[RC5] AMD X86-64 port

Richard Menedetter ricsi at gmx.at
Sun Apr 27 22:48:52 EDT 2003


Hi Scott!

27 Apr 2003, Scott Dodson <sdodson at eagle4.cc.gasou.edu> wrote:

 >> I'm most interested to see what those extra registers in 64-bit mode
 >> can do for RC5-72 performance.
 SD> Acidblood has said that the simple fact of being 64-bit won't help,
The Athlon64/Opteron has 16 general purpose registers in 64 bit mode.
This is twice as much as a "conventional" x86 CPU.

Those 16 Registers can be addressed as 32 or 64 bit registers.

 SD> and I think he even said it would harm it.
Than you can use the Registers as 32 bit registers.
The fact that the amount has doubled should help.

 SD> But of course, if the new Opteron is overall a faster processor, it
 SD> should surely go faster.  The fact that it runs 32bit code pretty well
 SD> should be interesting too.
Opteron/Athlon64 is an athlon on sterroids.
It runs 32 bit code natively (and faster than an athlon)
and it can use 32 bit registers in 64 bit mode.

It should be pretty interesting to see how it will perform.

 SD> Scott

CU, Ricsi

-- 
|~)o _ _o  Richard Menedetter <ricsi at gmx.at> {ICQ: 7659421} (PGP)
|~\|(__\|  -=> Ever stop to think, and forget to start again? <=-
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