[hashcash] Re: cpu detection, disabling mmx code on non mmx cpu (Re: Re: status of hashcash version 1?)

  • From: Jonathan Morton <chromi@xxxxxxxxxxxxxxxxxxxxx>
  • To: hashcash@xxxxxxxxxxxxx
  • Date: Wed, 4 Aug 2004 17:55:57 +0100

Does it work on 486? IIRC, under Debian, we're now allowed to compile
for i486 (though I'll have to double-check). 

That, I'm not sure.  My 486s are presently without HDs or any way of
booting, and I haven't looked at the docs anytime recently.  I'm only
certain that CPUID doesn't work on a 386.

"New" Intel 486s have it, but old ones don't. I'm not sure about AMD or Cyrix 486s, but I doubt that they had it before Intel added it.

OK, that indicates we will need separate i{3,4,5}86 binaries for best performance. The MMX cores will need to be disabled in the 3/486 versions until I can get detection to tolerate lack of CPUID. This will also need testing, so it'll have to wait until I get a 486 back on it's feet. (Given that I prefer Gentoo Linux, that could literally take weeks.)

All my 486s, including the Texas Instruments one in my parents' Acorn Archimedes, are 1992-5 era, so probably "old". A further clue is that none of them are the double- or triple-clocked variety. "New" 486s are probably restricted to specialist and embedded apps.

--------------------------------------------------------------
from:     Jonathan "Chromatix" Morton
mail:     chromi@xxxxxxxxxxxxxxxxxxxxx
website:  http://www.chromatix.uklinux.net/
tagline:  The key to knowledge is not to rely on people to teach you it.


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