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Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: comp.arch
Subject: Re: Speed is the one true performance metric
Message-ID: <7326@utzoo.UUCP>
Date: Mon, 17-Nov-86 13:13:08 EST
Article-I.D.: utzoo.7326
Posted: Mon Nov 17 13:13:08 1986
Date-Received: Mon, 17-Nov-86 13:13:08 EST
References: <340@euroies.UUCP>
Organization: U of Toronto Zoology
Lines: 17

> CORRELARY: I bet the same thing happens soon (if it hasn't already) inside
> 	   somebody's fancy new CPU chips...

Arguably it has.  For quite a while the 32032 had an obscure (although
documented) bug reminiscent of your examples.  If I recall correctly, the
problem was that if a lot of the high bits in the stack pointer were 1s,
and an increment caused a carry to go up all the way and turn a lot of
those bits to 0s all at once, the increment gave the wrong result.  My
guess would be that the pattern-sensitivity indicates an analog electrical
problem rather than a logic error.

(I can't be sure I've got the details right, since I threw out my 32032
bug lists when I finally concluded that I was never going to use the chip
and didn't care about it any more, but it was something along those lines.)
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,decvax,pyramid}!utzoo!henry