Halt and Catch Fire


Halt and Catch Fire

(humour, processor)(HCF) Any of several undocumented andsemi-mythical machine instructions with destructiveside-effects, supposedly included for test purposes on severalwell-known architectures going as far back as the IBM 360.The Motorola 6800 microprocessor was the first for whichan HCF opcode became widely known. This instruction causedthe processor to toggle a subset of the bus lines asrapidly as it could; in some configurations this couldactually cause lines to burn up.