174 lines
4.6 KiB
Text
174 lines
4.6 KiB
Text
/*
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* This file is part of libsidplayfp, a SID player engine.
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*
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* Copyright 2011-2013 Leandro Nini <drfiemost@users.sourceforge.net>
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* Copyright 2007-2010 Antti Lankila
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* Copyright 2001 Simon White
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#ifndef EVENT_H
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#define EVENT_H
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#include <stdint.h>
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#include "sidplayfp/siddefs.h"
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typedef int_fast64_t event_clock_t;
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/**
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* C64 system runs actions at system clock high and low
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* states. The PHI1 corresponds to the auxiliary chip activity
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* and PHI2 to CPU activity. For any clock, PHI1s are before
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* PHI2s.
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*/
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typedef enum {EVENT_CLOCK_PHI1 = 0, EVENT_CLOCK_PHI2 = 1} event_phase_t;
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/**
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* Event scheduler (based on alarm from Vice). Created in 2001 by Simon A.
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* White.
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*
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* Optimized EventScheduler and corresponding Event class by Antti S. Lankila
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* in 2009.
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*
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* @author Antti Lankila
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*/
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class SID_EXTERN Event
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{
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friend class EventScheduler;
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private:
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/**
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* The next event in sequence.
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*/
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Event *next;
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/**
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* The clock this event fires.
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*/
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event_clock_t triggerTime;
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/**
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* Describe event for humans.
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*/
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const char * const m_name;
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public:
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/**
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* Events are used for delayed execution. Name is
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* not used by code, but is useful for debugging.
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*
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* @param name Descriptive string of the event.
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*/
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Event(const char * const name) :
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m_name(name) {}
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/**
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* Event code to be executed. Events are allowed to safely
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* reschedule themselves with the EventScheduler during
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* invocations.
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*/
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virtual void event() = 0;
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protected:
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~Event() {}
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};
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/**
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* Fast EventScheduler, which maintains a linked list of Events.
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* This scheduler takes neglible time even when it is used to
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* schedule events for nearly every clock.
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*
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* Events occur on an internal clock which is 2x the visible clock.
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* The visible clock is divided to two phases called phi1 and phi2.
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*
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* The phi1 clocks are used by VIC and CIA chips, phi2 clocks by CPU.
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*
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* Scheduling an event for a phi1 clock when system is in phi2 causes the
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* event to be moved to the next phi1 cycle. Correspondingly, requesting
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* a phi1 time when system is in phi2 returns the value of the next phi1.
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*
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* @author Antti S. Lankila
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*/
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class EventContext
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{
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public:
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/**
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* Cancel the specified event.
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*
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* @param event the event to cancel
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*/
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virtual void cancel(Event &event) = 0;
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/**
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* Add event to pending queue.
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*
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* At PHI2, specify cycles=0 and Phase=PHI1 to fire on the very next PHI1.
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*
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* @param event the event to add
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* @param cycles how many cycles from now to fire
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* @param phase the phase when to fire the event
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*/
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virtual void schedule(Event &event, event_clock_t cycles,
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event_phase_t phase) = 0;
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/**
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* Add event to pending queue in the same phase as current event.
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*
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* @param event the event to add
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* @param cycles how many cycles from now to fire
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*/
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virtual void schedule(Event &event, event_clock_t cycles) = 0;
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/**
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* Is the event pending in this scheduler?
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*
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* @param event the event
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* @return true when pending
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*/
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virtual bool isPending(Event &event) const = 0;
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/**
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* Get time with respect to a specific clock phase.
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*
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* @param phase the phase
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* @return the time according to specified phase.
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*/
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virtual event_clock_t getTime(event_phase_t phase) const = 0;
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/**
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* Get clocks since specified clock in given phase.
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*
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* @param clock the time to compare to
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* @param phase the phase to comapre to
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* @return the time between specified clock and now
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*/
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virtual event_clock_t getTime(event_clock_t clock, event_phase_t phase) const = 0;
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/**
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* Return current clock phase.
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*
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* @return The current phase
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*/
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virtual event_phase_t phase() const = 0;
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protected:
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~EventContext() {}
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};
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#endif // EVENT_H
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