69 lines
1.9 KiB
C++
69 lines
1.9 KiB
C++
/*
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* This file is part of the 65816 Emulator Library.
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* Copyright (c) 2018 Francesco Rigoni.
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*
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* https://github.com/FrancescoRigoni/Lib65816
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 3.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "../Cpu65816.hpp"
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#define LOG_TAG "Cpu::executeSTX"
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/**
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* This file contains the implementation for all STX OpCodes.
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*/
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void Cpu65816::executeSTX(OpCode &opCode) {
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Address dataAddress = getAddressOfOpCodeData(opCode);
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if (accumulatorIs8BitWide()) {
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mSystemBus.storeByte(dataAddress, Binary::lower8BitsOf(mX));
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} else {
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mSystemBus.storeTwoBytes(dataAddress, mX);
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addToCycles(1);
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}
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switch (opCode.getCode()) {
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case(0x8E): // STX Absolute
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{
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addToProgramAddress(3);
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addToCycles(4);
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break;
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}
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case(0x86): // STX Direct Page
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{
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if (Binary::lower8BitsOf(mD) != 0) {
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addToCycles(1);
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}
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addToProgramAddress(2);
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addToCycles(3);
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break;
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}
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case(0x96): // STX Direct Page Indexed, Y
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{
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if (Binary::lower8BitsOf(mD) != 0) {
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addToCycles(1);
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}
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addToProgramAddress(2);
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addToCycles(4);
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break;
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}
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default: {
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LOG_UNEXPECTED_OPCODE(opCode);
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}
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}
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}
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