc
> +++ b/target/riscv/insn_trans/trans_rvv.c.inc
> @@ -704,18 +704,20 @@ static bool amo_op(DisasContext *s, arg_rwdvm *a, uint8_t seq)
>          gen_helper_exit_atomic(cpu_env);
>          s->base.is_jmp = DISAS_NORETURN;
>          return true;
> -    } else {
> -        if (s->sew == 3) {
> -            if (!is_32bit(s)) {
> -                fn = fnsd[seq];
> -            } else {
> -                /* Check done in amo_check(). */
> -                g_assert_not_reached();
> -            }
> -        } else {
> -            assert(seq < ARRAY_SIZE(fnsw));
> -            fn = fnsw[seq];
> -        }
> +    }
> +
> +    switch (s->sew) {
> +    case 0 ... 2:
> +        assert(seq < ARRAY_SIZE(fnsw));
> +        fn = fnsw[seq];
> +        break;
> +    case 3:
> +        /* XLEN check done in amo_check(). */
> +        assert(seq < ARRAY_SIZE(fnsd));
> +        fn = fnsd[seq];
> +        break;
> +    default:
> +        g_assert_not_reached();
>      }
>
>      data = FIELD_DP32(data, VDATA, MLEN, s->mlen);
> --
> 2.25.1
>
>