A Novel Approach for Branch Buffer Consuming Power Reduction

By increasing the pipeline length in processors, the accuracy of the branch predictor unit plays an important role in processors efficiencies. In addition to the accuracy, consuming power is also an essential in portable systems. Therefore, in the processors these days the prediction unit is used to determine the branch destination, while most of these accesses are not necessary. In this paper, a method is proposed to reduce the consuming power in the jump prediction unit. In this proposed method, the non-necessary accesses to BTB are reduced by taking into account this fact that there exists distances between different consecutive branch instructions. This method decides the access to BTB by a constant value and a counter. After an instruction entrance, the BTB is accessed if the counter is zero, and if the instruction is a branch instruction and exists in the BTB the counter is reset. The simulation and experimental results illustrate the suitable performance of the proposed method in comparisons to the other methods. This superiority is for both the execution time and for the consuming power. Also it is more strengthened by increasing the distance.