Re: Linux-asm (was A patch for linux 2.1.127)

Jamie Lokier (lkd@tantalophile.demon.co.uk)
Mon, 16 Nov 1998 10:49:54 +0000

On Sun, Nov 15, 1998 at 10:50:25AM -0500, Richard B. Johnson wrote:
> On Sun, 15 Nov 1998, Riccardo Facchetti wrote:
> > #if defined(i386)
> > #include "fasti386.S"
> > #elif defined(i486)
> > #include "fasti486.S"
> > #elif defined(P5)
> > #include "fastP5.S"
> > #elif defined(P6)
> > #include "fastP6.S"
> > else
> > #include "slow.c"
> > #endif
> >
> This might be a bit extreme, but I get your point!

He forgot "fastK5.S", "fastK6.S", "fastCx586.S, "fastCx686.S",
"fastCentaur.S", "fastPII.S", "fastP5MMX.S" and "fastPIIMMX.S".

Don't forget to test them all as thoroughly as slow.c is tested now.
Did I miss any? ;-)

Seriously, I have written optimised 486 assembly that ran 100% faster
than equivalent C, only to find it ran one third of the speed of the C
on a Pentium Pro.

Perhaps the fact that new processors are optimised to run C to a great
extent is worth considering. Meanwhile, compilers continue to be taught
more about the new processors.

-- Jamie

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