[RC5] finishing up an RC5 core using MMX
Jason Stratos Papadopoulos
jasonp at Glue.umd.edu
Sun Jul 26 17:29:59 EDT 1998
Hello. <Deep breath> On the off chance that an RC5 core using MMX is
still an open problem, I'm almost finished writing one, and would be
happy to make it available upon completion, along with documentation.
The finished version will require approximately 470 cycles to test a
single key, for a net keyrate of about 430 kkeys/sec on a 200MHz Pentium
MMX. This comes out to about 1.57 times the average rate on the RC5
benchmark page for the same machine.
The code as written tests four keys at a time, and uses MMX instructions
almost entirely. It's very complicated, and pairs almost perfectly
(more than 399 mips on a 200MHz machine). I'm more than a little proud
A few questions though:
Can an MMX core run up the keyrate on the PII and 6x86? These
machines already seem to test far more keys than the MHz suggest,
meaning an MMX core would only speed up the Pentium.
How much of a speedup can distribute.net expect from this? I ask
mainly to inflate my ego :)
Finally, are there specific calling conventions required? Remi
Guyomarch's driver programs aren't clear on the matter. As a related
issue, what should I do to make the final product public without
Lemme know what to do...
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