Re: [Qemu-devel] [PATCH v2 4/5] target-ppc: add vector bit permute doubleword instruction

[Richard Henderson]

On 08/09/2016 03:42 PM, Rajalakshmi Srinivasaraghavan wrote:
> +void helper_vbpermd(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)
> +{
> +    int i, j;
> +    uint64_t perm = 0;
> +
> +    VECTOR_FOR_INORDER_I(i, u64) {
> +        perm = 0;
> +        for (j = 0; j < 8; j++) {
> +            int index = VBPERMQ_INDEX(b, (i * 8) + j);
> +            if (index < 64) {
> +                uint64_t mask = (1ull << (63 - (index & 0x3F)));
> +                if (a->u64[VBPERMQ_DW(index)] & mask) {
> +                    perm |= (0x80 >> j);
> +                }
> +            }
> +        }
> +        r->u64[i] = perm;
> +    }

You need to care for overlap between R vs {A,B}.


r~