Pshare:A Two-Level Adaptive Branch Predictor Algorithm and Its Implementation

A branch prediction algorithm and predictor called Pshare is proposed,which has the benefit of PAs and the Gshare predictor,and modifies their flaws due to using a global history pattern by using a separate branch history shift register(BHSR).Moreover it also can reduce the area and delay overhead than PAs by accessing a small PHT table using the hash of address and history patterns instead of accessing two dimensions PHT table using the address and history patterns.The Pshare predictor can obtain the branch prediction accuracy of PAs,but the implementation overhead is near to Gshare.This predictor is applied to high performance processors which have a superscalar deep pipeline and focuses more on higher core performance.It reduces the pipeline's vertical waste and improves the core performance and efficiency by using the Pshare predictor.