import sys
from typing import List, Optional
import pygame
ZOOM = 10
SCREEN_WIDTH = 64
SCREEN_HEIGHT = 32
BG_COLOR = (0xa0, 0xe6, 0xfa)
FG_COLOR = (0xff, 0xff, 0xff)
START_ADDR = 0x200
_MEM_SIZE = 4 * 1024
_FONTSET = [0xF0, 0x90, 0x90, 0x90, 0xF0, # 0
0x20, 0x60, 0x20, 0x20, 0x70, # 1
0xF0, 0x10, 0xF0, 0x80, 0xF0, # 2
0xF0, 0x10, 0xF0, 0x10, 0xF0, # 3
0x90, 0x90, 0xF0, 0x10, 0x10, # 4
0xF0, 0x80, 0xF0, 0x10, 0xF0, # 5
0xF0, 0x80, 0xF0, 0x90, 0xF0, # 6
0xF0, 0x10, 0x20, 0x40, 0x40, # 7
0xF0, 0x90, 0xF0, 0x90, 0xF0, # 8
0xF0, 0x90, 0xF0, 0x10, 0xF0, # 9
0xF0, 0x90, 0xF0, 0x90, 0x90, # A
0xE0, 0x90, 0xE0, 0x90, 0xE0, # B
0xF0, 0x80, 0x80, 0x80, 0xF0, # C
0xE0, 0x90, 0x90, 0x90, 0xE0, # D
0xF0, 0x80, 0xF0, 0x80, 0xF0, # E
0xF0, 0x80, 0xF0, 0x80, 0x80] # F
_KEYS = {
pygame.K_1: 0x1, pygame.K_2: 0x2, pygame.K_3: 0x3, pygame.K_4: 0xC,
pygame.K_q: 0x4, pygame.K_w: 0x5, pygame.K_e: 0x6, pygame.K_r: 0xD,
pygame.K_a: 0x7, pygame.K_s: 0x8, pygame.K_d: 0x9, pygame.K_f: 0xE,
pygame.K_z: 0xA, pygame.K_x: 0x0, pygame.K_c: 0xB, pygame.K_v: 0xF
}
[docs]def load_file(filepath: str) -> Optional[List[int]]:
try:
data = []
with open(filepath, "rb") as f:
file_bytes = f.read()
for i in range(len(file_bytes)):
data.append(int(file_bytes[i]))
except Exception as e:
print(f"Error: {e}")
sys.exit()
return data
class Memory:
def __init__(self):
# 4KB memory
self._ram = [0] * 4 * 1024
# stack
self._stack = []
for i in range(len(_FONTSET)):
self._ram[i] = _FONTSET[i]
@property
def ram(self):
return self._ram
def write(self, data: List[int]):
for i in range(len(data)):
self._ram[START_ADDR + i] = int(data[i])
def stack_pop(self):
return self._stack.pop()
def stack_push(self, x: int):
return self._stack.append(x)
class Display:
def __init__(self):
pygame.init()
pygame.display.set_caption("CHIP8")
self.canvas = pygame.display.set_mode((SCREEN_WIDTH * ZOOM, SCREEN_HEIGHT * ZOOM))
self.canvas.fill(BG_COLOR)
pygame.display.update()
def render(self, screen_buf: List[List[int]]):
self.draw_frame(screen_buf)
pygame.display.update()
def draw_frame(self, screen_buf: List[List[int]]):
self.canvas.fill(BG_COLOR)
for y in range(SCREEN_HEIGHT):
for x in range(SCREEN_WIDTH):
if screen_buf[y][x] == 1:
self.draw_pixel(x, y)
def draw_pixel(self, x: int, y: int):
pygame.draw.rect(
self.canvas,
FG_COLOR,
(x * ZOOM, y * ZOOM, ZOOM, ZOOM),
0
)
def quit(self):
pygame.quit()
class Keyboard:
def poll_event(self):
pass
class Instruction:
def __init__(self, val: int):
self.val = val
self.opcode = 0
self.x = 0
self.y = 0
self.n = 0
self.kk = 0
self.nnn = 0
self.flag = 0
def decode_opcode(self) -> int:
return self.val & 0xF000
def decode_x(self) -> int:
return (self.val & 0x0F00) >> 8
def decode_y(self) -> int:
return (self.val & 0x00F0) >> 4
def decode_n(self) -> int:
return self.val & 0x000F
def decode_kk(self) -> int:
return self.val & 0x00FF
def decode_nnn(self) -> int:
return self.val & 0x0FFF
def decode(self):
self.opcode = self.decode_opcode()
self.x = self.decode_x()
self.y = self.decode_y()
self.n = self.decode_n()
self.kk = self.decode_kk()
self.nnn = self.decode_nnn()
self.flag = self.decode_n()
class CPU:
def __init__(self):
self._memory = Memory()
# 8 bits register
self._reg_V = [0] * 16
# 16 bits register
self._reg_PC = START_ADDR
self._reg_I = 0
self.draw_flag = False
self._screen_buf = [[0 for _ in range(640)] for _ in range(320)]
self._keys_pressed_buf = [0] * 16
self._delay_timer = 0
self._sound_timer = 0
self._IR = None
@property
def memory(self):
return self._memory
def load_rom(self, data: List[int]):
self._memory.write(data)
def fetch(self):
high_byte = self._memory.ram[self._reg_PC]
low_byte = self._memory.ram[self._reg_PC + 1]
instruction = (high_byte << 8) | low_byte
self._reg_PC += 2
self._IR = Instruction(instruction)
def decode(self):
self._IR.decode()
def execute(self):
pass
def cycle(self):
self.fetch()
self.decode()
self.execute()
class Machine:
def __init__(self):
self.display = Display()
self.keyboard = Keyboard()
self.cpu = CPU()
[docs] def load_rom(self, rom_file: str):
data = load_file(rom_file)
self.cpu.load_rom(data)
def run(self):
while True:
self.cpu.cycle()
self.keyboard.poll_event()
self.display.render(self.cpu._screen_buf)
def main():
machine = Machine()
machine.run()
if __name__ == '__main__':
main()