mirror of
https://github.com/TomHarte/CLK.git
synced 2024-11-03 23:06:18 +00:00
141 lines
3.5 KiB
C++
141 lines
3.5 KiB
C++
//
|
|
// DiskDrive.cpp
|
|
// Clock Signal
|
|
//
|
|
// Created by Thomas Harte on 14/07/2016.
|
|
// Copyright © 2016 Thomas Harte. All rights reserved.
|
|
//
|
|
|
|
#include "DiskDrive.hpp"
|
|
|
|
using namespace Storage::Disk;
|
|
|
|
Drive::Drive(unsigned int clock_rate, unsigned int clock_rate_multiplier, unsigned int revolutions_per_minute) :
|
|
_clock_rate(clock_rate * clock_rate_multiplier),
|
|
_clock_rate_multiplier(clock_rate_multiplier),
|
|
_head_position(0),
|
|
|
|
TimedEventLoop(clock_rate * clock_rate_multiplier)
|
|
{
|
|
_rotational_multiplier.length = 60;
|
|
_rotational_multiplier.clock_rate = revolutions_per_minute;
|
|
_rotational_multiplier.simplify();
|
|
}
|
|
|
|
void Drive::set_expected_bit_length(Time bit_length)
|
|
{
|
|
_bit_length = bit_length;
|
|
|
|
// this conversion doesn't need to be exact because there's a lot of variation to be taken
|
|
// account of in rotation speed, air turbulence, etc, so a direct conversion will do
|
|
int clocks_per_bit = (int)((bit_length.length * _clock_rate) / bit_length.clock_rate);
|
|
_pll.reset(new DigitalPhaseLockedLoop(clocks_per_bit, clocks_per_bit / 5, 3));
|
|
_pll->set_delegate(this);
|
|
}
|
|
|
|
void Drive::set_disk(std::shared_ptr<Disk> disk)
|
|
{
|
|
_disk = disk;
|
|
set_track(Time());
|
|
}
|
|
|
|
bool Drive::has_disk()
|
|
{
|
|
return (bool)_disk;
|
|
}
|
|
|
|
bool Drive::get_is_track_zero()
|
|
{
|
|
return _head_position == 0;
|
|
}
|
|
|
|
void Drive::step(int direction)
|
|
{
|
|
_head_position = std::max(_head_position + direction, 0);
|
|
Time extra_time = get_time_into_next_event() / _rotational_multiplier;
|
|
extra_time.simplify();
|
|
_time_into_track += extra_time;
|
|
set_track(_time_into_track);
|
|
}
|
|
|
|
void Drive::set_track(Time initial_offset)
|
|
{
|
|
_track = _disk->get_track_at_position((unsigned int)_head_position);
|
|
// TODO: probably a better implementation of the empty track?
|
|
Time offset;
|
|
if(_track && _time_into_track.length > 0)
|
|
{
|
|
Time time_found = _track->seek_to(_time_into_track).simplify();
|
|
offset = (_time_into_track - time_found).simplify();
|
|
_time_into_track = time_found;
|
|
}
|
|
else
|
|
{
|
|
offset = _time_into_track;
|
|
_time_into_track.set_zero();
|
|
}
|
|
|
|
reset_timer();
|
|
get_next_event();
|
|
reset_timer_to_offset(offset * _rotational_multiplier);
|
|
}
|
|
|
|
void Drive::run_for_cycles(int number_of_cycles)
|
|
{
|
|
if(has_disk())
|
|
{
|
|
number_of_cycles *= _clock_rate_multiplier;
|
|
while(number_of_cycles)
|
|
{
|
|
int cycles_until_next_event = (int)get_cycles_until_next_event();
|
|
int cycles_to_run_for = std::min(cycles_until_next_event, number_of_cycles);
|
|
_cycles_since_index_hole += (unsigned int)cycles_to_run_for;
|
|
number_of_cycles -= cycles_to_run_for;
|
|
_pll->run_for_cycles(cycles_to_run_for);
|
|
TimedEventLoop::run_for_cycles(cycles_to_run_for);
|
|
}
|
|
}
|
|
}
|
|
|
|
#pragma mark - Track timed event loop
|
|
|
|
void Drive::get_next_event()
|
|
{
|
|
if(_track)
|
|
_current_event = _track->get_next_event();
|
|
else
|
|
{
|
|
_current_event.length.length = 1;
|
|
_current_event.length.clock_rate = 1;
|
|
_current_event.type = Track::Event::IndexHole;
|
|
}
|
|
|
|
// divide interval, which is in terms of a rotation of the disk, by rotation speed, and
|
|
// convert it into revolutions per second
|
|
set_next_event_time_interval(_current_event.length * _rotational_multiplier);
|
|
}
|
|
|
|
void Drive::process_next_event()
|
|
{
|
|
switch(_current_event.type)
|
|
{
|
|
case Track::Event::FluxTransition:
|
|
_pll->add_pulse();
|
|
_time_into_track += _current_event.length;
|
|
break;
|
|
case Track::Event::IndexHole:
|
|
_cycles_since_index_hole = 0;
|
|
_time_into_track.set_zero();
|
|
process_index_hole();
|
|
break;
|
|
}
|
|
get_next_event();
|
|
}
|
|
|
|
#pragma mark - PLL delegate
|
|
|
|
void Drive::digital_phase_locked_loop_output_bit(int value)
|
|
{
|
|
process_input_bit(value, _cycles_since_index_hole);
|
|
}
|