BRANCH PREDICTING DEVICE USING BRANCH PREDICTION PRECISION HISTORY

摘要

PROBLEM TO BE SOLVED: To provide a device capable of reducing failures in branch prediction with simple circuit structure and at low hardware cost in a 2-level branch predicting device of a CPU. SOLUTION: This branch predicting device includes a branch predicting means and a precision history table to store the precision of an inspection result of a predicting condition predicted from the branch predicting device. The inspection result of the predicting condition generated by the branching predicting means is not immediately used and the inspection result of the predicting condition based on the branch predicting precision history is used as the last predicted value of branch by the branch predicting device. As a result, the failures in branch prediction to be generated in the case of 2-level branch prediction are reduced and more efficient execution of an instruction of the CPU is provided.