Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!fluke!kurt
From: kurt@tc.fluke.COM (Kurt Guntheroth)
Newsgroups: comp.misc
Subject: Re: Looking for Computer Folklore
Message-ID: <7017@fluke.COM>
Date: 17 Feb 89 17:11:29 GMT
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This was not actually true of the 6800's we had.  The instruction was to be
avoided, because nothing short of cycling power would stop it.  It cycled
the address bus through all 64k addresses very rapidly and didn't respond to
interrupts.  The effect was obvious if you had an Altair 680 (is that the
right number of zeros?  It's been awhile) as we did.  There's bunches of
folklore about unimplemented opcodes in the 6800, most of it useless.  When
I think about the 6800, I am not even convinced it is microcoded, because of
the weird ways the unimplemented opcodes worked.