crater

Crater is a free Sega Game Gear emulator written in C, with a Z80 assembler and disassembler included. It loads ROMs from its roms directory or from a command-line path, and offers fullscreen mode, integer scaling in a window, and a square-pixel option. Keyboard and joystick or controller input are supported; controller mappings can be defined in a gamecontrollerdb.txt file. For compatible games, it saves cartridge RAM to a .sav file, with options for a custom save location or disabling saves. The assembler converts Z80 assembly into a Game Gear ROM image and is described as complete. The disassembler attempts to turn ROM images into assembly but cannot distinguish code from data. Most games are described as playable with minor bugs, though Crater lacks audio, some uncommon CPU instructions, and advanced graphics features. Save states and custom keyboard mappings are not supported. Building requires a modern C11 compiler and SDL 2; only OS X and Linux are tested.