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Provides an implementation of Drive's new interface.

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Mostly lifted from DiskController. `set_disk_with_track` has been withdrawn in favour of providing a suitable wrapper `Disk` subclass, as being an unnecessary complexity and intermingling of concerns.
This commit is contained in:
Thomas Harte 2017-09-10 17:33:01 -04:00
parent 6075064400
commit a4e275e1fc
2 changed files with 172 additions and 48 deletions
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178
Storage/Disk/Drive.cpp
View File

@ -7,7 +7,11 @@
//
#include "Drive.hpp"
#include "UnformattedTrack.hpp"
#include <algorithm>
#include <cassert>
using namespace Storage::Disk;
@ -18,16 +22,13 @@ Drive::Drive(unsigned int input_clock_rate, int revolutions_per_minute):
void Drive::set_disk(const std::shared_ptr<Disk> &disk) {
disk_ = disk;
track_ = nullptr;
has_disk_ = !!disk_;
update_sleep_observer();
}
void Drive::set_disk_with_track(const std::shared_ptr<Track> &track) {
disk_ = nullptr;
track_ = track;
has_disk_ = !!track_;
invalidate_track();
update_sleep_observer();
// TODO: implement ready properly.
is_ready_ = true;
}
bool Drive::has_disk() {
@ -46,8 +47,15 @@ void Drive::step(int direction) {
int old_head_position = head_position_;
head_position_ = std::max(head_position_ + direction, 0);
// If the head moved and this drive has a real disk in it, flush the old track.
if(head_position_ != old_head_position && disk_ != nullptr) {
// If the head moved, flush the old track.
if(head_position_ != old_head_position) {
track_ = nullptr;
}
}
void Drive::set_head(unsigned int head) {
if(head != head_) {
head_ = head;
track_ = nullptr;
}
}
@ -55,34 +63,19 @@ void Drive::step(int direction) {
Storage::Time Drive::get_time_into_track() {
// `result` will initially be amount of time since the index hole was seen as a
// proportion of a second; convert it into proportion of a rotation, simplify and return.
Time result(cycles_since_index_hole_, 8000000);
Time result(cycles_since_index_hole_, (int)get_input_clock_rate());
result /= rotational_multiplier_;
result.simplify();
return result;
}
void Drive::set_head(unsigned int head) {
head_ = head;
}
bool Drive::get_is_read_only() {
if(disk_) return disk_->get_is_read_only();
return true;
}
bool Drive::get_is_ready() {
// TODO: a real test for this.
return disk_ != nullptr;
}
std::shared_ptr<Track> Drive::get_track() {
if(disk_) return disk_->get_track_at_position(head_, (unsigned int)head_position_);
if(track_) return track_;
return nullptr;
}
void Drive::set_track(const std::shared_ptr<Track> &track) {
if(disk_) disk_->set_track_at_position(head_, (unsigned int)head_position_, track);
return is_ready_;
}
void Drive::set_motor_on(bool motor_is_on) {
@ -90,9 +83,136 @@ void Drive::set_motor_on(bool motor_is_on) {
update_sleep_observer();
}
void Drive::process_next_event() {
if(event_delegate_) event_delegate_->process_event(current_event_);
void Drive::run_for(const Cycles cycles) {
Time zero(0);
if(has_disk_ && motor_is_on_) {
// Grab a new track if not already in possession of one.
if(!track_) setup_track();
int number_of_cycles = cycles.as_int();
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);
if(!is_reading_ && cycles_until_bits_written_ > zero) {
int write_cycles_target = (int)cycles_until_bits_written_.get_unsigned_int();
if(cycles_until_bits_written_.length % cycles_until_bits_written_.clock_rate) write_cycles_target++;
cycles_to_run_for = std::min(cycles_to_run_for, write_cycles_target);
}
cycles_since_index_hole_ += (unsigned int)cycles_to_run_for;
number_of_cycles -= cycles_to_run_for;
if(is_reading_) {
if(event_delegate_) event_delegate_->advance(Cycles(cycles_to_run_for));
} else {
if(cycles_until_bits_written_ > zero) {
Storage::Time cycles_to_run_for_time(cycles_to_run_for);
if(cycles_until_bits_written_ <= cycles_to_run_for_time) {
if(event_delegate_) event_delegate_->process_write_completed();
if(cycles_until_bits_written_ <= cycles_to_run_for_time)
cycles_until_bits_written_.set_zero();
else
cycles_until_bits_written_ -= cycles_to_run_for_time;
} else {
cycles_until_bits_written_ -= cycles_to_run_for_time;
}
}
}
TimedEventLoop::run_for(Cycles(cycles_to_run_for));
}
}
}
void Drive::run_for(const Cycles cycles) {
#pragma mark - Track timed event loop
void Drive::get_next_event(const Time &duration_already_passed) {
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 single rotation of the disk, by rotation speed to
// convert it into revolutions per second; this is achieved by multiplying by rotational_multiplier_
assert(current_event_.length <= Time(1) && current_event_.length >= Time(0));
Time interval = (current_event_.length - duration_already_passed) * rotational_multiplier_;
set_next_event_time_interval(interval);
}
void Drive::process_next_event() {
// TODO: ready test here.
if(event_delegate_) event_delegate_->process_event(current_event_);
get_next_event(Time(0));
}
#pragma mark - Track management
std::shared_ptr<Track> Drive::get_track() {
if(disk_) return disk_->get_track_at_position(head_, (unsigned int)head_position_);
return nullptr;
}
void Drive::set_track(const std::shared_ptr<Track> &track) {
if(disk_) disk_->set_track_at_position(head_, (unsigned int)head_position_, track);
}
void Drive::setup_track() {
track_ = get_track();
if(!track_) {
track_.reset(new UnformattedTrack);
}
Time offset;
Time track_time_now = get_time_into_track();
assert(track_time_now >= Time(0) && current_event_.length <= Time(1));
Time time_found = track_->seek_to(track_time_now);
assert(time_found >= Time(0) && time_found <= track_time_now);
offset = track_time_now - time_found;
get_next_event(offset);
}
void Drive::invalidate_track() {
track_ = nullptr;
}
#pragma mark - Writing
void Drive::begin_writing(Time bit_length, bool clamp_to_index_hole) {
is_reading_ = false;
clamp_writing_to_index_hole_ = clamp_to_index_hole;
write_segment_.length_of_a_bit = bit_length / rotational_multiplier_;
write_segment_.data.clear();
write_segment_.number_of_bits = 0;
write_start_time_ = get_time_into_track();
}
void Drive::write_bit(bool value) {
bool needs_new_byte = !(write_segment_.number_of_bits&7);
if(needs_new_byte) write_segment_.data.push_back(0);
if(value) write_segment_.data[write_segment_.number_of_bits >> 3] |= 0x80 >> (write_segment_.number_of_bits & 7);
write_segment_.number_of_bits++;
cycles_until_bits_written_ += cycles_per_bit_;
}
void Drive::end_writing() {
is_reading_ = true;
if(!patched_track_) {
// Avoid creating a new patched track if this one is already patched
patched_track_ = std::dynamic_pointer_cast<PCMPatchedTrack>(track_);
if(!patched_track_) {
patched_track_.reset(new PCMPatchedTrack(track_));
}
}
patched_track_->add_segment(write_start_time_, write_segment_, clamp_writing_to_index_hole_);
cycles_since_index_hole_ %= get_input_clock_rate();
invalidate_track();
}

