Cessor> (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 Motorola6800miCroproCessor 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. [Confirm?] (1995-12-14)