Re: [vox-tech] gcc 3.0

[Bill Broadley <bill@math.ucMAPSdavis.edu>]

On Sat, Mar 03, 2001 at 03:05:17PM -0800, Harry Souders wrote:
> 
> Sorry for the dumb question, but what is SSE?

Basically MMX version 2, I've also heard it called KNI, in any case
it's the "extra" instructions that intel includes for doing Multimedia
kinda instructions including floating point.

> And, by x87 FP stack, do you mean the x86 chips 87 Floating Point
> coprocessor?

Yes, is later cpu's (after the 486) they were included.

> And it only does one FP instruction per cycle (cause I
> thought it did more around the time of 486 or early pentium chips)?

I believe since the pentium ish it did 1 single or 0.5 double
precision ops per cycle.  The biggest problem is that stack
has top of stack/bottom of stack broken, so you end up with
less efficiency then you would otherwise.

Basically it's something that should have been fixed early in the life
of the 8086, but wasn't, and intel's been backwards compatible every
since.

In any case with gcc targetting the SSE directly this allows for
improved floating point performance without all the baggage.