#ifdef _NES_MAPPER_CPP_ ///////////////////////////////////////////////////////////////////// // Mapper 255 void NES_mapper255::Reset() { // set CPU bank pointers set_CPU_banks(0,1,2,3); // set PPU bank pointers set_PPU_banks(0,1,2,3,4,5,6,7); set_mirroring(NES_PPU::MIRROR_VERT); //regs[0] = regs[2] = 0x0F; //regs[1] = regs[3] = 0x00; } uint8 NES_mapper255::MemoryReadLow(uint32 addr) { if(addr >= 0x5800) { return regs[addr & 0x0003] & 0x0F; } else { return (uint8)(addr >> 8); } } void NES_mapper255::MemoryWriteLow(uint32 addr, uint8 data) { if(addr >= 0x5800) { regs[addr & 0x0003] = data & 0x0F; } } void NES_mapper255::MemoryWrite(uint32 addr, uint8 data) { uint8 prg_bank = (uint8)((addr & 0x0F80) >> 7); uint8 chr_bank = (uint8)(addr & 0x003F); uint8 rom_bank = (uint8)((addr & 0x4000) >> 14); if(addr & 0x2000) { set_mirroring(NES_PPU::MIRROR_HORIZ); } else { set_mirroring(NES_PPU::MIRROR_VERT); } if(addr & 0x1000) {//16K PRG_ROM if(addr & 0x0040) {//upper half set_CPU_bank4(0x80*rom_bank+prg_bank*4+2); set_CPU_bank5(0x80*rom_bank+prg_bank*4+3); set_CPU_bank6(0x80*rom_bank+prg_bank*4+2); set_CPU_bank7(0x80*rom_bank+prg_bank*4+3); } else {//lower half set_CPU_bank4(0x80*rom_bank+prg_bank*4+0); set_CPU_bank5(0x80*rom_bank+prg_bank*4+1); set_CPU_bank6(0x80*rom_bank+prg_bank*4+0); set_CPU_bank7(0x80*rom_bank+prg_bank*4+1); } } else {//32K PRG_ROM set_CPU_bank4(0x80*rom_bank+prg_bank*4+0); set_CPU_bank5(0x80*rom_bank+prg_bank*4+1); set_CPU_bank6(0x80*rom_bank+prg_bank*4+2); set_CPU_bank7(0x80*rom_bank+prg_bank*4+3); } set_PPU_bank0(0x200*rom_bank+chr_bank*8+0); set_PPU_bank1(0x200*rom_bank+chr_bank*8+1); set_PPU_bank2(0x200*rom_bank+chr_bank*8+2); set_PPU_bank3(0x200*rom_bank+chr_bank*8+3); set_PPU_bank4(0x200*rom_bank+chr_bank*8+4); set_PPU_bank5(0x200*rom_bank+chr_bank*8+5); set_PPU_bank6(0x200*rom_bank+chr_bank*8+6); set_PPU_bank7(0x200*rom_bank+chr_bank*8+7); } ///////////////////////////////////////////////////////////////////// #endif