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Re: Vector Extensions to C (SSE2 on X86)


Amund Fjellheim <abc@lavacat.com> writes:

> >> Anyone fixing the documentation, then?
> >
> > Volunteers are always welcome.
> >
> > Ian
> 
> I would but I don't think I know enough about what GCC supports and
> not. It would be better if those who do the changes make sure the
> documentation fits, wouldn't it?

Yes, that would be better.

Meanwhile, in the real world, volunteers to get us closer to the ideal
world are always welcome.  It doesn't have to be you, of course.

> If I did the documentation, it'd be
> inaccurate.  Features without documentation are kind of pointless to
> the rest of us.

Intel provides documentation.  I don't think that documentation should
be replicated in the gcc documentation.  What we need in the gcc
documentation is some hint that the Intel documentation is relevant,
and the removal of the inaccurate existing documentation.

Ian

> >> Den 1. aug. 2006 kl. 15.51 skrev Ian Lance Taylor:
> >>
> >>> Amund Fjellheim <abc@lavacat.com> writes:
> >>>
> >>>> GCC has some support for vector instructions through typedef'ed
> >>>> types
> >>>> like this:
> >>>> typedef int v4si __attribute__ ((vector_size (16)));
> >>>>
> >>>> Some normal C operators can be done on these and there are some
> >>>> platform specific built in functions. The X86 functions are
> >>>> listed at
> >>>> http://gcc.gnu.org/onlinedocs/gcc-4.1.1/gcc/X86-Built_002din-
> >>>> Functions.html#X86-Built_002din-Functions , but there are lots of
> >>>> SSE2 instructions missing. Why? I don't see how it could be so hard
> >>>> to implement
> >>>>
> >>>> v4si __builtin_ia32_pslld(v4si, int)
> >>>>
> >>>> and so on, when so many other SSE and SSE2 instructions are there.
> >>>> Also, why aren't they available for C++ programs compiled with g++?
> >>>>
> >>>> Will these things be fixed in future releases of gcc? Anyone know
> >>>> something about the status on this?
> >>>
> >>> It is a documentation failure.  gcc's current goal is to
> >>> implement the
> >>> Intel intrinsic functions, providing mmintrin.h and friends:
> >>>     http://www.intel.com/cd/ids/developer/asmo-na/eng/59644.htm
> >>>
> >>> So, to get pslld, you would use _m_pslld or _m_pslldi, etc.
> >>>
> >>> Ian


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