Antons Multi-System-Emulator (AMSEL)

Cross-Plattform emulator product line in C++ (NES, DMG, CGB, GBA)

Web-Demo

Systems and Compatibility

Nintendo Entertainment System

• Behaviour was developed conforming to NTSC, added experimental PAL setting
• Most common Mappers implemented (MMC1, UxROM, CNROM, (MMC3), AxROM)
• MMC3 implementation is incomplete with simplified IRQ timing, some games have visual glitches

Nintendo Gameboy Color (amd dmg)

• DMG games are in black and white
• Most mappers implemented (MBC1, MBC2, MBC3, MBC5)
• RTC is missing
• Some games require very strict DMA timing and don't work correctly because of it
• Link Cable Implementation over TCP, Master Gameboy experiences audio glitches because of latency

Nintendo Gameboy Advance (incomplete)

• Working CPU and Bus
• Passes ARMWrestler, arm.gba and thumb.gba by jsmolka, most SingleStepTests
• PPU mode 3 and 4 working (bitmap modes), mode 0 backgrounds
• No audio yet
• Timings, Waitstates not implemented
• EEPROM, Flash not implemented
• Performance is weak
• TODO

Features

• Persistent settings (Volume, keybinds, language, etc.)
• Persistent savegames
• Debugger / Disassembler
• Local multiplayer (NES)
• EXPERIMENTAL Online Multiplayer (Gameboy, Only on Desktop)
• Gamepad support
• CRT-Shader
• Localization using JSON files (german, english included)
• React web interface, includes smartphone layout

Structure

The project is mostly written in C++. The individual consoles are decoupled from the interface, making the emulator easily extensible in theory, however some parts currently assume a NES / gameboy layout. The desktop frontend is implemented in Dear ImGui, running in an OpenGL 4.6 context.

I implemented the gameboy emulator in a separate project at first to learn Rust, which is why it's written in that language. To include it here, I defined a FFI in Rust CXX. Using Corrosion in Cmake it's trivial to then include it in an existing C++ project.

The web app frontend is written in React / Typescript. The emulator defines a javascript interface and is then compiled using emscripten to webassembly.

The entire project is developed as a Software Product Line (SPL). Individual features are able to be set at configure time as CMake options to create valid products according to the feature model (see here). The solution space is realized as a mix of preprocessor annotations and build system to create variability.

Build

requires CMake. requires Python 3 for building glad. requires Rust and Cargo for the Gameboy part.

Note: In MSVC, can only be built in release mode, because of an issue with rust debug level. Note: Static linking of libstdc++23 (as is default on mingw) requires a new version of g++ / clang.

building:

cd build
python -m venv .venv
.venv/Scripts/activate.<ps1/bat/sh...>
python -m pip install jinja2
cmake ..
make

building the web app

requires Emscripten and npm.

emcmake cmake .. -DFEATURE_WEB=ON -DFEATURE_DESKTOP=OFF
make

then in src/web:

npm install
npm run dev         (start dev server)
npm run build       (build website for delivery)

building as Libretro core

On windows, has to be built with MSVC in order to work with standard releases of retroarch.

cmake .. -DFEATURE_LIBRETRO_CORE=ON -DFEATURE_DESKTOP=OFF

Then use appropriate build tool.

running the tests

cmake .. -DFEATURE_TEST_SUITE=ON
make test

License

AMSEL is licensed under BSD-3. Parts of the nes ppu code were taken and edited from olcNES (see license).