GrayBoy

A Game Boy emulator written in C++.

Goal

The goal of this project is to learn how to write an emulator and get to know the Game Boy architecture.

This project does not aim to produce accurate emulation, nor does it aim to present complete Game Boy emulator (there is missing sound, saves, MBC2).

This may change in the future but with the v0.1 release I consider this project to be done.

Accuracy

• All CPU instructions are implemented and all blargg individual cpu_instr tests ROMs are passing

• Blargg timing tests fail due to inaccuracies (timer/display is updated after each instruction is executed, not after each read/write operation)

• DMA transfer is instant

• Pixel processing unit is simplified

Games tested

Most games I tried run fine, if there were issues it were only minor graphics glitches.

Some examples of tested games:

Tetris

Super Mario Land

The Legend of Zelda: Link's Awakening

How to build and play on Linux

• Requires compiler with C++20 support and libsdl2-dev installed

git clone https://github.com/slaninas/grayboy/
cd grayboy && git submodule --update --init
mkdir build && cd build && make
./src/grayboy your_game

Controls

• Arrow keys, ENTER, SPACEBAR, A, S

Useful sources

• opcodes
• emudev
• codeslinger
• GbdevWiki
• BGB
• binjgb