A CHIP-8 emulator written in C, built as a portfolio project for [boot.dev](https://boot.dev).
CHIP-8 is an interpreted programming language from the late 1970s, originally used on the COSMAC VIP and other early microcomputers. This emulator reproduces the original hardware behavior - loading ROM files into a simulated 4KB memory space, decoding and executing 2-byte opcodes, rendering monochrome graphics, handling keyboard input, and producing sound.
## Features
- **Complete instruction set** - All 35 standard CHIP-8 opcodes implemented
- **64x32 monochrome display** - Rendered at 10x scale via Raylib
- **Keyboard input** - Full hex keypad mapped to QWERTY
- **Sound emulation** - 440Hz sine wave beep when the sound timer is active
- **Delay & sound timers** - Decrement at 60Hz, matching original hardware timing
- **CPU clock** - 600Hz (10 cycles per frame at 60 FPS)
- **Bounds checking** - Validates ROM size, key registers, and memory addresses
| `test_files/ibm_logo.ch8` | Classic IBM logo - the standard CHIP-8 test program |
| `test_files/space_invaders.ch8` | Space Invaders - a fully playable game |
| `test_files/test_opcode.ch8` | Opcode validation ROM |
## Testing
```bash
# Run the unit test suite
make test
# Generate a test coverage report (HTML)
make coverage
```
The coverage report is generated at `.bin/coverage/index.html`.
## Architecture
The project is split into two layers:
- **`chip8.c` / `chip8.h`** - Platform-independent CPU emulator. Handles memory, opcode decoding/execution, registers, timers, and display state. No Raylib dependency - portable to other platforms by swapping only the frontend.
- **`main.c`** - Platform-specific frontend built with Raylib. Manages the window, rendering, keyboard input, audio, and the main loop driving the CPU at the correct clock speed.
