Path: utzoo!attcan!utgpu!news-server.csri.toronto.edu!rutgers!usc!samsung!munnari.oz.au!mullian!raob
From: raob@mullian.ee.mu.oz.au (richard oxbrow)
Newsgroups: comp.arch
Subject: Re: 486 bugs -- it's in there!
Message-ID: <4250@munnari.oz.au>
Date: 26 May 90 15:38:40 GMT
References: <634@sibyl.eleceng.ua.OZ> <76700202@p.cs.uiuc.edu> <350@necssd.NEC.COM> <2813@medusa.informatik.uni-erlangen.de>
Sender: news@cs.mu.oz.au
Reply-To: raob@mullian.ee.mu.OZ.AU (richard oxbrow)
Organization: Dept. of Electrical Engineering, University of Melbourne
Lines: 38

In article <2813@medusa.informatik.uni-erlangen.de> csbrod@medusa.informatik.uni-erlangen.de (Claus Brod ) writes:
>harrison@necssd.NEC.COM (Mark Harrison) writes:
>>> microprocessor revelations, '286, '386 (2, right?), and now I wonder
>>> -- will there be a bug in the '486?
>
>>You've already lost.  There was a bug when a trig function followed
>>a sequence of integer instructions.  Does anybody still have a copy
>>of the article that described this?  Is Intel unique in having bugs
>>in their newly released chips?
>

IEEE Spectrum, April 1990 (pages 10-11) gives a short article about Intel's
problems with the i486.  In addition to the trig bug (see above) which Compaq
Computer Corp. (Houston TX) found, another bug was found in a prototype
EISA bus setup. In this case a 

	"A particular sequence of bus instructions from the i486 would
trigger the error, causing a prototype
extended-industry-standard-architecture (EISA) chip to hang up. The problem
would not occur in products using other architectures, such as the ISA, or
in the products using the production EISA chip."

(Extracted from the afore mentioned IEEE article)

The article is worth a quick look (they claim other bugs have been found
and how the EISA problem found its way into the papers)

	richard ..

#ps Does anyone want to shed some light on the stories about manufacture of
the VIPER cpu (UK) <The viper cpu was designed to be mathematically-logically
 correct>,  but did all the prototypes work ? ;-)
And while we are on it what about some of the (mil) 1750 A chips ! or
whatever the americans put in their cruise missiles.
richard oxbrow			   |
ee eng,  uni of melbourne          |Internet	raob@mullian.ee.mu.OZ.AU
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