GB-EM

A Gameboy Classic and Gameboy Color emulator written in Rust

Building

1. Clone the repository into your desired directory
2. Change to the project directory
3. You can either run the shell script using ./run.sh or run cargo build --release
4. Running the emulator can be done by cargo run --release or by changing directory to target/release.
5. You can add this binary to ~/.local/bin/ in linux or PATH in windows.
6. You can run test roms and sample games added in /test-roms. You can run any .gb and .gbc roms on this emulator. (Note: Make sure to extract the ROMs before running).

Then you can explore the ability of the emulator by gb_em --help. Which outputs

A Gameboy Colour emulator written in Rust

Usage: eb_em [OPTIONS] <filename>

Arguments:
  <filename>  Sets the ROM file to load

Options:
  -s, --serial         Prints the data from the serial port to stdout
  -p, --printer        Emulates a gameboy printer
  -c, --classic        Forces the emulator to run in classic Gameboy mode
  -x, --scale <scale>  Sets the scale of the interface. Default: 2
  -a, --audio          Enables audio
      --skip-checksum  Skips verification of the cartridge checksum
      --test-mode      Starts the emulator in a special test mode
  -h, --help           Print help
  -V, --version        Print version

Now you can look below for the Keybindings section below.

Keybindings

Gameplay Keybindings

Key on Keyboard	Emulator Key
Z	A
X	B
Up/Down/Left/Right	Up/Down/Left/Right
Space	Select
Return/Enter	Start

General Keybindings

Key on Keyboard	Emulator Action
1	Switch to 1:1 scale
R	Restore scale given on command line
Left Shift (Hold)	Unrestricted Speed Mode
T	Change pixel interpolation

Implemented

• CPU
  • All instructions correct
  • All timings correct
  • Double speed mode
• GPU
  • Normal mode
  • Color mode
• Keypad
• Timer
• Audio
• MMU
  • MBC-less
  • MBC1
  • MBC3 (with RTC)
  • MBC5
  • save games
• Printing

Future scope

• GameBoy Advance support
• Making the emulator cycle-accurate
• Adding better support for sound
• Adding UI support for ROM opening
• Game save and reload

Test mode

The test mode, activated with the --test-mode flag, provides some functionality for running GBEmulatorShootout. This is still under development.

Special thanks to

• http://imrannazar.com/GameBoy-Emulation-in-JavaScript:-The-CPU
• http://bgb.bircd.org/pandocs.htm
• https://github.com/alexcrichton/jba (The Rust branch)
• https://gbdev.io/pandocs/