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Re: [PATCH] Power/GCC: Implement little-endian SPE operations


On Mon, Jul 7, 2014 at 10:33 AM, Maciej W. Rozycki
<macro@codesourcery.com> wrote:

>> Could you add a short comment explaining what the "0" and "1" labels
>> in vec_perm[01][01]_v2si mean?
>
>  Like this?
>
>   Maciej
>
> gcc-ppc-spe-le-update.diff
> Index: gcc-fsf-trunk-quilt/gcc/config/rs6000/spe.md
> ===================================================================
> --- gcc-fsf-trunk-quilt.orig/gcc/config/rs6000/spe.md   2014-07-07 15:27:54.258937029 +0100
> +++ gcc-fsf-trunk-quilt/gcc/config/rs6000/spe.md        2014-07-07 15:26:43.748937008 +0100
> @@ -438,6 +438,11 @@
>    [(set_attr "type" "vecload")
>     (set_attr  "length" "4")])
>
> +;; Integer vector permutation instructions.  The pairs of digits in the
> +;; names of these instructions indicate the indices, in the memory vector
> +;; element ordering, of the vector elements permuted to the output vector
> +;; from the first and the second input vector respectively.

Yes, that's good. It helps if someone reading the code doesn't need to
reverse engineer the numbering convention of the name.

Thanks, David


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