42
Storage/Disk/Drive.hpp
View File

@ -30,11 +30,6 @@ class Drive: public Sleeper, public TimedEventLoop {
*/
void set_disk(const std::shared_ptr<Disk> &disk);
/*!
Replaces whatever is in the drive with a disk that contains endless copies of @c track.
*/
void set_disk_with_track(const std::shared_ptr<Track> &track);
/*!
@returns @c true if a disk is currently inserted; @c false otherwise.
*/
@ -61,16 +56,6 @@ class Drive: public Sleeper, public TimedEventLoop {
*/
bool get_is_read_only();
/*!
@returns the track underneath the current head at the location now stepped to.
*/
std::shared_ptr<Track> get_track();
/*!
Attempts to set @c track as the track underneath the current head at the location now stepped to.
*/
void set_track(const std::shared_ptr<Track> &track);
/*!
@returns @c true if the drive is ready; @c false otherwise.
*/
@ -95,7 +80,7 @@ class Drive: public Sleeper, public TimedEventLoop {
@param clamp_to_index_hole If @c true then writing will automatically be truncated by
the index hole. Writing will continue over the index hole otherwise.
*/
void begin_writing(bool clamp_to_index_hole);
void begin_writing(Time bit_length, bool clamp_to_index_hole);
/*!
Writes the bit @c value as the next in the PCM stream initiated by @c begin_writing.
@ -125,6 +110,9 @@ class Drive: public Sleeper, public TimedEventLoop {
If the controller provides further bits now then there will be no gap in written data.
*/
virtual void process_write_completed() {}
/// Informs the delegate of the passing of @c cycles.
virtual void advance(const Cycles cycles) {}
};
/// Sets the current event delegate.
@ -134,7 +122,7 @@ class Drive: public Sleeper, public TimedEventLoop {
bool is_sleeping();
private:
// Drives [usually] contain an entire disk; from that a certain track
// Drives contain an entire disk; from that a certain track
// will be currently under the head.
std::shared_ptr<Disk> disk_;
std::shared_ptr<Track> track_;
@ -158,8 +146,8 @@ class Drive: public Sleeper, public TimedEventLoop {
// If the drive is not currently reading then it is writing. While writing
// it can optionally be told to clamp to the index hole.
bool is_reading_;
bool clamp_writing_to_index_hole_;
bool is_reading_ = false;
bool clamp_writing_to_index_hole_ = false;
// If writing is occurring then the drive will be accumulating a write segment,
// for addition to a patched track.
@ -167,6 +155,9 @@ class Drive: public Sleeper, public TimedEventLoop {
PCMSegment write_segment_;
Time write_start_time_;
// Indicates drive ready state.
bool is_ready_ = false;
// Maintains appropriate counting to know when to indicate that writing
// is complete.
Time cycles_until_bits_written_;
@ -182,6 +173,19 @@ class Drive: public Sleeper, public TimedEventLoop {
// The target (if any) for track events.
EventDelegate *event_delegate_ = nullptr;
/*!
@returns the track underneath the current head at the location now stepped to.
*/
std::shared_ptr<Track> get_track();
/*!
Attempts to set @c track as the track underneath the current head at the location now stepped to.
*/
void set_track(const std::shared_ptr<Track> &track);
void setup_track();
void invalidate_track();
};