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项目作者： ethanelle

项目描述 ：
A branch predictor simulator in C++ that tests 6 different types of branch predictors.
高级语言： C++
项目地址: git://github.com/ethanelle/Branch-Predictors.git
创建时间： 2018-02-27T22:03:52Z
项目社区：https://github.com/ethanelle/Branch-Predictors
开源协议：
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Branch Predictor Project

This project is a branch prediction simulator. The predictor reads a text file as a command line argument and returns the results on the command line as well as in a text file “output.txt.”

Note: This project is for reference only. Any code used must be adequately acknowleged.

Files

  • Makefile : Self-explanatory, how to use it is described below in “Running the program”
  • example_trace.txt : An included example trace to test the program, also a formatting guide if you wish to test your own traces.
  • predictors.cpp : The actual program.
  • compare.cpp : A simple script to compare the output file to an answer key.

Running the program

To run the program with the included Makefile:

To compile without running:

  1. make

To run with the included test file:

  1. make run

To run after compiling with any test file:

  1. ./predictor file.txt

To run the compare script after compiling and running:

  1. ./compare output.txt expected_output.txt

Predictors

  • Take all branches
  • Not take all branches
  • Bimodal with table and 1-bit history
    • Table entries: 16, 32, 128, 256, 512, 1024, 2048
  • Bimodal with table and saturating 2-bit history
    • Table entries: 16, 32, 128, 256, 512, 1024, 2048
  • GShare with expanding global history register
    • Register size begins at 3 bits and expands by one each loop until 11 bits.
  • Tournament (GShare and bimodal saturating)
    • GShare global history register set to 11 bits
    • Bimodal table set to 2048 entries

Each line in output represents the respective predictor results.

Improvements Ahead

I had troubles with the tournament predictor giving me the wrong answer when using the gshare helper and bimodal saturating helper. However, I got it working by writing one (very large and very space-inefficient) function that does everything the tournament predictor needs. I think I will continue to look into this issue for a brief period of time before pushing this project to the back burner, so to speak.

References