/* * This file is part of libsidplayfp, a SID player engine. * * Copyright 2011-2015 Leandro Nini * Copyright 2007-2010 Antti Lankila * Copyright 2000 Simon White * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #include "mmu.h" #include "Banks/Bank.h" #include "Banks/IOBank.h" namespace libsidplayfp { class Bank; MMU::MMU(EventScheduler &scheduler, IOBank* ioBank) : eventScheduler(scheduler), loram(false), hiram(false), charen(false), ioBank(ioBank), zeroRAMBank(*this, ramBank) { cpuReadMap[0] = &zeroRAMBank; cpuWriteMap[0] = &zeroRAMBank; for (int i = 1; i < 16; i++) { cpuReadMap[i] = &ramBank; cpuWriteMap[i] = &ramBank; } } void MMU::setCpuPort(uint8_t state) { loram = (state & 1) != 0; hiram = (state & 2) != 0; charen = (state & 4) != 0; updateMappingPHI2(); } void MMU::updateMappingPHI2() { cpuReadMap[0xe] = cpuReadMap[0xf] = hiram ? (Bank*)&kernalRomBank : &ramBank; cpuReadMap[0xa] = cpuReadMap[0xb] = (loram && hiram) ? (Bank*)&basicRomBank : &ramBank; if (charen && (loram || hiram)) { cpuReadMap[0xd] = cpuWriteMap[0xd] = ioBank; } else { cpuReadMap[0xd] = (!charen && (loram || hiram)) ? (Bank*)&characterRomBank : &ramBank; cpuWriteMap[0xd] = &ramBank; } } void MMU::reset() { ramBank.reset(); zeroRAMBank.reset(); // Reset the ROMs to undo the hacks applied kernalRomBank.reset(); basicRomBank.reset(); loram = false; hiram = false; charen = false; updateMappingPHI2(); } }