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CLK/Storage/Disk/DiskController.hpp

100 lines
2.7 KiB
C++

//
// DiskController.hpp
// Clock Signal
//
// Created by Thomas Harte on 14/07/2016.
// Copyright © 2016 Thomas Harte. All rights reserved.
//
#ifndef Storage_Disk_Controller_hpp
#define Storage_Disk_Controller_hpp
#include "Drive.hpp"
#include "DigitalPhaseLockedLoop.hpp"
#include "../TimedEventLoop.hpp"
namespace Storage {
namespace Disk {
/*!
Provides the shell for emulating a disk controller — something that is connected to a disk drive and uses a
phase locked loop ('PLL') to decode a bit stream from the surface of the disk.
Partly abstract; it is expected that subclasses will provide methods to deal with receiving a newly-recognised
bit from the PLL and with crossing the index hole.
TODO: communication of head size and permissible stepping extents, appropriate simulation of gain.
*/
class Controller: public DigitalPhaseLockedLoop::Delegate, public TimedEventLoop {
protected:
/*!
Constructs a @c DiskDrive that will be run at @c clock_rate and runs its PLL at @c clock_rate*clock_rate_multiplier,
spinning inserted disks at @c revolutions_per_minute.
*/
Controller(unsigned int clock_rate, unsigned int clock_rate_multiplier, unsigned int revolutions_per_minute);
/*!
Communicates to the PLL the expected length of a bit as a fraction of a second.
*/
void set_expected_bit_length(Time bit_length);
/*!
Advances the drive by @c number_of_cycles cycles.
*/
void run_for_cycles(int number_of_cycles);
/*!
Sets the current drive.
*/
void set_drive(std::shared_ptr<Drive> drive);
void invalidate_track();
/*!
Enables or disables the disk motor.
*/
void set_motor_on(bool motor_on);
/*!
Should be implemented by subclasses; communicates each bit that the PLL recognises, also specifying
the amount of time since the index hole was last seen.
*/
virtual void process_input_bit(int value, unsigned int cycles_since_index_hole) = 0;
/*!
Should be implemented by subcalsses; communicates that the index hole has been reached.
*/
virtual void process_index_hole() = 0;
// for TimedEventLoop
virtual void process_next_event();
// to satisfy DigitalPhaseLockedLoop::Delegate
void digital_phase_locked_loop_output_bit(int value);
bool get_is_track_zero();
void step(int direction);
private:
Time _bit_length;
unsigned int _clock_rate;
unsigned int _clock_rate_multiplier;
Time _rotational_multiplier;
std::shared_ptr<DigitalPhaseLockedLoop> _pll;
std::shared_ptr<Drive> _drive;
std::shared_ptr<Track> _track;
unsigned int _cycles_since_index_hole;
inline void get_next_event();
Track::Event _current_event;
Time _time_into_track;
bool _motor_is_on;
void setup_track();
};
}
}
#endif /* DiskDrive_hpp */