/* * This file is part of the 65816 Emulator Library. * Copyright (c) 2018 Francesco Rigoni. * * https://github.com/FrancescoRigoni/Lib65816 * * 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, version 3. * * 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, see . */ #include "../Cpu65816.hpp" #define LOG_TAG "Cpu::executeSTZ" /** * This file contains the implementation for all STZ OpCodes. */ void Cpu65816::executeSTZ(OpCode &opCode) { Address dataAddress = getAddressOfOpCodeData(opCode); if (accumulatorIs8BitWide()) { mSystemBus.storeByte(dataAddress, 0x00); } else { mSystemBus.storeTwoBytes(dataAddress, 0x0000); addToCycles(1); } switch (opCode.getCode()) { case(0x9C): // STZ Absolute { addToProgramAddress(3); addToCycles(4); break; } case(0x64): // STZ Direct Page { if (Binary::lower8BitsOf(mD) != 0) { addToCycles(1); } addToProgramAddress(2); addToCycles(3); break; } case(0x9E): // STZ Absolute Indexed, X { addToProgramAddress(3); addToCycles(5); break; } case(0x74): // STZ Direct Page Indexed, X { if (Binary::lower8BitsOf(mD) != 0) { addToCycles(1); } addToProgramAddress(2); addToCycles(4); break; } default: { LOG_UNEXPECTED_OPCODE(opCode); } } }