>>>>> "Richard" == Richard Henderson <[EMAIL PROTECTED]> writes:
Richard> On Tue, Aug 23, 2005 at 04:32:42PM -0400, Paul Koning wrote:
>> 1. Why do _builtin_ia32_paddusb and similar functions take signed
>> vector arguments, when the hardware primitive is defined to
>> operate on unsigned vectors?
Richard> Because the interface you're actually supposed to be using
Richard> is _mm_adds_pu8, which uses an opaque type. The underlying
Richard> builtins all use signed vectors because it was simple to
Richard> make them all the same.
>> 2. Why are there no sse equivalents of those functions, ones that
>> operate on 128 bit values (i.e., paddusb for v16qi vectors)?
Richard> There are. See _mm_adds_epu8 in emmintrin.h.
Thanks.
The puzzler is that this isn't in the gcc docs. At least not in a
place I could find. Not that the MMX builtins are easy to find,
either...
paul
