Chip-8

This is a Chip-8 emulator.

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.

Here's there is link to its wikipedia page, and here's a link to Cowgod's Chip-8 Technical Reference.

This implementation uses faiface pixel for graphics and beep for sound.

Additional Memory and Instructions

This emulator supports more memory than the original Chip 8 system, allowing you to run games and programs that require more memory. In addition, we have added two more instructions to the original set to enhance the compatibility with ROMs files generated with the "c8-compiler".

The two new instructions are:

• 9XY1: Save the value of register VX in the first 8 bits of the index register I, and the value of register VY in the last 8 bits of I.
• 9XY2: Save the first 8 bits of the value of index register I in register VX, and the last 8 bits of I in register VY. These instructions are not present in the original Chip 8 instruction set but are required to run ROMs files generated with the "c8-compiler".

To learn more about the "c8-compiler", please visit the c8-compiler Git repository.

Requirements

This Chip-8 emulator uses PixelGL and PixelGL uses OpenGL to render graphics. Because of that, OpenGL development libraries are needed for compilation. The dependencies are same as for GLFW.

The OpenGL version used is OpenGL 3.3.

• On macOS, you need Xcode or Command Line Tools for Xcode (xcode-select --install) for required headers and libraries.

• On Ubuntu/Debian-like Linux distributions, you need libgl1-mesa-dev and xorg-dev packages.

• On CentOS/Fedora-like Linux distributions, you need libX11-dev9el libXcursor-devel libXrandr-devel libXinerama-devel mesa-libGL-devel libXi-devel libXxf86vm-devel packages.

• See here for full details.

Installation

Chip8 executable for linux is provided in the release section.

Run

By default, it's going to run with the ROM file PONG.ch8. If you want to change it, you need to change the configuration.

Configuration

This Chip-8 emulator has a config.yml file that looks like this:

paths:
  beep: "../Chip-8/assets/beep.mp3"
  rom: "../Chip-8/assets/PONG.ch8"
  fonts: "../Chip-8/assets/chip8.font"

debug:
  on: "false"
  file: "DEBUG.json"

test:
  expectedStateROM1: "../fixtures/PONG.json"
  expectedStateROM2: "../fixtures/IBM_Logo.json"
  expectedStateROM3: "../fixtures/chip8_logo.json"
  ROM1: "../assets/PONG.ch8"
  ROM2: "../assets/IBM_Logo.ch8"
  ROM3: "../assets/chip8_logo.ch8"
  FONT: "../assets/chip8.font"

ROM Files

By default it's going to execute a Pong game. To change it to another you can modify the line

 rom: "../Chip-8/assets/PONG.ch8"

to a different relative root.

Debug mode

The debug mode runs the chip8 taking the state of the chip in every cycle and saving it into a json file with the name specified in the field "file". It can be activated modifying the config.yml file this way:

debug:
  on: "true"
  file: "DEBUG.json"
   

Test

The tests of this Chip-8 emulator compares the state of the chip with a desired state for certain ROM files specified in the "test" section.

It should not to be modified.

test:
  expectedStateROM1: "../fixtures/PONG.json"
  expectedStateROM2: "../fixtures/IBM_Logo.json"
  expectedStateROM3: "../fixtures/chip8_logo.json"
  ROM1: "../assets/PONG.ch8"
  ROM2: "../assets/IBM_Logo.ch8"
  ROM3: "../assets/chip8_logo.ch8"
  FONT: "../assets/chip8.font"

It also can be tested by running the chip8-test-suite.ch8 ROM in the assets folder, it was taken from Timendus github.

Keys

To quit the app you need to press the key Esc.

Here is the list of the keys mapping for the Chip 8:

KEYPAD	KEYBOARD
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