Gemu

Gemu is a neat little Game Boy emulator written in C as a personal exercise to learn the language.

Name idea blatantly stolen inspired by QEMU.

Building

If you have Nix, you already know what to do.

Otherwise, you'll need the following dependencies:

• Meson
• One of SDL3, Raylib, OpenGL + GLUT, SFML.

If you don't specify -Dtests=false when running meson setup, you'll also need:

• Unity Test
• cJSON
• Ruby (for running some build scripts)

You can clone, compile and run the project with these commands:

git clone https://codeberg.org/Grazen0/gemu
cd gemu
meson setup build -Dfrontend=sdl3 # One of sdl3, raylib, opengl, sfml. Defaults to "sdl3".
meson compile -C build
build/gemu path/to/rom.gb

Note that you can choose the frontend (sdl3, raylib, opengl, or sfml) with -Dfrontend.

Progress

Note

Gemu does not support any mappers as of now, so only games with no mapper (like Tetris) will work.

• CPU emulation
• Custom boot ROM support
• Graphics
  • Background tiles
  • Objects
  • Window drawing
  • Scrolling
  • Proper OAM transfer timing
• Timers
• Mappers
  • MBC1
  • MBC2
  • MBC3
  • MBC4
  • MBC5
  • MBC6
  • MBC7
  • MMM01
  • M161
  • HuC1
  • HuC-3
  • Other (?)
• Interrupts
  • VBlank
  • STAT
  • Timer
  • Serial
  • Joypad
• Serial transfer
• Audio
• CGB support
• Gamepad support (via SDL)

Credits

• Raddad772's sm83 instruction tests, which are used in this project.
• gbdev.io and the Pan Docs for their incredible help.