nes-emu

A NES emu in Rust

Features

• Implements full CPU instruction emulation.
• Passing 110 tests out of 136 tests from 100thCoin/AccuracyCoin
• Support iNES mapper 0-4, 7
• Accurate PPU VBLANK timing & NMI control
• Plays Battletoads
• Battery save support through whole RAM snapshot

Building

Make sure you have SDL2 installed for the main branch (egui is used in separated branch) for static linking, other than that just run:

cargo build --release

To build the emulator then use

./target/release/emulator <rom path>

To start the emulator and load the ROM.

Bindings

Currently only supports single controller with static binding:

Key	Controller
Z	A
X	B
Return	Start
Space	Select
Arrow keys	D-Pad

Test Results

AccuracyCoin run all result screen:

Gameplay Screenshots

Roadmap

• Improve DMA accuracy by implementing RDY line control, get/put cycles, and cycle alignment rather than current hard-coded stuff Implementation done, but not passing tests.
• Implement correct instruction behavior for SHA, SHS, SHX, SHY to account for RDY line assertion when DMA occurrence
  • Unknown requirements for this.
• Improve NMI overlapping behavior
• Improve PPU accuracy
• Improve APU accuracy
• Add randomized RAM initialization for components
• Add widgets for emulator UI
• Add save state support