shinobu (しのぶ)

"Well, I'm sorry. You haven't even realized that people don't like you, then?" - Kochō Shinobu

Demon Slayer: Kimetsu no Yaiba, by Koyoharu Gotōge

shinobu (しのぶ) is a cycle accurate Game Boy (1989) and Game Boy Color (1998) debugger, disassembler and emulator written in modern C++.

Pokémon Gold Version - Game Boy Color (1999)	Metroid II: Return of Samus - Game Boy (1992)

Building

This project can be built in Linux or Windows (with MSYS2) with SLD2 using either GCC 9.3.0 and Make or Clang 10.0.1 and Ninja.

$ cmake -Bbuild # On Windows with MSYS2: `-G 'MSYS Makefiles'` or `-GNinja`
$ cmake --build build --parallel # Or `ninja -C build`

Usage

$ shinobu -h
Usage: shinobu [-s] [-d] [-h] filepath

  -s   skip BOOT ROM, only supported by DMG emulation
  -d   disassemble, a `filepath.s` file will be created
  -h   print this message

A bootstrap ROM can be optionally (required for CGB emulation) placed in the current path:

DMG_ROM.BIN (SHA1: 4ed31ec6b0b175bb109c0eb5fd3d193da823339f)
CGB_ROM.BIN (SHA1: 1293d68bf9643bc4f36954c1e80e38f39864528d)

A shinobu.yaml file will be generated to further configure the emulator options:

audio:
  mute: false
emulation:
  CGBBootstrapROM: CGB_ROM.BIN # Relative path to CGB bootstrap ROM file, required
  DMGBootstrapROM: DMG_ROM.BIN # Relative path to DMG bootstrap ROM file, optional
  colorCorrection: true # Enable color correction
  overrideCGB: false # Use DMG emulation whenever possible
frontend:
  kind: SDL # Default: SDL, Available: PPU (show VRAM state)
input:
  controllerName: Bluetooth # For non-Xbox-like controllers only
log: # Logging configuration (log levels: NOLOG, MSG, WAR)
  CPU: NOLOG
  DMA: NOLOG
  PPU: NOLOG
  ROM: NOLOG
  disassembler: NOLOG
  interrupt: NOLOG
  joypad: NOLOG
  memory: NOLOG
  openGL: NOLOG
  serial: NOLOG
  sound: NOLOG
  timer: NOLOG
video:
  fullscreen: false # Desktop fullscreen startup
  integerScale: false # Enable to force integer scaling, helps with shaders on high density displays
  overlayScale: 0 # Enable overlay with 1 and increase this if it's is too small
  palette: 0 # Select a custom palette for DMG emulation (10 available)
  screenDoorEffect: false # Emulate Game Boy LCD screen door effect

Keybindings

Gamepad support is implemented by SDL_GameController API (Xbox-type controllers) and SDL_Joystick API (other type of controllers) with static bindings. Only the Game Boy buttons and DMG palette selection are mapped.

PPU visualizer

Known issues

Scanline rendering: the PPU emulation is driven by a scanline renderer, LCD timing effects are not working and games like Prehistorik Man won't run correctly.
Cartridge supported: MBC1 (RAM+BATTERY), MBC3 (RAM+BATTERY+TIMER), MBC5 (RAM+BATTERY), everything else won't run at all.
Game Boy Color emulation requires a bootstrap ROM.

Acknowledgments

This emulator, like many others, has it's implementation based on the Pan Docs Game Boy technical reference, a compilation of the work of many people. I also got a lot of questions answered by the emulator development community at emudev.org.