< humour , processor > (HCF) 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 Motorola 6800 microprocessor was the first for which an 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 could actually cause lines to burn up.
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(1995-12-14)