NES Emulator written from scratch in C.
Can be built for Linux, Windows and webassembly!
https://junnys6018.github.io/nes/
This emulator has a real time waveform visualisation of each channel, (square 1 and 2, triangle and noise channel). Video demo can be found here
- Clone repo with
git clone --recursive https://github.com/junnys6018/NES-Emulator.git. - If the repository was cloned non-recursively run
git submodule update --initto clone required submodules. - Run
./scripts/GenerateLinuxProjects.shor./scripts/GenerateWindowsProjects.bat. - Build files are in the
builddirectory. - Build with make on linux or msvc on windows.
- Make sure you build in release, otherwise the emulation will not run in real time.
Here is a rough guide for targeting webassembly. If you just want to get hold of the webassembly module and javascript glue code, it is provided in the web directory as emu.js and emu.wasm. Included is an example consuming the webassembly module.
- Install emscripten
- Download the emscripten toolchain file here
- Activate emscripten
source <path/to/emsdk/emsdk_env.sh>
cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=<path/to/Emscripten.cmake> -DCMAKE_BUILD_TYPE=Release
cd build
make
The only dependency this project has is SDL. On windows the library is prebuilt in the repo, so you dont have to download and install SDL yourself.
On linux run sudo apt-get install libsdl2-dev
The emulator can be run from the command line with NES-Emulator.exe [rom.nes]
Alternatively you can just run the program without arguments and goto Settings -> Load Rom...
On Windows make sure the executable can find sdl.dll, this is provided in application, if you try to run the executable from the build directory the program will crash. Building in release will automatically copy the executable from the build folder into application. Make sure you run the executable in the same directory as sdl.dll
NES cartidges have thier own circuitry that can modify the behaviour of the console, many cartridges provide bank switching, and have the ability to generate hardware interrupts. Some cartridges even have thier own sound systems to expand the audio capabilities of the NES. The nes emulation community have assigned numbers to each variant of cartridge, called a "mapper number".
Currently the following mappers have been implemented
| # | Name | Some Games |
|---|---|---|
| 000 | NROM | Super Mario Bros. 1, Donkey Kong, Balloon Fight |
| 001 | MMC1 | Legend of Zelda, Dr. Mario, Metroid |
| 002 | UxROM | Mega Man, Duck Tales, Castlevania |
| 003 | CNROM | Arkanoid, Cybernoid, Solomon's Key |
| 004 | MMC3 | Super Mario Bros 2 and 3, Silver surfer |
There are plans to implement mappers 7 and 9 in the future, which covers most of the games on the NES
| Button | Key |
|---|---|
| A | X |
| B | Z |
| Start | Enter |
| Select | Tab |
| Up | Up arrow |
| Down | Down arrow |
| Left | Left arrow |
| Right | Right arrow |
Other controllers may work but are untested
| Button | Key (PS4) | Key (Xbox) |
|---|---|---|
| A | X | A |
| B | O | B |
| Start | Options | Start |
| Select | Share | Back |
| Up | D-pad Up | D-pad Up |
| Down | D-pad Down | D-pad Down |
| Left | D-pad Left | D-pad Left |
| Right | D-pad Right | D-pad Right |
This emulator has the abilty to pause the emulation and step through it, here are the controls
| Key | Action |
|---|---|
| Space | Emulate one CPU instruction |
| F | Emulate one frame |
| P | Emulate one PPU cycle |