Gearsystem is a cross-platform Sega Master System / Game Gear / SG-1000 emulator written in C++. ## Features - Accurate Z80 core, including undocumented opcodes and behaviour like R and MEMPTR registers. - Multi-Mapper support: SEGA, Codemasters, Korean, MSX, SG-1000, and ROM only cartridges. - External RAM support with save files. - Automatic region detection: NTSC-JAP, NTSC-USA, PAL-EUR. - Accurate VDP emulation including timing and SMS2 only 224 mode support. - Internal database for rom detection. - Audio emulation using SDL Audio and Sms_Snd_Emu library. - Saves battery powered RAM cartridges to file. - Save states. - Compressed rom support (ZIP deflate). - Game Genie and Pro Action Replay cheat support. - Full debugger with disassembler, breakpoints, debug symbols, memory editor, IO inspector and and VRAM viewer including tiles, sprites, backgrounds and palettes.