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Newsgroups: comp.os.386bsd.questions Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!yarrina.connect.com.au!werple.apana.org.au!otis.apana.org.au!serval.net.wsu.edu!netnews.nwnet.net!oracle.pnl.gov!osi-east2.es.net!cronkite.nersc.gov!dancer.ca.sandia.gov!overload.lbl.gov!lll-winken.llnl.gov!ames!tulane!darwin.sura.net!usenews!beck From: beck@nrlssc.navy.mil (Jeff Becklehimer) Subject: How to patch broken CPU? Message-ID: <D062sI.76r@usenews.nrlssc.navy.mil> Sender: news@usenews.nrlssc.navy.mil Nntp-Posting-Host: abyss.nrlssc.navy.mil Organization: Naval Research Laboratory, Stennis Space Center, MS X-Newsreader: TIN [version 1.2 PL2] 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>