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SubjectRe: MMX emulator ?
On Tue, 16 Jun 1998, Jeffrey Hundstad wrote:

> > i = detect_MMMX();
> > if !i then usenormalstuff=1;
> > else usemmx=1;

> If you can assume the MMX functions are there then EACH application
> doesn't have to emulate all of the MMX stuff itself if it doesn't have
> the REAL hardware.

> This should be treated EXACTLY like the Floating Point hardware... at
> least in my opinion.

The 'normal stuff' in a real application that cared about
decent speed would NOT be emulating the MMX instructions, but
would do things differently. MMX is all about speed. I'd
expect emulated MMX to be far slower than writing the code
optimally using the instruction set available on a non-MMX
CPU. And this is not counting the overhead from trapping the
MMX opcodes.

If writing an MMX emulator leads to application programmers
being lazy and just doing MMX versions of their apps, because
"MMX is always available on Linux", then you have made a great
disservice to the users.

Johan Myreen

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