Kutup's Super-Chip8 Emu

This project is an emulator for Chip 8 from 1970s. Quirks are matched to modern one. Special thanks to "Gulrak" and "Janitor Raus" -from r/EmuDev Discord Server- for helping me out in this project and pointing out the mistakes i did.

Sources used while doing this project: https://tobiasvl.github.io/blog/write-a-chip-8-emulator https://github.com/mattmikolay/chip-8/wiki/CHIP%E2%80%908-Technical-Reference https://github.com/mattmikolay/chip-8/wiki/CHIP%E2%80%908-Instruction-Set

For test roms check out: https://github.com/Timendus/chip8-test-suite

Integration

The Chip class contains everything needed for emulator to work. The chip doesn't directly use any pygame functions which makes it usable on any kind of project, not even a display is needed. To integrate this Chip to your projects, copy board folder which contains all the stuff needed for emulator.

Create Chip Instance

Create a new chip instance with

chip = Chip()

Chip class takes 4 (1 kwarg) args.

scale = 16 # This is just a variable stored in chip.screen for easier access later on

# Whatever if chip should pause itself after creation.
# Ticking while in paused state doesn't do anything
start_paused = False 

# Instruction count that will be executed per tick call. 60 fps = 10 * 60 = 600 Instructions per second
speed = 10

# To limit stack size for bad roms that might cause stackoverflow
stack_size = 32 

chip = Chip(scale, start_paused, speed, stack_size=stack_size)

Load Font Sprites and ROM

Before execution load font sprites to memory and load a rom file from a directory (default to ./rom/).

chip.load_sprites_to_mem()
chip.load_rom("slipperyslope.ch8")

Call Update Functions

We need to call some functions in order to chip to work properly. These are: Chip.tick, Chip.update_timers, Chip.keyboard.key_down, Chip.keyboard.key_up
Chip.update_timers must be called once every frame at 60 FPS (60Hz) before Chip.tick
Chip.tick can be called at a custom rate
Chip.keyboard.key_down and Chip.keyboard.key_up needs to be managed by developer as it might change depending on what framework/library you are using

Render Display

This will vary depending on your framework/library. I will give an example for pygame and official rendering function used in this project:

def render_display(chip, screen: pygame.Surface):
    for i in range(chip.screen.cols * chip.screen.rows):
        x = (i % chip.screen.cols) * chip.screen.scale
        y = math.floor(i / chip.screen.cols) * chip.screen.scale

        if chip.screen.display[i]:
            pygame.draw.rect(screen, (0, 255, 0), (x, y, chip.screen.scale, chip.screen.scale))

Keybindings

As this can also change depending on the framework/library you are using you might need to change your KEYBINDINGS in VirtualKeyboard class.

Keybindings are just a dict of Computer Key -> Chip-8 Key.