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Nintendo - Game Boy / Color (Gearboy)

Background

Gearboy is an open source, multi-platform, Nintendo Game Boy (DMG) / Game Boy Color (CGB) emulator written in C++.

  • Highly accurate CPU emulation, passes cpu_instrs.gb from blargg's tests.
  • Accurate instruction and memory timing, passes instr_timing.gb and mem_timing.gb from blargg's tests.
  • Memory Bank Controllers (MBC1, MBC2, MBC3 with RTC, MBC5), ROM + RAM and multicart cartridges.
  • Accurate LCD controller emulation. Background, window and sprites, with correct timings and priorities including mid-scanline timing.
  • Mix frames: Mimics the LCD ghosting effect seen in the original Game Boy.
  • Sound emulation using SDL Audio and Gb_Snd_Emu library.
  • Battery powered RAM save support.
  • Save states.
  • Game Genie and GameShark cheat support.
  • Runs on Windows, Linux, Mac OS X, Raspberry Pi, iOS and as a libretro core (RetroArch).

The Gearboy core has been authored by

  • Ignacio Sanchez

The Gearboy core is licensed under

A summary of the licenses behind RetroArch and its cores can be found here.

BIOS

Not required.

Extensions

Content that can be loaded by the Gearboy core have the following file extensions:

  • .gb
  • .dmg
  • .gbc
  • .cgb
  • .sgb

RetroArch database(s) that are associated with the Gearboy core:

Features

Frontend-level settings or features that the Gearboy core respects.

Feature Supported
Restart ✔
Screenshots ✔
Saves ✔
States ✔
Rewind ✔
Netplay ✕
Core Options ✔
RetroAchievements ✔
RetroArch Cheats - Game Genie ✔
RetroArch Cheats - GameShark ✔
Native Cheats ✕
Controls ✔
Remapping ✔
Multi-Mouse ✕
Rumble ✕
Sensors ✕
Camera ✕
Location ✕
Subsystem ✕
Softpatching ✔
Disk Control ✕
Username ✕
Language ✕
Crop Overscan ✕
LEDs ✕

Directories

The Gearboy core's library name is 'Gearboy'

The Gearboy core saves/loads to/from these directories.

Frontend's Save directory

File Description
*.srm Cartridge battery save
*.rtc Real time clock save

Frontend's State directory

File Description
*.state# State

Geometry and timing

  • The Gearboy core's core provided FPS is 59.7275005696
  • The Gearboy core's core provided sample rate is 44100 Hz
  • The Gearboy core's base width is 160
  • The Gearboy core's base height is 144
  • The Gearboy core's max width is 160
  • The Gearboy core's max height is 144
  • The Gearboy core's core provided aspect ratio is 10/9

Core options

The Gearboy core has the following option(s) that can be tweaked from the core options menu. The default setting is bolded.

Settings with (Restart) means that core has to be closed for the new setting to be applied on next launch.

  • Emulated Model (restart) [gearboy_model] (Auto|Game Boy DMG)

    Select which hardware/model is emulated.

    • Auto selects the best hardware based in the rom.
    • Game Boy DMG forces original Game Boy hardware.

  • Palette [gearboy_palette] (Original|Sharp|B/W|Autumn|Soft|Slime)

    Select a color palette for Game Boy DMG games.

  • Allow Up+Down / Left+Right [gearboy_up_down_allowed] (Disabled|Enabled)

    Enabling this will allow pressing / quickly alternating / holding both left and right (or up and down in some games) directions at the same time.

    This may cause movement based glitches to occur in certain games.

    It's best to keep this core option disabled.

Joypad

User 1 input descriptors RetroPad Inputs
B
Select
Start
Up
Down
Left
Right
A

Compatibility

See also

Nintendo - Game Boy (+ Color)