from .cart import Cart from .ppu import PPU from .controller import Controller RAM_MIRRORS_END = 0x1fff PPU_REGISTERS = 0x2000 PPU_REGISTERS_MIRRORS_END = 0x3fff class Bus: def __init__(self, ppu: PPU): # _______________ $10000 _______________ # | PRG-ROM | | | # | Upper Bank | | | # |_ _ _ _ _ _ _ _| $C000 | PRG-ROM | # | PRG-ROM | | | # | Lower Bank | | | # |_______________| $8000 |_______________| # | SRAM | | SRAM | # |_______________| $6000 |_______________| # | Expansion ROM | | Expansion ROM | # |_______________| $4020 |_______________| # | I/O Registers | | | # |_ _ _ _ _ _ _ _| $4000 | | # | Mirrors | | I/O Registers | # | $2000-$2007 | | | # |_ _ _ _ _ _ _ _| $2008 | | # | I/O Registers | | | # |_______________| $2000 |_______________| # | Mirrors | | | # | $0000-$07FF | | | # |_ _ _ _ _ _ _ _| $0800 | | # | RAM | | RAM | # |_ _ _ _ _ _ _ _| $0200 | | # | Stack | | | # |_ _ _ _ _ _ _ _| $0100 | | # | Zero Page | | | # |_______________| $0000 |_______________| self.memory = bytearray(0x10000) self.cart = None self.controllers = [None, None] self.ppu = ppu self.cycles = 0 self.frames = 0 self.def_read_func_idx() self.def_read_funcs() self.def_write_func_idx() self.def_write_funcs() def def_read_func_idx(self): self.read_func_idx = [ 0 if addr < 0x2000 else 1 if 0x8000 <= addr < 0x10000 else 2 if addr == 0x2002 else 3 if addr == 0x2004 else 4 if addr == 0x2007 else 5 if addr == 0x4016 else 6 if addr == 0x4017 else 7 if 0x2008 <= addr < 0x4000 else 8 if 0x4000 <= addr < 0x4016 else 8 for addr in range(0x10000)] self.read_func_idx = bytearray(self.read_func_idx) def def_read_funcs(self): self.read_funcs = [eval(f"self.read_fun_{i}") for i in range(9)] def read_fun_0(self, addr): return self.memory[addr & 0b00000111_11111111] def read_fun_1(self, addr): return self.cart.prg_rom[addr ^ 0x8000] def read_fun_2(self, addr): return self.ppu.read_status() def read_fun_3(self, addr): return self.ppu.oam_data[self.ppu.oam_addr] def read_fun_4(self, addr): return self.ppu.read_data() def read_fun_5(self, addr): return self.controllers[0].read() if self.controllers[0] else 0 def read_fun_6(self, addr): return self.controllers[1].read() if self.controllers[1] else 0 def read_fun_7(self, addr): return self.mem_read(addr & 0b00100000_00000111) def read_fun_8(self, addr): return 0 def def_write_func_idx(self): self.write_func_idx = [ 0 if addr < 0x2000 else 1 if addr == 0x2000 else 2 if addr == 0x2001 else 3 if addr == 0x2003 else 4 if addr == 0x2004 else 5 if addr == 0x2005 else 6 if addr == 0x2006 else 7 if addr == 0x2007 else 8 if addr == 0x4014 else 9 if addr == 0x4016 else 10 if addr == 0x4017 else 11 if 0x2008 <= addr < 0x4000 else 12 if 0x8000 <= addr < 0x10000 else 13 if 0x4000 <= addr < 0x4016 else 8 for addr in range(0x10000)] self.write_func_idx = bytearray(self.write_func_idx) def def_write_funcs(self): self.write_funcs = [eval(f"self.write_fun_{addr}") for addr in range(14)] def write_fun_0(self, addr, value): self.memory.