There’s something special about emulation. You’re not just writing code—you’re recreating a piece of computing history. The CHIP-8 is the perfect introduction: simple enough to implement in a weekend, complex enough to teach you the fundamentals.

What is CHIP-8?

CHIP-8 is an interpreted programming language from the 1970s, designed to run on 8-bit microcomputers. It has:

  • 4KB of memory
  • 16 8-bit registers
  • A 64x32 monochrome display
  • 16-key hex keypad
  • 35 opcodes

The Architecture

My emulator has three main components:

1. CPU

  • Fetches, decodes, and executes instructions
  • Manages the program counter and registers
  • Handles the 60Hz timer updates

2. Display

  • 64x32 pixel framebuffer
  • XOR-based drawing (sprites toggle pixels)
  • Collision detection for games

3. Input

  • Maps keyboard to the 16-key hex pad
  • Blocking and non-blocking input modes

WebAssembly Integration

The fun part was making it run in the browser. With Rust’s wasm-bindgen:

  • The core emulator is platform-agnostic Rust
  • A thin JavaScript wrapper handles the canvas
  • Audio beeps through the Web Audio API

Challenges

Timing: CHIP-8 games expect 60Hz. Too fast and they’re unplayable, too slow and they’re sluggish. I ended up using requestAnimationFrame with cycle counting.

Display quirks: Some games rely on specific sprite drawing behavior. Getting Space Invaders to work required careful reading of the original CHIP-8 specification.

Playing Games

Once it worked, I could play:

  • Pong (the classic)
  • Space Invaders
  • Tetris
  • Pac-Man

There’s something deeply satisfying about seeing these classics run on code you wrote.

Resources

If you want to build your own:

Emulation is a fantastic way to learn low-level programming. You deal with memory, bitwise operations, and hardware interfaces—all skills that translate to modern systems programming.