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70 lines
1.7 KiB
C++
70 lines
1.7 KiB
C++
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//
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// DiskROM.cpp
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// Clock Signal
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//
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// Created by Thomas Harte on 07/01/2018.
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// Copyright © 2018 Thomas Harte. All rights reserved.
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//
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#include "DiskROM.hpp"
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using namespace MSX;
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DiskROM::DiskROM(const std::vector<uint8_t> &rom) :
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WD1770(P1793),
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rom_(rom) {
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set_is_double_density(true);
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}
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void DiskROM::write(uint16_t address, uint8_t value) {
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switch(address) {
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case 0x7ff8: case 0x7ff9: case 0x7ffa: case 0x7ffb:
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set_register(address, value);
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break;
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case 0x7ffc:
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selected_head_ = value & 1;
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if(drives_[0]) drives_[0]->set_head(selected_head_);
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if(drives_[1]) drives_[1]->set_head(selected_head_);
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break;
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case 0x7ffd:
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selected_drive_ = value & 1;
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set_drive(drives_[selected_drive_]);
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set_motor_on(!!(value & 0x80));
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break;
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}
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}
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uint8_t DiskROM::read(uint16_t address) {
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if(address >= 0x7ff8 && address < 0x7ffc) {
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return get_register(address);
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}
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return rom_[address & 0x3fff];
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}
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void DiskROM::run_for(HalfCycles half_cycles) {
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// Input clock is going to be 7159090/2 Mhz, but the drive controller
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// needs an 8Mhz clock, so scale up. 8000000/7159090 simplifies to
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// 800000/715909.
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controller_cycles_ += 800000 * half_cycles.as_int();
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WD::WD1770::run_for(Cycles(static_cast<int>(controller_cycles_ / 715909)));
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controller_cycles_ %= 715909;
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}
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void DiskROM::set_disk(std::shared_ptr<Storage::Disk::Disk> disk, int drive) {
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if(!drives_[drive]) {
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drives_[drive].reset(new Storage::Disk::Drive(8000000, 300, 2));
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drives_[drive]->set_head(selected_head_);
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if(drive == selected_drive_) set_drive(drives_[drive]);
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}
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drives_[drive]->set_disk(disk);
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}
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void DiskROM::set_head_load_request(bool head_load) {
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// Magic!
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set_head_loaded(head_load);
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}
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bool DiskROM::get_drive_is_ready() {
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return true;
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}
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