Re: [Qemu-devel] [PATCH v1 4/5] target-ppc: add vector bit permute doubleword instruction

[Richard Henderson]

On 08/04/2016 06:33 PM, Rajalakshmi Srinivasaraghavan wrote:
> +    uint64_t perm = 0;

Move the variable inside the loop.

> +    VECTOR_FOR_INORDER_I(i, u64) {
> +        perm = 0;
> +        VECTOR_FOR_INORDER_I(j, u16) {

Surely this is more clearly written as

  for (j = 0; j < 8; ++j)

since u16 really has nothing to do with this.

> +            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;
> +        }
> +    }

The final assignment of perm is done in the wrong loop.


r~