chip8

Chip8 is a small emulator for the CHIP-8 interpreter language used in the COSMAC VIP and Telmac 1800 system.

This implementation uses C++ for the core functionality and a SDL2 backend completes the emulator with sound, keyboard input and GL display.

To install the SDL2 library, use sudo apt-get install libsdl2-dev (for Ubuntu).

To use the emulator:

Introduction

Chip-8 is more of a virtual machine than a physical one.
It interprets the instructions and replicates the functionality of the original machine.
Commonly interpreted on 4K systems such as Cosmac VIP in mid 1970s
It was made to allow video games more easily programable for these machines as games written in chip8 language could easily run using the chip8 emulator.

16 8bit registers labeled from V0 to VF, VF is special as it is used as flag.
4K bytes memory i.e 0.000 to 0xFFF
Address space is divided into 3 sections:
- 0x000 to 0x1FF - (first 512 bytes)reserved for the interpreter
- 0x050 to 0x0A0 - for characters 0 through F
- 0x200 to 0xFFF - for ROMS
16 bit index register for storing the memory address used in operations
16 bit Program Counter which holds the address of next instruction to be excecuted.
16 level stack to keep track of the order of excecution.
8 bit stack pointer (top) for using the stack.
8 bit delay timer for timing, decrements at rate of 60Hz.
8 bit sound timer for sound, similar behaviour as the delay timer.
16 input keys which match the first 16 hex values (0 through F).

INVADERS:
- start the game using W
- left: Q
- right: E
- W: shoot
BRIX:
- Q to move left
- E to move right
PONG: 2 player game
- Player1: 1 and Q to move up and down
- Player2: 4 and R to move up and down
TANK:
- 2 to move down
- Q to turn left
- E to turn right
- S to move up
- W to fire
TETRIS:
- W to move left
- E to move right
- Q to rotate piece