nes-sim

A NES (Famicom) emulator core library written in Rust. Headless design decouples the emulation engine from the frontend, making it easy to integrate into different UI frameworks or testing environments.

Features

• Complete CPU emulation — 6502 processor with full addressing mode support and undocumented instructions
• PPU rendering — 256x240 resolution with sprite and background rendering
• APU audio — 5 standard channels (Pulse x2, Triangle, Noise, DMC)
• Expansion audio — VRC6, Namco 163, Sunsoft 5B, MMC5
• Mappers — Coverage of MMC1/MMC3/VRC series/Namco/Taito/Sunsoft and other common mappers
• Multi-system support — NTSC, PAL, DENDY
• Save states — Custom binary format with mapper validation
• Debug support — CPU/PPU state snapshots, per-channel mute
• Zero-dependency core — Core library has no external crate dependencies

Quick Start

Use as a library

[dependencies]
nes-sim = "0.1"

use nes_sim::NES;

let mut nes = NES::new("game.nes")?;
nes.reset();

// Run one frame (returns indexed color pixel data)
let frame = nes.clock();

// Output 44100Hz mono audio samples
let audio = nes.audio_samples();

Building

# Core library (no external dependencies)
cargo build

# Run tests
cargo test

Examples

cargo run --example export_frame -- "game.nes" "output.ppm" 180

cargo run --example desktop_frontend -- "game.nes""

Supported Mappers

• 0 (NROM)
• 1 (MMC1)
• 2 (UxROM)
• 3 (CNROM)
• 4 (MMC3)
• 5 (MMC5)
• 7 (AxROM)
• 11 (Color Dreams)
• 13 (CpROM)
• 19 (Namco 163)
• 21/23/25 (VRC4)
• 22 (VRC2)
• 24/26 (VRC6)
• 32 (Irem G-101)
• 33/48 (Taito TC0190)
• 34 (BNROM)
• 36
• 46
• 62
• 65 (Irem H-3001)
• 66 (GxROM)
• 67 (Sunsoft 3)
• 69 (FME-7)
• 70
• 71 (Camerica)
• 72
• 76
• 78
• 79/113 (NINA-003)
• 80 (Taito X1-005)
• 82 (Taito X1-017)
• 86 (JF-13)
• 87
• 88/154 (Namco 3433)
• 92 (JF-19)
• 94
• 97 (Irem Tam S1)
• 115
• 118 (TxSROM)
• 119 (TQROM)
• 152
• 162