Dynamic branch predictor indexing a plurality of weight tables by instruction address fetch history and making a prediction based on a product sum calculation of global history register values and outputted weight table value

Abstract

A processor includes: an instruction execution unit that executes an instruction; and a branch prediction unit that stores history information indicating every instruction fetches performed a certain number of times before an instruction fetch of a branch prediction target instruction whether the instruction predicted as branch-taken is included and weight tables including weights corresponding to instructions and predicts the branch prediction target instruction to be taken or not-taken. The branch prediction unit, before the instruction fetch of the branch prediction target instruction, obtains the history information and the weights related to the instruction fetches performed the certain number of times to perform a product-sum operation, and at the time of the instruction fetch of the branch prediction target instruction, performs an operation of a result of the product-sum operation and a weight of the branch prediction target instruction to perform branch prediction.