Teisybe's Chip8-cpp Interpreter

Apparently, in order to start writing any decent emulators, one has to first participate in a rite of passage and write a simple Chip 8 interpreter, that is then sacrificed to the emulator gods. You can consider this project my contribution to the aforementioned rite of passage. <sarcasm>Being an original dude, I chose C++ and SDL to implement this interpreter, surely nobody has done this before.</sarcasm>

Features

• Full original Chip 8 implementation
• Uses completely software audio pipeline
• Simple and concise single threaded implementation (SDL2 may spawn an additional thread for audio)
• Adjustable execution speed
• Adjustable screen scaling, which preserves the original aspect ratio
• Unit tests for core components of the interpreter

Usage

Chip8-cpp interpreter does not have a graphical user interface, so all interactions with the application happen via terminal (or command line, for you Windows peeps).

First of all, to get usage instructions, run ./chip8-cpp --help. A helpful information screen will be presented to you with all the available options.

To load an run a Chip 8 rom, use ./chip8-cpp -r <path to .ch8 file>.

To change execution speed, use -f <speed> option (default is 500 instructions per second).

To change scale, use --upscale-mult <multiplier> option (default is original Chip 8 resolution multiplied by 20). Extremely high multipliers may negatively impact performance.

Building

This project utilizes CMake to generate build files for your desired compiler. Currently, only Linux builds with GCC have been tested.

During build process, CMake also downloads additional dependencies: cxxopts for command line option parsing and doctest for unit tests (if testing is enabled).

If unit testing is desired, use an additional -DBUILD_TESTS=On flag for CMake.

GNU/Linux

Requirements (can be acquired from the package manager of your selected distro):

• Cmake 3.15+
• gcc 11.1+
• SDL 2

Build instructions:

git clone git@github.com:TeisybeLT/chip8-cpp.git
cd chip8-cpp
mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE=Release
make

The resulting binary will be placed in build/bin directory.

Future plans

Currently, my implementation of Chip 8 interpreter does everything I initially set out to do. Mainly - execute Chip 8 code. But in the future, if I regain my interest in this project, here's what I will do:

• Proper versioning system
• Proper full screen support and other scaling types
• Windows, OSX and Web Assembly build targets
• CI/CD integration with proper packaging and automated static analysis tool support
• Super Chip 8 support
• A small launcher GUI, so users don't have to muck around in terminal
• Disassembler
• Debugger