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From: beck@nrlssc.navy.mil (Jeff Becklehimer)
Subject: How to patch broken CPU?
Message-ID: <D062sI.76r@usenews.nrlssc.navy.mil>
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Organization: Naval Research Laboratory, Stennis Space Center, MS
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Date: Fri, 2 Dec 1994 04:50:39 GMT
Lines: 25
I don't know how many of you are aware of it but the older (manufactured
before oct 94) pentium chips have a broken fpu. The floating divide unit
has been found to be the culprit. For more details see the info at\
http://www.mathworks.com/Pentium/README.html. A simple program to determine
if your's is broke is
main()
{
double x, y, z;
x = 4195835;
y = 3145727;
z = x - (x/y)*y;
printf("%f\n",z);
}
A result of 256 means bad things. I am told that Intel will replace the cpu
if they believe you are likely to run across this error. I plan to call
and ask for a new cpu but I am already thinking about possible patches. Since
I know that the cpu is broke is it possible to link in the math emulation
routines for only the divide code? I realize that it would slow down all of
my code with divides but the peace of mind is worth it.
--
<A HREF="http://www7430.nrlssc.navy.mil/7430/people/beck.html"><em>Jeff Becklehimer</em></A>