mirror of
https://github.com/TomHarte/CLK.git
synced 2024-11-26 23:52:26 +00:00
112 lines
2.4 KiB
C++
112 lines
2.4 KiB
C++
//
|
|
// DMAController.cpp
|
|
// Clock Signal
|
|
//
|
|
// Created by Thomas Harte on 26/10/2019.
|
|
// Copyright © 2019 Thomas Harte. All rights reserved.
|
|
//
|
|
|
|
#include "DMAController.hpp"
|
|
|
|
#include <cstdio>
|
|
|
|
using namespace Atari::ST;
|
|
|
|
DMAController::DMAController() {
|
|
fdc_.set_delegate(this);
|
|
fdc_.set_clocking_hint_observer(this);
|
|
}
|
|
|
|
uint16_t DMAController::read(int address) {
|
|
switch(address & 7) {
|
|
// Reserved.
|
|
default: break;
|
|
|
|
// Disk controller or sector count.
|
|
case 2:
|
|
if(control_ & 0x10) {
|
|
return sector_count_;
|
|
} else {
|
|
return fdc_.get_register(control_ >> 1);
|
|
}
|
|
break;
|
|
|
|
// DMA status.
|
|
case 3:
|
|
return status_;
|
|
|
|
// DMA addressing.
|
|
case 4:
|
|
case 5:
|
|
case 6:
|
|
break;
|
|
}
|
|
return 0xffff;
|
|
}
|
|
|
|
void DMAController::write(int address, uint16_t value) {
|
|
switch(address & 7) {
|
|
// Reserved.
|
|
default: break;
|
|
|
|
// Disk controller or sector count.
|
|
case 2:
|
|
if(control_ & 0x10) {
|
|
sector_count_ = value;
|
|
} else {
|
|
fdc_.set_register(control_ >> 1, uint8_t(value));
|
|
}
|
|
break;
|
|
|
|
// DMA control; meaning is:
|
|
//
|
|
// b1, b2 = address lines for FDC access.
|
|
// b3 = 1 => HDC access; 0 => FDC access.
|
|
// b4 = 1 => sector count access; 1 => FDC access.
|
|
// b6 = 1 => DMA off; 0 => DMA on.
|
|
// b7 = 1 => FDC access; 0 => HDC access.
|
|
// b8 = 1 => write to [F/H]DC registers; 0 => read.
|
|
//
|
|
// All other bits: undefined.
|
|
// TODO: determine how b3 and b7 differ.
|
|
case 3:
|
|
control_ = value;
|
|
break;
|
|
|
|
// DMA addressing.
|
|
case 4:
|
|
case 5:
|
|
case 6:
|
|
break;
|
|
}
|
|
}
|
|
|
|
void DMAController::run_for(HalfCycles duration) {
|
|
running_time_ += duration;
|
|
fdc_.run_for(duration.flush<Cycles>());
|
|
}
|
|
|
|
void DMAController::wd1770_did_change_output(WD::WD1770 *) {
|
|
const bool old_interrupt_line = interrupt_line_;
|
|
interrupt_line_ = fdc_.get_interrupt_request_line();
|
|
if(interrupt_delegate_ && interrupt_line_ != old_interrupt_line) {
|
|
interrupt_delegate_->dma_controller_did_change_interrupt_status(this);
|
|
}
|
|
}
|
|
|
|
void DMAController::set_interrupt_delegate(InterruptDelegate *delegate) {
|
|
interrupt_delegate_ = delegate;
|
|
}
|
|
|
|
bool DMAController::get_interrupt_line() {
|
|
return interrupt_line_;
|
|
}
|
|
|
|
void DMAController::set_component_prefers_clocking(ClockingHint::Source *, ClockingHint::Preference) {
|
|
update_clocking_observer();
|
|
}
|
|
|
|
ClockingHint::Preference DMAController::preferred_clocking() {
|
|
return (fdc_.preferred_clocking() == ClockingHint::Preference::None) ? ClockingHint::Preference::None : ClockingHint::Preference::RealTime;
|
|
}
|