Re: /proc/cpuinfo wrong for Intel 486SX-33!!
Dominik Kubla (dominik.kubla@uni-mainz.de)
Tue, 4 May 1999 07:31:18 +0200
On Mon, May 03, 1999 at 10:24:34PM -0400, Rafael Reilova wrote:
>
> IIRC, Intel introduced the cpuid instruction with the DX-100 and Pentiums,
> so a 486SX-25 is indistiguishable from any other 486 that doesn't have the
> cpuid. In fact, there is no way to tell it is an Intel even. Only 486
> Cyrixes are identified by the kernel, and that's because they put some
> DEVID registers in there from the beginning. I'm not sure about AMD's, if
> we knew for sure that only Intel's 486 didn't have cpuid we could default
> to the "GenuineIntel" string, yet I think AMD also made some 486 without
> cpuid. Anybody who knows 486 lore around?
Look at www.x86.org. There is a rather complete code base on how to
distinguish early x86 CPU's depending on what bugs and/or undocumented
features are present. The code is even capable of distingusishing between
80(1)86 and 80(1)88 by doing tricks with the prefetch queue, also that has
(at least at the moment) little pertinence in the context of running Linux.
Yours,
Dominik Kubla
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