From 99122efbbc81a3da886a962d3812e5b340a67d11 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Wed, 15 Jan 2020 23:29:52 -0500
Subject: [PATCH] Adds a slight cool-down period on end-of-rotation.
Along with the corresponding inactive transition of the ready signal.
---
Storage/Disk/Drive.cpp | 69 +++++++++++++++++++++++++++++++-----------
Storage/Disk/Drive.hpp | 3 ++
2 files changed, 54 insertions(+), 18 deletions(-)
diff --git a/Storage/Disk/Drive.cpp b/Storage/Disk/Drive.cpp
index a281c3a06..261ba711d 100644
--- a/Storage/Disk/Drive.cpp
+++ b/Storage/Disk/Drive.cpp
@@ -68,7 +68,7 @@ bool Drive::has_disk() const {
}
ClockingHint::Preference Drive::preferred_clocking() {
- return (!motor_input_is_on_ || !has_disk_) ? ClockingHint::Preference::None : ClockingHint::Preference::JustInTime;
+ return (!has_disk_ || (time_until_motor_transition == Cycles(0) && !disk_is_rotating_)) ? ClockingHint::Preference::None : ClockingHint::Preference::JustInTime;
}
bool Drive::get_is_track_zero() const {
@@ -146,22 +146,29 @@ bool Drive::get_is_ready() const {
}
void Drive::set_motor_on(bool motor_is_on) {
- if(motor_input_is_on_ != motor_is_on) {
- motor_input_is_on_ = motor_is_on;
+ // Do nothing if the input hasn't changed.
+ if(motor_input_is_on_ == motor_is_on) return;
+ motor_input_is_on_ = motor_is_on;
- if(observer_) {
- observer_->set_drive_motor_status(drive_name_, motor_input_is_on_);
- if(announce_motor_led_) {
- observer_->set_led_status(drive_name_, motor_input_is_on_);
- }
- }
-
- if(!motor_is_on) {
- ready_index_count_ = 0;
- if(disk_) disk_->flush_tracks();
- }
- update_clocking_observer();
+ // If this now means that the input and the actual state are in harmony,
+ // cancel any planned change and stop.
+ if(disk_is_rotating_ == motor_is_on) {
+ time_until_motor_transition = Cycles(0);
+ return;
}
+
+ // If this is a transition to on, start immediately.
+ // TODO: spin-up?
+ // TODO: momentum.
+ if(motor_is_on) {
+ set_disk_is_rotating(true);
+ return;
+ }
+
+ // This is a transition from on to off. Simulate momentum (ha!)
+ // by delaying the time until complete standstill.
+ if(time_until_motor_transition == Cycles(0))
+ time_until_motor_transition = get_input_clock_rate();
}
bool Drive::get_motor_on() const {
@@ -185,7 +192,16 @@ void Drive::run_for(const Cycles cycles) {
// Assumed: the index pulse pulses even if the drive has stopped spinning.
index_pulse_remaining_ = std::max(index_pulse_remaining_ - cycles, Cycles(0));
- if(motor_input_is_on_) {
+ if(time_until_motor_transition > Cycles(0)) {
+ if(time_until_motor_transition > cycles) {
+ time_until_motor_transition -= cycles;
+ } else {
+ time_until_motor_transition = Cycles(0);
+ set_disk_is_rotating(!disk_is_rotating_);
+ }
+ }
+
+ if(disk_is_rotating_) {
if(has_disk_) {
Time zero(0);
@@ -400,6 +416,23 @@ bool Drive::is_writing() const {
return !is_reading_;
}
+void Drive::set_disk_is_rotating(bool is_rotating) {
+ disk_is_rotating_ = is_rotating;
+
+ if(observer_) {
+ observer_->set_drive_motor_status(drive_name_, motor_input_is_on_);
+ if(announce_motor_led_) {
+ observer_->set_led_status(drive_name_, motor_input_is_on_);
+ }
+ }
+
+ if(!is_rotating) {
+ ready_index_count_ = 0;
+ if(disk_) disk_->flush_tracks();
+ }
+ update_clocking_observer();
+}
+
void Drive::set_activity_observer(Activity::Observer *observer, const std::string &name, bool add_motor_led) {
observer_ = observer;
announce_motor_led_ = add_motor_led;
@@ -407,11 +440,11 @@ void Drive::set_activity_observer(Activity::Observer *observer, const std::strin
drive_name_ = name;
observer->register_drive(drive_name_);
- observer->set_drive_motor_status(drive_name_, motor_input_is_on_);
+ observer->set_drive_motor_status(drive_name_, disk_is_rotating_);
if(add_motor_led) {
observer->register_led(drive_name_);
- observer->set_led_status(drive_name_, motor_input_is_on_);
+ observer->set_led_status(drive_name_, disk_is_rotating_);
}
}
}
diff --git a/Storage/Disk/Drive.hpp b/Storage/Disk/Drive.hpp
index d2b3f8a81..c568a399f 100644
--- a/Storage/Disk/Drive.hpp
+++ b/Storage/Disk/Drive.hpp
@@ -214,6 +214,9 @@ class Drive: public ClockingHint::Source, public TimedEventLoop {
// Motor control state.
bool motor_input_is_on_ = false;
+ bool disk_is_rotating_ = false;
+ Cycles time_until_motor_transition;
+ void set_disk_is_rotating(bool);
// Current state of the index pulse output.
Cycles index_pulse_remaining_;