H-GBC

An emulator for the Nintendo Gameboy Color in Haskell because -- why not?

Work in progress!

Passes all relevant parts of the Blargg test suite (cpu_instrs, instr_timing, interrupt_time, mem_timing, mem_timing-2, cgb_sound, and halt_bug). Does not pass dmg_sound or oam_bug since H-GBC emulates the Gameboy Color, and the Gameboy Color hardware does not pass those tests.

Also passes most of the relevant parts of the Mooneye GB suite, with the notable exception of the PPU tests. H-GBC's graphics code works reasonably well, but it is not cycle-accurate. There may be some glitches or other differences from the original hardware.

The latest test report is at https://hgbc-test-results.netlify.app/ .

Build

1. Install Haskell Stack from https://docs.haskellstack.org/en/stable/README/

2. Install dependencies

sudo apt install libsdl2-dev

3. Build with

stack build

Run

Make executables available on your PATH with:

stack install

Run the SDL frontend with:

hgbc-sdl <rom file>

For a list of command line options:

hgbc-sdl --help

After the first run, there will be a configuration ~/.hgbc/config.toml where default options can be set globally. This file also allows the user to change the key bindings and colour palettes for monochrome ROMs.

For ROMs with backing RAM, RTC, or other state that needs to be saved between sessions, that state is saved in the directory ~/.hgbc/<rom_file_name>/ where <rom_file_name> is the name of the ROM file. It is also possible to put a config.toml file in the ~/.hgbc/<rom_file_name> directory to set default options for a ROM. ROM specific configuration files have the same format as the global configuration file.

Debugger

To debug a ROM file, launch H-GBC with the --debug flag. Then open a web browser at localhost:8080. The port number can be changed by a command line option (--debug-port) or in ~/.hgbc/config.toml.