CPU coursework 2021/2022

This repository contains code for the CPU coursework for the second-year EIE module Instruction Architectures and Compilers.

Overall design

The following diagram shows the overall design of the developed CPU.

Directories structure

• modules_tb - test benches for particular submodules of the CPU
• modules_tb - test benches for particular submodules of the CPU pipelined version of CPU
• rtl - folder that contains Verilog source files for the CPU
  • mips_cpu_bus.v - main Verilog CPU module that interconnects all submodules
  • mips_cpu/*.v - Verilog files for submodules
• rtl_interrupt - folder that contains Verilog source files for the version of the CPU that supports interrupts
  • mips_cpu_bus.v - main Verilog CPU module that interconnects all submodules
  • mips_cpu/*.v - Verilog files for submodules
• rtl_pipelined - folder that contains Verilog source files for the pipelined version of the CPU that fully supports only simple memory
  • mips_cpu_bus.v - main Verilog CPU module that interconnects all submodules
  • mips_cpu/*.v - Verilog files for submodules
• test - contains files for testing
  • bin - contains binary files that are needed to run the testing environment
  • logs - contains log files from separate module test benches
  • testbenches - template test bench files that are used as a source for all assembly programs testing
    • memories - folder with memories used by test benches
  • utils - assembler files
    • test - unit tests for assembler
  • build_utils.sh - builds utility files needed
  • clean_all.sh - cleans all files from previous testing
  • run_all_testcases.sh - runs all testcases
  • run_one_module_tb.sh - runs exactly one test bench, parameter: name of the test bench
  • run_one_testcase.sh - runs exactly one testcase, parameters: testcase name, verbose enabled/disabled, base test bench name
  • test_mips_cpu_bus.sh - runs all test cases for the submission
• CMakeLists.txt - CMake file for setting up CLion unit testing environment

Testing

All bash scripts in the test folder assume that they will be executed in the root folder of the project.

Following command runs all testcases for ADDIU instruction on the non-pipelined CPU:

./test/test_mips_cpu_bus.sh rtl addiu

To run all test cases on the non-pipelined CPU enter following command:

./test/test_mips_cpu_bus.sh rtl addiu

Assembler

In order to speed ut testing, MIPS assembler was implemented in C++. This assembler takes as an input assembly file with MIPS instructions. As an output, it then generates hex files that are loaded to RAM memory using file as a parameter in Verilog. The assembler was developed with a use of test driven development. Unit tests can be found in test/utils/test. The test cases are written in Google Test and the whole C++ environment was set up using CMake. Due to the fact that MIPS programs start at 0xBFC00000, all data address are automatically aligned by offset of 0xBFC00000. The nop instruction in the assembler can be written as NOP.

Authors

• Michal Palič
• Vaclav Pavlíček
• Pablo Romo Gonzalez
• Arthika Sivathasan
• Henry Hausamann
• Yusuf Salim