auto ICD2::read(uint24 addr, uint8 data) -> uint8 { addr &= 0x40ffff; //LY counter if(addr == 0x6000) { uint y = min((uint8)143, GameBoy::ppu.status.ly); return (y & ~7) | writeBank; } //command ready port if(addr == 0x6002) { data = packetSize > 0; if(data) { for(auto n : range(16)) r7000[n] = packet[0][n]; packetSize--; for(auto n : range(packetSize)) packet[n] = packet[n + 1]; } return data; } //ICD2 revision if(addr == 0x600f) { return 0x21; } //command port if((addr & 0x40fff0) == 0x7000) { return r7000[addr & 15]; } //VRAM port if(addr == 0x7800) { data = output[readBank * 512 + readAddress]; readAddress = (readAddress + 1) & 511; return data; } return 0x00; } auto ICD2::write(uint24 addr, uint8 data) -> void { addr &= 0xffff; //VRAM port if(addr == 0x6001) { readBank = data & 3; readAddress = 0; return; } //control port //d7: 0 = halt, 1 = reset //d5,d4: 0 = 1-player, 1 = 2-player, 2 = 4-player, 3 = ??? //d1,d0: 0 = frequency divider (clock rate adjust) if(addr == 0x6003) { if((r6003 & 0x80) == 0x00 && (data & 0x80) == 0x80) { reset(true); } switch(data & 3) { case 0: frequency = cpu.frequency / 4; break; //fast (glitchy, even on real hardware) case 1: frequency = cpu.frequency / 5; break; //normal case 2: frequency = cpu.frequency / 7; break; //slow case 3: frequency = cpu.frequency / 9; break; //very slow } r6003 = data; return; } if(addr == 0x6004) { r6004 = data; return; } //joypad 1 if(addr == 0x6005) { r6005 = data; return; } //joypad 2 if(addr == 0x6006) { r6006 = data; return; } //joypad 3 if(addr == 0x6007) { r6007 = data; return; } //joypad 4 }