GearBoy

Gearboy is an open source emulator for the Game Boy and Game Boy Color written in C++. Its CPU emulation is highly accurate, including instruction timing.

Gearboy passes Blargg’s “cpu_instrs.gb” and “instr_timing.gb” test ROMs. It also emulates the LCD controller, so everything is drawn to the screen as it would be on the real hardware.

Gearboy supports all common memory bank controllers and their battery-backed RAM.

Its Game Boy compatibility is very good, while its Game Boy Color emulation has historically been somewhat less accurate.