Processor and method for speculatively executing a conditional branch instruction utilizing a selected one of multiple branch prediction methodologies

摘要

A processor (10) and method for speculatively executing branch instructions utilizing a selected branch prediction methodology are disclosed. The processor has one or more execution units (22, 28, 30) for executing instructions, including a branch processing unit (18) for executing branch instructions. The branch processing unit includes selection logic for selecting one of a plurality of branch prediction methodologies and a branch prediction unit for predicting the resolution of a conditional branch instruction utilizing the selected branch prediction methodology. The branch processing unit further includes execution facilities for speculatively executing the conditional branch instruction based upon the prediction. Based upon the outcome of the prediction, the selection logic selects a branch prediction methodology for predicting a subsequent conditional branch instruction so that branch prediction accuracy is enhanced. In one embodiment, the multiple branch prediction methodologies include static and dynamic branch prediction.