Reissue logic for individually reissuing instructions trapped in a multiissue stack based computing system

摘要

An execution unit that executes multiple instructions as a single instruction group during a single processing cycle is provided. The execution unit handles problem causing instruction groups by trapping the problem causing instruction group using the trap logic of a processing unit. The reissue logic circuits restores the program state of the execution unit prior to issuance of the trapped instruction group. The reissue logic circuit then forces each instruction of the instruction group to be issued as a separate instruction. Specifically, the reissue logic inhibits folding of instructions into instruction groups by an instruction-folding unit. After the instructions of the trapped instruction group are executed, the reissue logic re-enables folding by the instruction-folding unit.