[rc5] Client optimizations

Marc Sissom msissom at dnaent.com
Tue Jul 29 15:11:43 EDT 1997

At 11:58 AM 7/29/97 -0700, you wrote:
>Murray Stokely wrote:
>> % Is this correct?  Is anyone considering 6x86MX and K6 optimizations?

No one has(yet) discovered any rc5/MMX optimizations that are worthwhile.

>> % It seems like the K6's are really slow for their clock speed.  Can
>> % anyone confirm whether or not they have a rotate instruction?  It
>> has
>> % been speculated that they might not, but no one was able to
>> % confirm/deny this with authority.  Just curious, especially about
>> the
>> % 6x86MX optimization.  Besides better branch prediction and a larger
>> % (64k) L1 cache, is it that much different from the 6x86?.


>> Of course they have a rotate instruction.  it is an x86 chip, therefor
>> it can execute all the x86 instructions.

Indeed, so is my x86 simulator that I use for debugging, and it can
execute the x86 instructions; but it does not have a native,
multi-bit-variable-on-register-rotate implemented in hardware, and
so it does it slowly.

>But it is certainly possable that the decoder could accept the
>instruction only to convert it into a series of other "native"

Which is, of course, what it does.

To unsubscribe, send email to majordomo at llamas.net with 'unsubscribe rc5' in the body.

More information about the rc5 mailing list