Patent ID: 6732276
Filing Date: 2004-05-04
Classification: G06F

Abstract:
A computer system for executing instructions having assigned guard indicators, which system comprises instruction supply circuitry, a plurality of parallel execution units for receiving respective instructions from the supply circuitry, each instruction having a respective guard indicator selected from a set of guard indicators, common to the plurality of execution units, one of said execution units including a master guard value store containing a master representation of current values for the guard indicators in said set of guard indicators, another of said execution units including a shadow guard value store containing a secondary representation of values for the guard indicators in said set, guard ownership circuitry to indicate whether said shadow guard value store owns the current value for a guard indicator, and guard value transfer circuitry operable to transfer a guard value from said master store to said another execution unit thereby enabling selection of a guard value for said another of said execution units from either the master or shadow guard value store depending on the indication of the guard ownership.