cvs commit: src/sys/dev/random probe.c

Ian Dowse iedowse at maths.tcd.ie
Mon Feb 7 10:23:38 PST 2005


In message <200502071015.39224.jhb at FreeBSD.org>, John Baldwin writes:
>On Sunday 06 February 2005 11:55 am, Ian Dowse wrote:
>>   Check that we have at least a 586-class CPU before calling do_cpuid().
>>   This fixes booting on a number of 486 processors.
>
>This is wrong.  Some 486's do have cpuid, notable the dx4's (I used to have 
>one.)  The correct test is to see if you can flip a bit in %eflags (can't 
>remember which one).  If that flag stays at zero then you don't have cpuid, 
>if the bit follows the value written to it then you do have cpuid.

Indeed - it's just a quick workaround that I'll fix when you find
me a 486 with a Nehemiah random number generator ;-)

Ian


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