[RC5] Re: rc5-digest V1 #253

Mike Silbersack silby at silby.com
Sun Jan 10 18:07:00 EST 1999

On Sun, 10 Jan 1999 11:20:54 -0500, Brice D. Fleckenstein wrote:

>> Our bitslicer can check more than 1,000,000 keys per second on most
>> recent processors.
> More precisely, *ANY* Intel MMX CPU will do well over 1,200,000
>keys/sec on DES with the current MMX code - the *slowest* of those CPUs
>is the Pentium-166MMX, and my machine with that CPU pulls almost exactly
>1,300,000 under Win95 (would be faster under almost any other supported
>OS, but that's my game machine and the only one that NEEDS MMX for
>anything else).
> It's too bad the MMX code runs so much SLOWER than non-MMX code on
>every other MMX-compatable CPU to date.

Heh.  Too bad that's a totally incorrect statement too.

For RC5, the mmx code only runs decently on the Pentium MMX processor;
all other processors, including the Pentium 2, run it terribly.

For DES, the mmx code runs faster than integer code on *every* mmx
capable processor than the comparable integer code.  If I recall
correctly, the fastest (pre mhz) des mmx processors are the Pentium
MMX, then the K6-2, then the Pentium 2.

Mike "Silby" Silbersack
silby at silby.com
distributed.net Technical Support / Programming

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