__setitem__(addr & 0b00000111_11111111, value) def write_fun_1(self, addr, value): self.ppu.write_ctrl(value) def write_fun_2(self, addr, value): self.ppu.mask_set(value) def write_fun_3(self, addr, value): self.ppu.oam_addr = value def write_fun_4(self, addr, value): self.ppu.write_oam_data(value) def write_fun_5(self, addr, value): self.ppu.scrl_write(value) def write_fun_6(self, addr, value): self.ppu.addr_update(value) def write_fun_7(self, addr, value): self.ppu.write_data(value) def write_fun_8(self, addr, value): self.ppu.write_oam_dma(bytearray([self.mem_read(value << 8 | i) for i in range(256)])) def write_fun_9(self, addr, value): self.controllers[0].write(value) if self.controllers[0] else None def write_fun_10(self, addr, value): self.controllers[1].write(value) if self.controllers[1] else None def write_fun_11(self, addr, value): self.mem_write(addr & 0b00100000_00000111, value) def write_fun_12(self, addr, value): self.cart.write_prg_rom(addr ^ 0x8000, value) def write_fun_13(self, addr, value): pass def mem_read(self, addr): read = self.read_funcs[self.read_func_idx[addr]](addr) return read if read is not None else 0x00 if addr < 0x2000: return self.memory[addr & 0b00000111_11111111] if 0x8000 <= addr < 0x10000: return self.cart.prg_rom[addr ^ 0x8000] if addr == 0x2002: return self.ppu.read_status() if addr == 0x2004: return self.ppu.read_oam_data() if addr == 0x2007: return self.ppu.read_data() if addr == 0x4016: return self.controllers[0].read() if self.controllers[0] else 0 if addr == 0x4017: return self.controllers[1].read() if self.controllers[1] else 0 if 0x2008 <= addr < 0x4000: return self.mem_read(addr & 0b00100000_00000111) if 0x4000 <= addr < 0x4016: return 0 # if addr in [0x2000, 0x2001, 0x2003, 0x2005, 0x2006, 0x4014]: # print("Attempted to read from write-only PPU address: " + hex(addr)) # else: # print("Attempted to read from invalid memory location: " + hex(addr)) return 0x00 def mem_write(self, addr, value): self.write_funcs[self.write_func_idx[addr]](addr, value) return if addr < 0x2000: self.memory[addr & 0b00000111_11111111] = value elif addr == 0x2000: self.ppu.write_ctrl(value) elif addr == 0x2001: self.ppu.write_mask(value) elif addr == 0x2003: self.ppu.write_oam_addr(value) elif addr == 0x2004: self.ppu.write_oam_data(value) elif addr == 0x2005: self.ppu.write_scroll(value) elif addr == 0x2006: self.ppu.write_addr(value) elif addr == 0x2007: self.ppu.write_data(value) elif addr == 0x4014: self.ppu.write_oam_dma(bytearray([self.mem_read(value << 8 | i) for i in range(256)])) elif 0x4000 <= addr < 0x4016: pass elif addr == 0x4016: self.controllers[0].write(value) if self.controllers[0] else None elif addr == 0x4017: self.controllers[1].write(value) if self.controllers[1] else None elif 0x2008 <= addr < 0x4000: self.mem_write(addr & 0b00100000_00000111, value) elif 0x8000 <= addr < 0x10000: self.cart.write_prg_rom(addr ^ 0x8000, value) # elif addr == 0x2002: print("Attempted to write to read-only PPU address: " + hex(addr)) # else: print("Attempted to write to invalid memory location: " + hex(addr)) def reset(self): self.memory = bytearray(0x8000) self.cycles = 0 def tick(self, cpu_cycles): cycles = cpu_cycles * 3 self.cycles += cycles self.ppu.tick(cycles) def poll_nmi(self): return self.ppu.poll_nmi() def attach_cart(self, cart: Cart): self.cart = cart self.ppu.attach_cart(cart) def detach_cart(self): self.cart = None self.ppu.detach_cart() def attach_controller(self, controller: Controller, player=0): self.controllers[player] = controller def detach_controller(self, player=0): self.controllers[player] = None