Re: [Qemu-devel] [PATCH v2 25/68] target/arm: Convert Signed multiply, signed and unsigned divide

[Peter Maydell]

On Mon, 19 Aug 2019 at 22:38, Richard Henderson
<address@hidden> wrote:
>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
>  target/arm/translate.c | 463 ++++++++++++++++++-----------------------
>  target/arm/a32.decode  |  22 ++
>  target/arm/t32.decode  |  18 ++
>  3 files changed, 247 insertions(+), 256 deletions(-)
>

> +static bool op_smmla(DisasContext *s, arg_rrrr *a, bool round, bool sub)
> +{
> +    TCGv_i32 t1, t2;
> +
> +    if (s->thumb
> +        ? !arm_dc_feature(s, ARM_FEATURE_THUMB_DSP)
> +        : !ENABLE_ARCH_6) {
> +        return false;
> +    }
> +
> +    t1 = load_reg(s, a->rn);
> +    t2 = load_reg(s, a->rm);
> +    tcg_gen_muls2_i32(t2, t1, t1, t2);
> +
> +    if (a->ra != 15) {
> +        TCGv_i32 t3 = load_reg(s, a->ra);
> +        if (sub) {
> +            tcg_gen_sub_i32(t1, t1, t3);
> +        } else {
> +            tcg_gen_add_i32(t1, t1, t3);
> +        }
> +        tcg_temp_free_i32(t3);
> +    }
> +    if (round) {
> +        tcg_gen_shri_i32(t2, t2, 31);
> +        tcg_gen_add_i32(t1, t1, t2);

Can we keep the comment the old decoder had for this case?


> +    }
> +    tcg_temp_free_i32(t2);
> +    store_reg(s, a->rd, t1);
> +    return true;
> +}
> +

This one:

> -                if (insn & (1 << 4)) {
> -                    /*
> -                     * Adding 0x80000000 to the 64-bit quantity
> -                     * means that we have carry in to the high
> -                     * word when the low word has the high bit set.
> -                     */
> -                    tcg_gen_shri_i32(tmp2, tmp2, 31);
> -                    tcg_gen_add_i32(tmp, tmp, tmp2);
> -                }

Otherwise
Reviewed-by: Peter Maydell <address@hidden>

thanks
-- PMM