SSor> (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)