Re: [PATCH v3 14/37] target/ppc: implement vstri[bh][lr]

[Richard Henderson <richard.henderson@linaro.org>]

On 2/10/22 23:34, matheus.ferst@eldorado.org.br wrote:
> +#define VSTRI(NAME, ELEM, NUM_ELEMS, LEFT) \
> +void helper_##NAME(CPUPPCState *env, ppc_avr_t *t, ppc_avr_t *b,    \
> +                   target_ulong rc)                                 \
> +{                                                                   \
> +    bool null_found = false;                                        \
> +    int i, idx;                                                     \
> +                                                                    \
> +    for (i = 0; i < NUM_ELEMS; i++) {                               \
> +        idx = LEFT ? i : NUM_ELEMS - i - 1;                         \
> +        if (b->Vsr##ELEM(idx)) {                                    \
> +            t->Vsr##ELEM(idx) = b->Vsr##ELEM(idx);                  \
> +        } else {                                                    \
> +            null_found = true;                                      \
> +            break;                                                  \
> +        }                                                           \
> +    }                                                               \
> +                                                                    \
> +    for (; i < NUM_ELEMS; i++) {                                    \
> +        idx = LEFT ? i : NUM_ELEMS - i - 1;                         \
> +        t->Vsr##ELEM(idx) = 0;                                      \
> +    }                                                               \
> +                                                                    \
> +    if (rc) {                                                       \
> +        env->crf[6] = null_found ? 0b0010 : 0;                      \
> +    }                                                               \
> +}

The only reason you're passing in env is for crf[6], which requires you to pass in a 
second argument.  And you're not using the return value.

It would be better to always return the rc value, and only conditionally assign it.
E.g.

     if (a->rc) {
         gen_helper(cpu_crf[6], vrt, vrb);
     } else {
         TCGv_i32 discard = tcg_temp_new_i32();
         gen_helper(discard, vrt, vrb);
         tcg_temp_free_i32(discard);
     }

r~