2 bit saturated branch predictor with BHR for NYU ECE GY 6193 Lab 2 Assignment

1. g++ predictor.cpp

2. ./a.out config.txt trace.txt

Check the values in trace.out.txt

Simulate a correlating branch predictor that makes use of 2-bit saturating counters. A text file containing a trace of branch instructions consisting of the PC at which each branch occurs, and whether the branch is Taken or Not Taken. Write code to evaluate the performance of a correlating branch predictor on this trace. Your output file indicates, for each branch in the trace, whether it was predicted as Taken or Not Taken.

Your design must consist of 2^m+k 2-bit saturating counters indexed using m LSBs of each branch instruction and a k bit Branch History Register (BHR) that records the outcomes of the previous k branches. Each 2-bit saturating predictor starts in the 11 (Predict Taken with High Confidence) state and is updated as per the finite state machine discussed in Lecture 12. Further, you can assume that the BHR is initialized assuming the previous k branches were Taken.
The values of m and k are specified in a config file config.txt. The maximum values of m = 20 and k = 8.

The config file config.txt contains a single line with the value of m and k. A sample file for m=12 and k=2 is provided.

The trace file, trace.txt, contains one branch per line. Each line has the PC for the corresponding branch (in hex format) followed by a single bit indicating Taken (1) or Not Taken (0). A sample trace file is provided. A sample trace file is provided.

The output from your simulator should be a file trace.out that has one line per branch. Each line has a single bit which indicates whether that branch was predicted as Taken (1) or Not Taken (0).