Re: [PATCH 42/56] disas/riscv: Fix rv32 encoding of zext.h

On Sun, 2026-08-09 at 15:35 -0700, Richard Henderson wrote:
> For rv64, pack with rs2 = 0 does not encode zext.h.
> 
> Cc: [email protected]
> Fixes: 02c1b569a15 ("disas/riscv: Add Zb[abcs] instructions")
> Signed-off-by: Richard Henderson <[email protected]>

Reviewed-by: Alistair Francis <[email protected]>

Alistair

> ---
>  disas/riscv.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/disas/riscv.c b/disas/riscv.c
> index f51d45674e..9442a6c115 100644
> --- a/disas/riscv.c
> +++ b/disas/riscv.c
> @@ -3506,9 +3506,10 @@ static const rv_opcode_data
> *decode_inst_opcode(rv_decode *dec, rv_isa isa)
>              case 14: op = rv_op_rem; break;
>              case 15: op = rv_op_remu; break;
>              case 36:
> -                switch ((inst >> 20) & 0b11111) {
> -                case 0: op = rv_op_zext_h; break;
> -                default: op = rv_op_pack; break;
> +                if (isa == rv32 && !((inst >> 20) & 0b11111)) {
> +                    op = rv_op_zext_h;
> +                } else {
> +                    op = rv_op_pack;
>                  }
>                  break;
>              case 39: op = rv_op_packh; break;