190 lines
5.0 KiB
C++
190 lines
5.0 KiB
C++
/*
|
|
* This file is part of libsidplayfp, a SID player engine.
|
|
*
|
|
* Copyright (C) 2011-2015 Leandro Nini
|
|
* Copyright (C) 2009 Antti S. Lankila
|
|
* Copyright (C) 2001 Simon White
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#ifndef EVENTSCHEDULER_H
|
|
#define EVENTSCHEDULER_H
|
|
|
|
#include "Event.h"
|
|
|
|
#include "sidcxx11.h"
|
|
|
|
|
|
namespace libsidplayfp
|
|
{
|
|
|
|
/**
|
|
* C64 system runs actions at system clock high and low
|
|
* states. The PHI1 corresponds to the auxiliary chip activity
|
|
* and PHI2 to CPU activity. For any clock, PHI1s are before
|
|
* PHI2s.
|
|
*/
|
|
typedef enum
|
|
{
|
|
EVENT_CLOCK_PHI1 = 0,
|
|
EVENT_CLOCK_PHI2 = 1
|
|
} event_phase_t;
|
|
|
|
|
|
/**
|
|
* Fast EventScheduler, which maintains a linked list of Events.
|
|
* This scheduler takes neglible time even when it is used to
|
|
* schedule events for nearly every clock.
|
|
*
|
|
* Events occur on an internal clock which is 2x the visible clock.
|
|
* The visible clock is divided to two phases called phi1 and phi2.
|
|
*
|
|
* The phi1 clocks are used by VIC and CIA chips, phi2 clocks by CPU.
|
|
*
|
|
* Scheduling an event for a phi1 clock when system is in phi2 causes the
|
|
* event to be moved to the next phi1 cycle. Correspondingly, requesting
|
|
* a phi1 time when system is in phi2 returns the value of the next phi1.
|
|
*/
|
|
class EventScheduler
|
|
{
|
|
private:
|
|
/// The first event of the chain.
|
|
Event *firstEvent;
|
|
|
|
/// EventScheduler's current clock.
|
|
event_clock_t currentTime;
|
|
|
|
private:
|
|
/**
|
|
* Scan the event queue and schedule event for execution.
|
|
*
|
|
* @param event The event to add
|
|
*/
|
|
void schedule(Event &event)
|
|
{
|
|
// find the right spot where to tuck this new event
|
|
Event **scan = &firstEvent;
|
|
for (;;)
|
|
{
|
|
if (*scan == nullptr || (*scan)->triggerTime > event.triggerTime)
|
|
{
|
|
event.next = *scan;
|
|
*scan = &event;
|
|
break;
|
|
}
|
|
scan = &((*scan)->next);
|
|
}
|
|
}
|
|
|
|
public:
|
|
EventScheduler() :
|
|
firstEvent(nullptr),
|
|
currentTime(0) {}
|
|
|
|
/**
|
|
* Add event to pending queue.
|
|
*
|
|
* At PHI2, specify cycles=0 and Phase=PHI1 to fire on the very next PHI1.
|
|
*
|
|
* @param event the event to add
|
|
* @param cycles how many cycles from now to fire
|
|
* @param phase the phase when to fire the event
|
|
*/
|
|
void schedule(Event &event, unsigned int cycles, event_phase_t phase)
|
|
{
|
|
// this strange formulation always selects the next available slot regardless of specified phase.
|
|
event.triggerTime = currentTime + ((currentTime & 1) ^ phase) + (cycles << 1);
|
|
schedule(event);
|
|
}
|
|
|
|
/**
|
|
* Add event to pending queue in the same phase as current event.
|
|
*
|
|
* @param event the event to add
|
|
* @param cycles how many cycles from now to fire
|
|
*/
|
|
void schedule(Event &event, unsigned int cycles)
|
|
{
|
|
event.triggerTime = currentTime + (cycles << 1);
|
|
schedule(event);
|
|
}
|
|
|
|
/**
|
|
* Cancel event if pending.
|
|
*
|
|
* @param event the event to cancel
|
|
*/
|
|
void cancel(Event &event);
|
|
|
|
/**
|
|
* Cancel all pending events and reset time.
|
|
*/
|
|
void reset();
|
|
|
|
/**
|
|
* Fire next event, advance system time to that event.
|
|
*/
|
|
void clock()
|
|
{
|
|
Event &event = *firstEvent;
|
|
firstEvent = firstEvent->next;
|
|
currentTime = event.triggerTime;
|
|
event.event();
|
|
}
|
|
|
|
/**
|
|
* Check if an event is in the queue.
|
|
*
|
|
* @param event the event
|
|
* @return true when pending
|
|
*/
|
|
bool isPending(Event &event) const;
|
|
|
|
/**
|
|
* Get time with respect to a specific clock phase.
|
|
*
|
|
* @param phase the phase
|
|
* @return the time according to specified phase.
|
|
*/
|
|
event_clock_t getTime(event_phase_t phase) const
|
|
{
|
|
return (currentTime + (phase ^ 1)) >> 1;
|
|
}
|
|
|
|
/**
|
|
* Get clocks since specified clock in given phase.
|
|
*
|
|
* @param clock the time to compare to
|
|
* @param phase the phase to comapre to
|
|
* @return the time between specified clock and now
|
|
*/
|
|
event_clock_t getTime(event_clock_t clock, event_phase_t phase) const
|
|
{
|
|
return getTime(phase) - clock;
|
|
}
|
|
|
|
/**
|
|
* Return current clock phase.
|
|
*
|
|
* @return The current phase
|
|
*/
|
|
event_phase_t phase() const { return static_cast<event_phase_t>(currentTime & 1); }
|
|
};
|
|
|
|
}
|
|
|
|
#endif // EVENTSCHEDULER_H
|