Path: utzoo!attcan!lsuc!ncrcan!brian
From: brian@ncrcan.Toronto.NCR.COM (Brian Onn)
Newsgroups: comp.arch
Subject: Re: amusing opcodes
Message-ID: <878@ncrcan.Toronto.NCR.COM>
Date: 18 Aug 88 00:56:48 GMT
References: <5458@ecsvax.uncecs.edu> <1876@looking.UUCP> <753@applix.UUCP> <3884@sequent.UUCP> <719@mcrware.UUCP> <5440@june.cs.washington.edu> <1988Aug7.013526.7798@utzoo.uucp> <217@mango.athertn.Atherton.COM>
Reply-To: brian@ncrcan.Toronto.NCR.COM (The Super User)
Organization: NCR Canada Ltd., Mississauga, Ontario
Lines: 22

In article <217@mango.athertn.Atherton.COM> ericb@mango.UUCP (Eric Black) writes:
>In article <1988Aug7.013526.7798@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes:
>>As is now moderately well-known, some of the Motorola 8-bit chips actually
>>have such an instruction, sort of:  there is a test opcode which makes the
>>CPU just sit there endlessly incrementing its address lines.  Nothing short
>>of powerdown will shake it out of this.  Some third-party opcode charts
>>show this as HCF.  The Motorola spec sheet that I remember doesn't give it
>>a name, but does have a footnote warning you about it.
>
>Actually, it's better called WTD -- "Walk The Dog".  On the 6800 it...

Is'nt this (HCF) an acronym for Halt and Catch Fire?.  I remember seeing
it described as just that in one of those third party opcode charts.

:-)

Brian.

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