A bit of vector extension documentation

[Bernd Schmidt]

On Thu, 27 Sep 2001, Richard Henderson wrote:
>
> Why not?  We have exposed that interface for quite some time.
> It is used in several packages to get a known 32-bit or 64-bit
> quantity (yes, I know those packages assume 8-bit chars).

Really?  It's not documented though, and that led me to thinking
it could possibly go away/be replaced in the future.

> That aside, is it really any better to expose mode(V4SI) as
> a typedef named "v4si"?

I'm not too fond of the syntax
  typedef int blah __attribute__((mode(xxx)));
mainly because the "int" gets ignored.  It just seems quirky.  But if no
one else sees a problem with it, I'll stick to the original documentation
I wrote.


Bernd