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CLK/Machines/MSX/DiskROM.cpp
Thomas Harte 05bcd73f82 Attempts to pull drive ownership into DiskController.
For the sake of being more intelligent as to drive clocking, hopefully. And, eventually, to support multiple drive selection.
2020-02-11 21:59:13 -05:00

75 lines
2.0 KiB
C++

//
// DiskROM.cpp
// Clock Signal
//
// Created by Thomas Harte on 07/01/2018.
// Copyright 2018 Thomas Harte. All rights reserved.
//
#include "DiskROM.hpp"
using namespace MSX;
DiskROM::DiskROM(const std::vector<uint8_t> &rom) :
WD1770(P1793),
rom_(rom) {
emplace_drives(2, 8000000, 300, 2);
set_is_double_density(true);
}
void DiskROM::write(uint16_t address, uint8_t value, bool pc_is_outside_bios) {
switch(address) {
case 0x7ff8: case 0x7ff9: case 0x7ffa: case 0x7ffb:
WD::WD1770::write(address, value);
break;
case 0x7ffc: {
const int selected_head = value & 1;
for_all_drives([selected_head] (Storage::Disk::Drive &drive, size_t index) {
drive.set_head(selected_head);
});
} break;
case 0x7ffd: {
set_drive(1 << (value & 1));
const bool drive_motor = value & 0x80;
for_all_drives([drive_motor] (Storage::Disk::Drive &drive, size_t index) {
drive.set_motor_on(drive_motor);
});
} break;
}
}
uint8_t DiskROM::read(uint16_t address) {
if(address >= 0x7ff8 && address < 0x7ffc) {
return WD::WD1770::read(address);
}
if(address == 0x7fff) {
return (get_data_request_line() ? 0x00 : 0x80) | (get_interrupt_request_line() ? 0x00 : 0x40);
}
return rom_[address & 0x3fff];
}
void DiskROM::run_for(HalfCycles half_cycles) {
// Input clock is going to be 7159090/2 Mhz, but the drive controller
// needs an 8Mhz clock, so scale up. 8000000/7159090 simplifies to
// 800000/715909.
controller_cycles_ += 800000 * half_cycles.as_integral();
WD::WD1770::run_for(Cycles(static_cast<int>(controller_cycles_ / 715909)));
controller_cycles_ %= 715909;
}
void DiskROM::set_disk(std::shared_ptr<Storage::Disk::Disk> disk, size_t drive) {
get_drive(drive).set_disk(disk);
}
void DiskROM::set_head_load_request(bool head_load) {
// Magic!
set_head_loaded(head_load);
}
void DiskROM::set_activity_observer(Activity::Observer *observer) {
for_all_drives([observer] (Storage::Disk::Drive &drive, size_t index) {
drive.set_activity_observer(observer, "Drive " + std::to_string(index), true);
});
}