| 摘要 |
PROBLEM TO BE SOLVED: To estimate the reliability of branch prediction with high accuracy. SOLUTION: The branch prediction reliability estimation circuit in a processor includes: an instruction processing pipeline 30 for performing pipeline processing of an input program; a branch predictor 40 for predicting a branch direction of a conditional branch instruction included in the program; and a pipeline gating circuit 20 for determining whether to permit speculation processing execution of an instruction in accordance with a prediction reliability to the conditional branch instruction. The branch prediction reliability estimation circuit is provided with: a reliability determining means for determining the reliability of the prediction from the prediction reliability to the conditional branch instruction; a reliability updating means for updating the reliability of the prediction to the conditional branch instruction; and an allowable threshold storage circuit 12 for storing an allowable threshold to be used to determine the reliability. The reliability determining means compares the allowable threshold input from the allowable threshold storage circuit 12 with the reliability to determine the reliability. COPYRIGHT: (C)2010,JPO&INPIT |
