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30 * EventQueue interfaces
43 #include "sim/host.hh" // for Tick
45 #include "base/fast_alloc.hh"
46 #include "sim/serialize.hh"
47 #include "base/trace.hh"
49 class EventQueue; // forward declaration
52 * An item on an event queue. The action caused by a given
53 * event is specified by deriving a subclass and overriding the
54 * process() member function.
56 class Event : public Serializeable, public FastAlloc
58 friend class EventQueue;
61 /// queue to which this event belongs (though it may or may not be
62 /// scheduled on this queue yet)
67 Tick _when; //!< timestamp when event should be processed
68 int _priority; //!< event priority
79 bool getFlags(Flags f) const { return (_flags & f) == f; }
80 void setFlags(Flags f) { _flags |= f; }
81 void clearFlags(Flags f) { _flags &= ~f; }
84 EventQueue *theQueue() const { return queue; }
87 Tick when_created; //!< Keep track of creation time For debugging
88 Tick when_scheduled; //!< Keep track of creation time For debugging
90 virtual void trace(const char *action); //!< trace event activity
92 void trace(const char *) {}
95 unsigned annotated_value;
99 static const std::string defaultName;
103 * @param queue that the event gets scheduled on
105 Event(EventQueue *q, int p = 0)
106 : Serializeable(defaultName), queue(q), next(NULL),
107 _priority(p), _flags(None),
109 when_created(curTick), when_scheduled(0),
117 /// Determine if the current event is scheduled
118 bool scheduled() const { return getFlags(Scheduled); }
120 /// Schedule the event with the current priority or default priority
121 void schedule(Tick t);
123 /// Schedule the event with a specific priority
124 void schedule(Tick t, int priority);
126 /// Reschedule the event with the current priority
127 void reschedule(Tick t);
129 /// Reschedule the event with a specific priority
130 void reschedule(Tick t, int priority);
132 /// Remove the event from the current schedule
135 /// Return a C string describing the event. This string should
136 /// *not* be dynamically allocated; just a const char array
137 /// describing the event class.
138 virtual const char *description();
140 /// Dump the current event data
144 * This member function is invoked when the event is processed
145 * (occurs). There is no default implementation; each subclass
146 * must provide its own implementation. The event is not
147 * automatically deleted after it is processed (to allow for
148 * statically allocated event objects).
150 * If the AutoDestroy flag is set, the object is deleted once it
153 virtual void process() = 0;
155 void annotate(unsigned value) { annotated_value = value; };
156 unsigned annotation() { return annotated_value; }
158 /// Squash the current event
159 void squash() { setFlags(Squashed); }
161 /// Check whether the event is squashed
162 bool squashed() { return getFlags(Squashed); }
164 /// Get the time that the event is scheduled
165 Tick when() const { return _when; }
167 /// Get the event priority
168 int priority() const { return _priority; }
170 struct priority_compare :
171 public std::binary_function<Event *, Event *, bool>
173 bool operator()(const Event *l, const Event *r) const {
174 return l->when() >= r->when() || l->priority() >= r->priority();
179 template <class T, void (T::* F)()>
181 DelayFunction(Tick when, T *object)
183 class DelayEvent : public Event
189 DelayEvent(Tick when, T *o)
190 : Event(&mainEventQueue), object(o)
191 { setFlags(AutoDestroy); schedule(when); }
192 void process() { (object->*F)(); }
193 const char *description() { return "delay"; }
196 new DelayEvent(when, object);
200 * Queue of events sorted in time order
202 class EventQueue : public Serializeable
207 void insert(Event *event);
208 void remove(Event *event);
213 EventQueue(const std::string &n)
214 : Serializeable(n), head(NULL)
217 // schedule the given event on this queue
218 void schedule(Event *ev);
219 void deschedule(Event *ev);
220 void reschedule(Event *ev);
222 Tick nextTick() { return head->when(); }
225 // process all events up to the given timestamp. we inline a
226 // quick test to see if there are any events to process; if so,
227 // call the internal out-of-line version to process them all.
228 void serviceEvents(Tick when) {
230 if (nextTick() > when)
233 assert(head->when() >= when && "event scheduled in the past");
238 // default: process all events up to 'now' (curTick)
239 void serviceEvents() { serviceEvents(curTick); }
241 // return true if no events are queued
242 bool empty() { return head == NULL; }
246 Tick nextEventTime() { return empty() ? curTick : head->when(); }
248 virtual void nameChildren();
249 virtual void serialize();
253 //////////////////////
257 // can't put these inside declaration due to circular dependence
258 // between Event and EventQueue classes.
260 //////////////////////
262 // schedule at specified time (place on event queue specified via
265 Event::schedule(Tick t)
267 assert(!scheduled());
270 when_scheduled = curTick;
273 queue->schedule(this);
277 Event::schedule(Tick t, int p)
288 clearFlags(Squashed);
289 clearFlags(Scheduled);
290 queue->deschedule(this);
294 Event::reschedule(Tick t)
297 clearFlags(Squashed);
300 when_scheduled = curTick;
303 queue->reschedule(this);
307 Event::reschedule(Tick t, int p)
314 EventQueue::schedule(Event *event)
318 event->trace("scheduled");
322 EventQueue::deschedule(Event *event)
326 event->trace("descheduled");
330 EventQueue::reschedule(Event *event)
335 event->trace("rescheduled");
339 //////////////////////
343 // Events on this queue are processed at the *beginning* of each
344 // cycle, before the pipeline simulation is performed.
346 // defined in eventq.cc
348 //////////////////////
349 extern EventQueue mainEventQueue;
351 #endif // __EVENTQ_HH__