Control device for speculative instruction execution with a branch instruction insertion, and method for same

Abstract

A device and method for implementing prediction verification control and recovery control in speculative instruction execution when a prediction error occurs with simple hardware configuration are disclosed. This device includes a branch instruction insertion unit that dynamically inserts a branch instruction subsequent to a target instruction for prediction in a group of instructions consisting of the target instruction for prediction for which a value is to be predicted and a subsequent instruction. An instruction issuing unit speculatively issues a subsequent instruction to an execution unit without waiting for the execution result of the target instruction for prediction and an execution unit executes the issued instructions. A branch prediction control unit predicts the branch destination of a branch instruction, performs branch prediction verification, and performs value prediction verification by comparing the predicted value with the execution result of the target instruction for prediction that has been executed upon execution of the inserted branch instruction.