gogo-gb#

a gameboy (color) emulator for funsies

Current status#

• Games are playable.
• CPU cycle accuracy, but memory timings not correct.
• Scanline rendering, so some games/homebrew using mid-scanline effects may look funky/broken.
  • This most visibly affects color games changing palettes mid-scanline.
• No audio.

Usage#

$ gogo-gb --help
gogo-gb is a scrappy Game Boy emulator written in the Go programming language.

This is a side-project for fun with indeterminate goals and not a stable emulator.

Usage:
  gogo-gb [command]

Available Commands:
  completion  Generate the autocompletion script for the specified shell
  help        Help about any command
  inspect     Inspect cartridges, emulator internals, etc.
  run         Run a cartridge

Flags:
  -h, --help         help for gogo-gb
      --log string   Path to log file. Default/empty implies stdout

Use "gogo-gb [command] --help" for more information about a command.

TODO#

• Pass all of Blargg's cpu_instrs ROMs (verified via gameboy-doctor)
• Implement MBC1
• Implement MBC2
• Implement MBC5
• Implement MBC3 (w/o RTC)
• Implement serial port (w/ option to log to console)
• Implement timer
• Pass Blargg's instr_timing.gb ROM (manually verified)
• Implement a basic interactive debugger
• Implement LCD
• Implement (scanline) PPU, VRAM, OAM, etc.
• Implement Joypad
• Implement SRAM save & restore
• Implement watch in debugger for memory & register changes
• Implement RTC for MBC3
• Pass dmg-acid2 test ROM
• Pass cgb-acid2 test ROM
• Implement GBC
• FIFO-based rendering PPU (currently scanline)
• Implement PPU registers debugging
• Implement Sound/APU

Later/Maybe Never?#

Just being realistic about my likelihood of getting to these:

• Pass Blargg's mem_timing ROMs (manually verified)
• Pass Blargg's mem_timing-2 ROMs (manually verified)
• Implement emulation for every known DMG bug
• Implement SGB mode
• Implement MBC6
• Implement MBC7
• Implement MBC1M, MMM01, other multicarts, or Hudson carts
• Implement (any) accessories

Inspiration Material#

• DMG-01
• Gameboy Doctor
• Let's Write a Gameboy Emulator in Python
• Pandocs
• Writing a Gameboy Emulator in Rust