Chip-8 Emulator

A simple chip-8 emulator written using C++ and SDL2 library.

What is an emulator?

An emulator is a computer program that mimics the internal design and functionality of a computer system (System A). It allows users to run software designed for this specific system (Sytem A) on a totally different computer system or architecture (System B).

What is chip-8?

CHIP-8 is an interpreted programming language, developed by Joseph Weisbecker. It was initially used on the COSMAC VIP and Telmac 1800 8-bit microcomputers in the mid-1970s. CHIP-8 programs are run on a CHIP-8 virtual machine. It was made to allow video games to be more easily programmed for these computers, but CHIP 8 is still used today, due to its simplicity, and consequently on any platform and its teaching of programming Binary numbers.

Chip-8 Architecture

Variable	Description
unsigned short opcode	Stores the current opcode, out of a total of 25 opcodes
unsigned char memory[4096]	Emulated memory of 4KB
unsigned char V[16]	15 8-bit general purpose registers
unsigned short I	Index register
unsigned short pc	Program counter
unsigned char gfx[64 * 32]	Graphics for 64x32 pixels (black and white)
unsigned char delay_timer	Register that counts at 60 Hz
unsigned short stack[16]	Stack used to remember the current location before a jump is performed
unsigned short sp	Stack pointer to remember current level of stack
unsigned char key[16]	Stores the current state of the key for HEX based keypad

Compiling and Running

Requires cmake and SDL2:

$ sudo apt-get install cmake libsdl2-dev

Compile:

$ mkdir build
$ cd build
$ cmake ..
$ make

Run:

./chip8 <ROM file>

License

Distributed under the MIT License. See LICENSE.md for more information.

References

• https://multigesture.net/articles/how-to-write-an-emulator-chip-8-interpreter/
• https://en.wikipedia.org/wiki/CHIP-8
• https://austinmorlan.com/posts/chip8_emulator/