Branch predictor design and performance estimation for a high performance embedded microprocessor

摘要

The AE64000 is a 64 bit embedded processor targeting high-end embedded applications such as HDTV, DVD, and 3D graphics. To achieve a higher performance for the AE64000, we design a branch predictor for the processor, and find the optimum parameters for the design through cycle-accurate simulations on SpecINT benchmarks and embedded applications (Dhrystone and Whetstone). In the AE64000, branch prediction is complicated by the instruction folding unit (IFU) of the processor front-end. By predicting on a pre-PC in the IFU, rather than using a PC in the pipeline core, we can effectively eliminate the branch misprediction penalty on a correct prediction. We have developed the AE64000 simulator to evaluate the performance of the designed branch predictor, and selected the optimum branch predictor configuration by considering cost-effectiveness as well as by analyzing the results generated from the AE64000 simulator. The selected branch predictor has been implemented in Verilog and is added to AE64000 pipeline.