> 6502s have this opcode as well - and on some 6502s it really can
> destroy
> the CPU. (or so I've heard anyway...) It does something similar to the
> 6800's - toggling bus lines - so it may be that this is true for the
> 6800 as well.
>
From and old copy of "The New Hacker's Dictionary":
HCF /H-C-F/ n. Mnemonic for 'Halt and Catch Fire', any of several
undocumented and semi-mythical machine instructions with destructive
side-effects, supposedly included for test purposes on several
well-known architectures going as far back as the IBM 360. The MC6800
microprocessor was the first for which the HCF opcode became widely
known. This instruction caused the processor to toggle a subset of the
bus lines as rapidly as it could; in some configurations this can
actually cause lines to burn up.
-Clay
Received on Tue Apr 14 17:08:12 1998
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