95 lines
3.3 KiB
C++
95 lines
3.3 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 <cmath>
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#include "SystemBus.hpp"
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#include "Log.hpp"
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#define LOG_TAG "SystemBus"
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void SystemBus::registerDevice(SystemBusDevice *device) {
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mDevices.push_back(device);
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}
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void SystemBus::storeByte(const Address &address, uint8_t value) {
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for (SystemBusDevice *device : mDevices) {
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Address decodedAddress;
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if (device->decodeAddress(address, decodedAddress)) {
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device->storeByte(decodedAddress, value);
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return;
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}
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}
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}
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void SystemBus::storeTwoBytes(const Address &address, uint16_t value) {
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for (SystemBusDevice *device : mDevices) {
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Address decodedAddress;
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if (device->decodeAddress(address, decodedAddress)) {
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uint8_t leastSignificantByte = (uint8_t)(value & 0xFF);
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uint8_t mostSignificantByte = (uint8_t)((value & 0xFF00) >> 8);
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device->storeByte(decodedAddress, leastSignificantByte);
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decodedAddress.incrementOffsetBy(1);
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device->storeByte(decodedAddress, mostSignificantByte);
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return;
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}
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}
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}
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uint8_t SystemBus::readByte(const Address &address) {
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for (SystemBusDevice *device : mDevices) {
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Address decodedAddress;
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if (device->decodeAddress(address, decodedAddress)) {
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return device->readByte(decodedAddress);
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}
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}
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return 0;
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}
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uint16_t SystemBus::readTwoBytes(const Address &address) {
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for (SystemBusDevice *device : mDevices) {
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Address decodedAddress;
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if (device->decodeAddress(address, decodedAddress)) {
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uint8_t leastSignificantByte = device->readByte(decodedAddress);
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decodedAddress.incrementOffsetBy(sizeof(uint8_t));
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uint8_t mostSignificantByte = device->readByte(decodedAddress);
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uint16_t value = ((uint16_t)mostSignificantByte << 8) | leastSignificantByte;
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return value;
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}
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}
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return 0;
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}
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Address SystemBus::readAddressAt(const Address &address) {
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Address decodedAddress { 0x00, 0x0000 };
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for (SystemBusDevice *device : mDevices) {
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if (device->decodeAddress(address, decodedAddress)) {
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// Read offset
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uint8_t leastSignificantByte = device->readByte(decodedAddress);
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decodedAddress.incrementOffsetBy(sizeof(uint8_t));
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uint8_t mostSignificantByte = device->readByte(decodedAddress);
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uint16_t offset = ((uint16_t)mostSignificantByte << 8) | leastSignificantByte;
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// Read bank
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decodedAddress.incrementOffsetBy(sizeof(uint8_t));
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uint8_t bank = device->readByte(decodedAddress);
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return Address(bank, offset);
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}
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}
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return decodedAddress;
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}
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