nes.rs

An emulator for the Nintendo Entertainment System written in Rust, with SDL2 and web frontends.

🎮 Try it out in your browser!

emu.mp4

This isn't meant to be a full-featured or 100% accurate emulator, but rather a fun educational project. It still aims to be fairly accurate, emulating some hardware quirks such as unofficial CPU opcodes.

Running (SDL2)

Ensure that you have cargo installed.

cargo build --release
cd target/release
./nesrs <path-to-rom>

Controls are bound to:

• Z: B
• X: A
• A: Select
• S: Start
• Arrow keys: Up/Down/Left/Right

Meta controls (Not controller inputs):

• Space: Pause/unpause emulation
• [: Decrease volume
• ]: Increase volume
• 1-5: Load save state [1-5]
• Shift+[1-5]: Write save state to slot [1-5]

Running the WASM frontend locally

Ensure that you have wasm-pack, Node and pnpm installed. First, build the wasm crate:

cd emu-wasm
wasm-pack build

Then just spin up the frontend:

cd web
pnpm i
pnpm dev

Testing

cargo test

This will run test ROMs for the CPU emulation.

Passing tests

• nestest (kevtris)
• instr_test-v5 (blargg)

Compatability

iNES Mappers 0, 1, 2, 3, 4 and 9 are supported. Any game that uses a different mapper will not work for now. To find out which mapper a game uses, search it on NesCartDB.

TODO

Emulation

• Accurate audio emulation
  • Implement DMC channel for APU
  • Investigate issues with envelope/sweep unit
  • Fix issues with buffer underrun/overrun and reduce audio latency
• Investigate performance issues
• Implement more mappers
  • Mapper 4 (MMC3)
  • Mapper 5 (MMC5)
  • Mapper 7 (AxROM)
  • Mapper 9 (MMC2)
  • Mapper 10 (MMC4)
  • Mapper 66 (GxROM)
• Run test ROMs for PPU emulation

QOL

• Save states
• Remappable controls

Resources

• Nesdev Wiki
• 6502 CPU opcode reference
• Unofficial opcodes
• NES test roms
• NesCartDB