Yet another Chip-8 emulator interpreter.

History

Chip-8 was a virtual machine/programming language developed by RCA engineer Joseph Weisbecker in 1977 for the COSMAC VIP microcomputer. It was intended as a simple way to make small programs and games for the computer. Chip-8 soon spread to the other computers, like Finnish Telmac 1800, the Australian DREAM 6800, ETI-660 and MicroBee, and the Canadian ACE VDU.

Technical information

The original Chip-8 was designed with the following specifications:

• Memory: Chip-8 has direct access to up 4KB RAM
• Display: 64x32 pixels monochrome, ie. Black or White
• Keypad: 16 keys, labelled 0 through F, and were arranged in a 4x4 grid.
• A program counter, often called "PC", which point at the current instruction in memory
• One 16-bit index register called "I" which is used to point at locations in memory
• A stack for 16-bit addresses, which is used to call subroutines/functions and return from them
• An 8-bit delay timer which is decremented at a rate of 60Hz (60 times per second) until reaches 0
• An 8-bit sound timer which functions like the delay timer, but which also gives off a beeping sound as long as it's not 0
• 16 8-bit(one byte) general-purpose variable registers numbered 0 through F hexadecimal, ie. 0 through 15 in decimal, called V0 through VF
  • VF is also used as a flag register; many instructions will set it to either 1 or 0 based on some rule, for example using it as a carry flag

Building

Requirements

• SDL2:
  • Minimum version required: 2.24.2
  • Required for rendering and input management.
• CMake:
  • Minimum version requiered: 3.21
  • Required for automatic build.

Procedures

Linux

For building, you can use this procedure:

$ mkdir build
$ cmake -B build -DCMAKE_BUILD_TYPE=Release
$ cmake --build build

Windows

_{Note: Not tested, for while, there is no build procedure.}

Running

Linux

After building with above procedure, the binary will be located in build/bin/ directory. Run the program using: $ ./build/bin/Chip8 <path-to-rom>

Windows

I don't know.

_{There are some test roms located in roms directory, you can use them. :)}

Command-line arguments

long	short	value	description
clock	c	int	Set cpu clock speed(0-1000).
width		int	Set window width to desired resolution
height		int	Set window height to desired resolution
help	h		Show help message and then exits.
verbose	v		Enable log output on terminal.
quiet	q		Disbale log ouput on terminal.

_{Note: For while, the cpu screen will be stretched to the current resolution.}

Controls:

Keyboard (This is the default keymap)

1 2 3 4
Q W E R
A S D F
Z X C V

COSMAC VIP Keypad

1 2 3 C
4 5 6 D
7 8 9 E
A 0 B F

TODOs

• Graphical user interface.
• Keyboard shortcuts for opening, reseting and exiting the emulator.

Roms

• Revival Studio's Chip-8 Program Pack

References

• Cowgod's Chip-8 Technical Reference v1.0
• Tobias V.Langhoff
• Chip-8 Extensions and compatibility
• Chip-8 Test Suite

License

This project is licensed under the MIT license, so you are free to do almost everything you want.

Contributing

Anyone is welcome to contribute! Here is our contributors: