prateekbashista / branch-prediction-simulator

Branch Direction Simulator using C++ and Build Environment using Makefile

Branch Prediction Simulator

This project implements a branch direction predictor that is used in CPU designs to predict the taken or not-taken behaviour of the branch. The simulator is capable of simulating 2bc Saturing Counter Predictor, 1-bit Bimodal Predictor and Gshare Branch History Predictor.

The simulator uses unordered maps data structure in C++ to mimic the cache behaviour and provides O(1) search times.

The simulator tests the branch prediction implementation against 3 workloads: test_br.ctrace, house.ctrace, wireframe.ctrace using the custom feeder program which reads the aforementioned files, extracts the PC, read the instruction and decides if the PC is a branch or not, and feeds the data to predictors.

Since, my simulator knows if the PC is a branch or not, the predictor in the original CPU hardware will sit at the decode stage. Additionally, predictors can be simulated in future by adding BTB and whether it's a branch or not to the program.

Steps to run the Simulator

The Makefile has commands for all three simulators with each having backward compatibility, so 2bc compiles bimodal as well and gshare compiles everything.

1. Clean Command

make CleanGshare

2. Compile Command

make gshare

3. Output Command

./gshare > output.txt