CHIP-8 Emulator

A complete CHIP-8 emulator implementation written in C++ with SDL2 and OpenGL rendering.

About CHIP-8

CHIP-8 is an interpreted programming language developed in the 1970s for early microcomputers. It was designed to make game programming easier by providing a simple virtual machine with 35 opcodes. This emulator accurately replicates the CHIP-8 system, allowing you to run classic CHIP-8 programs and games.

Features

• Full implementation of all 35 CHIP-8 opcodes
• 64x32 monochrome display with configurable scaling
• 16-key hexadecimal keypad input
• Configurable CPU cycle delay for game speed control
• SDL2-based graphics rendering
• Cross-platform support

Dependencies

• CMake 3.14 or higher
• C++17 compatible compiler
• SDL2
• GLUT (OpenGL Utility Toolkit)
• ImGui (included in external/)

Installing Dependencies

macOS:

brew install sdl2 cmake

Ubuntu/Debian:

sudo apt-get install libsdl2-dev cmake freeglut3-dev

Fedora:

sudo dnf install SDL2-devel cmake freeglut-devel

Building

mkdir build
cd build
cmake ..
make

This will create an executable named main in the build directory.

Usage

./main <scale> <delay> <rom>

Arguments:

• scale: Video scale factor (e.g., 10 for 640x320 window)
• delay: CPU cycle delay in milliseconds (lower = faster, typical: 1-5)
• rom: Path to CHIP-8 ROM file

Example:

./main 10 2 ../chip8-test-rom.ch8

Keyboard Controls

The CHIP-8 keypad is mapped to your keyboard as follows:

CHIP-8 Keypad       Keyboard Layout
┌───┬───┬───┬───┐   ┌───┬───┬───┬───┐
│ 1 │ 2 │ 3 │ C │   │ 1 │ 2 │ 3 │ 4 │
├───┼───┼───┼───┤   ├───┼───┼───┼───┤
│ 4 │ 5 │ 6 │ D │   │ Q │ W │ E │ R │
├───┼───┼───┼───┤   ├───┼───┼───┼───┤
│ 7 │ 8 │ 9 │ E │   │ A │ S │ D │ F │
├───┼───┼───┼───┤   ├───┼───┼───┼───┤
│ A │ 0 │ B │ F │   │ Z │ X │ C │ V │
└───┴───┴───┴───┘   └───┴───┴───┴───┘

Press ESC to quit the emulator.

Project Structure

chip-8/
├── includes/
│   ├── chip8.h          # CHIP-8 CPU and memory definitions
│   └── platform.h       # SDL2 platform layer
├── src/
│   ├── chip8.cpp        # CHIP-8 emulator core implementation
│   └── platform.cpp     # Platform-specific rendering and input
├── external/
│   └── imgui/           # ImGui library files
├── main.cpp             # Entry point and main loop
├── CMakeLists.txt       # Build configuration
├── chip8-test-rom.ch8   # Test ROM
└── README.md

Technical Details

• Memory: 4KB RAM (4096 bytes)
• Display: 64x32 pixels, monochrome
• Registers: 16 8-bit general-purpose registers (V0-VF)
• Stack: 16 levels for subroutine calls
• Timers: 60Hz delay and sound timers
• Instruction Set: 35 opcodes with table-based dispatch

Resources

• CHIP-8 Test ROM - Included test ROM for verification
• More CHIP-8 Games
• CHIP-8 Technical Reference

License

This project is open source and available for educational purposes.