///////////////////////////////////////////////////////////////////// // Mapper 68 void NES_mapper68::Reset() { // set CPU bank pointers set_CPU_banks(0,1,num_8k_ROM_banks-2,num_8k_ROM_banks-1); regs[0] = 0; regs[1] = 0; regs[2] = 0; regs[3] = 0; } void NES_mapper68::MemoryWrite(uint32 addr, uint8 data) { switch(addr & 0xF000) { case 0x8000: { set_PPU_bank0(data*2+0); set_PPU_bank1(data*2+1); } break; case 0x9000: { set_PPU_bank2(data*2+0); set_PPU_bank3(data*2+1); } break; case 0xA000: { set_PPU_bank4(data*2+0); set_PPU_bank5(data*2+1); } break; case 0xB000: { set_PPU_bank6(data*2+0); set_PPU_bank7(data*2+1); } break; case 0xC000: { regs[2] = data; SyncMirror(); } break; case 0xD000: { regs[3] = data; SyncMirror(); } break; case 0xE000: { regs[0] = (data & 0x10) >> 4; regs[1] = data & 0x03; SyncMirror(); } break; case 0xF000: { set_CPU_bank4(data*2); set_CPU_bank5(data*2+1); } break; } } void NES_mapper68::SyncMirror() { if(regs[0]) { if (regs[1] == 0) { set_PPU_bank8(regs[2] + 0x80); // + 0x20000 set_PPU_bank9(regs[3] + 0x80); set_PPU_bank10(regs[2] + 0x80); set_PPU_bank11(regs[3] + 0x80); } else if (regs[1] == 1) { set_PPU_bank8(regs[2] + 0x80); set_PPU_bank9(regs[2] + 0x80); set_PPU_bank10(regs[3] + 0x80); set_PPU_bank11(regs[3] + 0x80); } else if (regs[1] == 2) { set_PPU_bank8(regs[2] + 0x80); set_PPU_bank9(regs[2] + 0x80); set_PPU_bank10(regs[2] + 0x80); set_PPU_bank11(regs[2] + 0x80); } else if (regs[1] == 3) { set_PPU_bank8(regs[3] + 0x80); set_PPU_bank9(regs[3] + 0x80); set_PPU_bank10(regs[3] + 0x80); set_PPU_bank11(regs[3] + 0x80); } } else { if (regs[1] == 0) { set_mirroring(NES_PPU::MIRROR_VERT); } else if (regs[1] == 1) { set_mirroring(NES_PPU::MIRROR_HORIZ); } else if (regs[1] == 2) { set_mirroring(0,0,0,0); } else if (regs[1] == 3) { set_mirroring(1,1,1,1); } } } /////////////////////////////////////////////////////////////////////