GearSystem is a Sega Master System / Game Gear emulator written in C++ that runs on iOS, Raspberry Pi, Mac, Windows and Linux. The main focus of this emulator is readability of source code with very high compatibility.

- Highly accurate Z80 core.
- Multi-Mapper support: SEGA, Codemasters, and ROM only cartridges.
- External RAM support with save files.
- Automatic region detection: NTSC-JAP, NTSC-USA, PAL-EUR.
- SMS2 only 224 mode support.
- Internal database for rom detection.
- Sound emulation using SDL Audio and Sms_Snd_Emu library.
- Integrated disassembler. It can dump the full disassembled memory to a text file or access it in real time.
- Compressed rom support (ZIP deflate).
- Multi platform. Runs on Windows, Linux, Mac OS X, Raspberry Pi and iOS.

GearSystem changelog:

Windows, Linux, macOS and Raspberry Pi 4:
Full Debugger for Master System, Game Gear and SG-1000.
Z80 disassembler with breakpoints and debug symbols.
TMS9918 inspector, including pattern tables, name tables, sprites and palettes.
Memory Editor.
Open rom using cli argument.
Emulation parameters like region, system, mapper, etc.
All platforms:
Load gamepad mappings from file.
Several bug fixes.