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

  • From: "Hamilton, Michael" <mhamilton@xxxxxxx>
  • To: <hashcash@xxxxxxxxxxxxx>
  • Date: Wed, 4 Aug 2004 09:17:55 -0700


> > Jonathan> Yes, that's correct.  The detection code relies on the CPUID
> > Jonathan> instruction being present (which is why it'll probably break
> > Jonathan> nastily on old CPUs like the 386), but it can in turn be
> > Jonathan> short-circuited out by compiling without MMX support.
> >
> > 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.

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