Re: [PATCH v3 08/14] RISC-V: Adding T-Head MemPair extension

[Richard Henderson]

On 1/24/23 09:59, Christoph Muellner wrote:
> +static bool gen_loadpair_tl(DisasContext *ctx, arg_th_pair *a, MemOp memop,
> +                            int shamt)
> +{
> +    TCGv rd1 = dest_gpr(ctx, a->rd1);
> +    TCGv rd2 = dest_gpr(ctx, a->rd2);
> +    TCGv addr1 = tcg_temp_new();
> +    TCGv addr2 = tcg_temp_new();
> +
> +    addr1 = get_address(ctx, a->rs, a->sh2 << shamt);
> +    if ((memop & MO_SIZE) == MO_64) {
> +        addr2 = get_address(ctx, a->rs, 8 + (a->sh2 << shamt));
> +    } else {
> +        addr2 = get_address(ctx, a->rs, 4 + (a->sh2 << shamt));
> +    }
> +
> +    tcg_gen_qemu_ld_tl(rd1, addr1, ctx->mem_idx, memop);
> +    tcg_gen_qemu_ld_tl(rd2, addr2, ctx->mem_idx, memop);
> +    gen_set_gpr(ctx, a->rd1, rd1);
> +    gen_set_gpr(ctx, a->rd2, rd2);

Since dest_gpr may return cpu_gpr[n], this may update the rd1 before recognizing the 
exception that the second load may generate.  Is that correct?

The manual says that rd1, rd2, and rs1 must not be the same, but you do not 
check this.


r~