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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
80 bool getFlags(Flags f) const { return (_flags & f) == f; }
81 void setFlags(Flags f) { _flags |= f; }
82 void clearFlags(Flags f) { _flags &= ~f; }
85 EventQueue *theQueue() const { return queue; }
88 Tick when_created; //!< Keep track of creation time For debugging
89 Tick when_scheduled; //!< Keep track of creation time For debugging
91 virtual void trace(const char *action); //!< trace event activity
93 void trace(const char *) {}
96 unsigned annotated_value;
102 * @param queue that the event gets scheduled on
104 Event(EventQueue *q, int p = 0)
105 : queue(q), next(NULL), _priority(p), _flags(None),
107 when_created(curTick), when_scheduled(0),
115 virtual std::string name() const {
116 return csprintf("Event_%x", (uintptr_t)this);
119 /// Determine if the current event is scheduled
120 bool scheduled() const { return getFlags(Scheduled); }
122 /// Schedule the event with the current priority or default priority
123 void schedule(Tick t);
125 /// Schedule the event with a specific priority
126 void schedule(Tick t, int priority);
128 /// Reschedule the event with the current priority
129 void reschedule(Tick t);
131 /// Reschedule the event with a specific priority
132 void reschedule(Tick t, int priority);
134 /// Remove the event from the current schedule
137 /// Return a C string describing the event. This string should
138 /// *not* be dynamically allocated; just a const char array
139 /// describing the event class.
140 virtual const char *description();
142 /// Dump the current event data
146 * This member function is invoked when the event is processed
147 * (occurs). There is no default implementation; each subclass
148 * must provide its own implementation. The event is not
149 * automatically deleted after it is processed (to allow for
150 * statically allocated event objects).
152 * If the AutoDestroy flag is set, the object is deleted once it
155 virtual void process() = 0;
157 void annotate(unsigned value) { annotated_value = value; };
158 unsigned annotation() { return annotated_value; }
160 /// Squash the current event
161 void squash() { setFlags(Squashed); }
163 /// Check whether the event is squashed
164 bool squashed() { return getFlags(Squashed); }
166 /// Get the time that the event is scheduled
167 Tick when() const { return _when; }
169 /// Get the event priority
170 int priority() const { return _priority; }
172 struct priority_compare :
173 public std::binary_function<Event *, Event *, bool>
175 bool operator()(const Event *l, const Event *r) const {
176 return l->when() >= r->when() || l->priority() >= r->priority();
180 virtual void serialize(std::ostream &os);
181 virtual void unserialize(Checkpoint *cp, const std::string §ion);
184 template <class T, void (T::* F)()>
186 DelayFunction(Tick when, T *object)
188 class DelayEvent : public Event
194 DelayEvent(Tick when, T *o)
195 : Event(&mainEventQueue), object(o)
196 { setFlags(AutoDestroy); schedule(when); }
197 void process() { (object->*F)(); }
198 const char *description() { return "delay"; }
201 new DelayEvent(when, object);
205 * Queue of events sorted in time order
207 class EventQueue : public Serializeable
215 void insert(Event *event);
216 void remove(Event *event);
221 EventQueue(const std::string &n)
222 : objName(n), head(NULL)
225 virtual std::string name() const { return objName; }
227 // schedule the given event on this queue
228 void schedule(Event *ev);
229 void deschedule(Event *ev);
230 void reschedule(Event *ev);
232 Tick nextTick() { return head->when(); }
235 // process all events up to the given timestamp. we inline a
236 // quick test to see if there are any events to process; if so,
237 // call the internal out-of-line version to process them all.
238 void serviceEvents(Tick when) {
240 if (nextTick() > when)
243 assert(head->when() >= when && "event scheduled in the past");
248 // default: process all events up to 'now' (curTick)
249 void serviceEvents() { serviceEvents(curTick); }
251 // return true if no events are queued
252 bool empty() { return head == NULL; }
256 Tick nextEventTime() { return empty() ? curTick : head->when(); }
258 virtual void serialize(std::ostream &os);
259 virtual void unserialize(Checkpoint *cp, const std::string §ion);
263 //////////////////////
267 // can't put these inside declaration due to circular dependence
268 // between Event and EventQueue classes.
270 //////////////////////
272 // schedule at specified time (place on event queue specified via
275 Event::schedule(Tick t)
277 assert(!scheduled());
280 when_scheduled = curTick;
283 queue->schedule(this);
287 Event::schedule(Tick t, int p)
298 clearFlags(Squashed);
299 clearFlags(Scheduled);
300 queue->deschedule(this);
304 Event::reschedule(Tick t)
307 clearFlags(Squashed);
310 when_scheduled = curTick;
313 queue->reschedule(this);
317 Event::reschedule(Tick t, int p)
324 EventQueue::schedule(Event *event)
328 event->trace("scheduled");
332 EventQueue::deschedule(Event *event)
336 event->trace("descheduled");
340 EventQueue::reschedule(Event *event)
345 event->trace("rescheduled");
349 //////////////////////
353 // Events on this queue are processed at the *beginning* of each
354 // cycle, before the pipeline simulation is performed.
356 // defined in eventq.cc
358 //////////////////////
359 extern EventQueue mainEventQueue;
361 #endif // __EVENTQ_HH__