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+/*
+ * Copyright (c) 2000-2005 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Steve Reinhardt
+ * Nathan Binkert
+ */
+
+/* @file
+ * EventQueue interfaces
+ */
+
+#ifndef __SIM_EVENTQ_HH__
+#define __SIM_EVENTQ_HH__
+
+#include <assert.h>
+
+#include <algorithm>
+#include <map>
+#include <string>
+#include <vector>
+
+#include "sim/host.hh" // for Tick
+
+#include "base/fast_alloc.hh"
+#include "base/trace.hh"
+#include "sim/serialize.hh"
+
+class EventQueue; // forward declaration
+
+//////////////////////
+//
+// Main Event Queue
+//
+// Events on this queue are processed at the *beginning* of each
+// cycle, before the pipeline simulation is performed.
+//
+// defined in eventq.cc
+//
+//////////////////////
+extern EventQueue mainEventQueue;
+
+
+/*
+ * An item on an event queue. The action caused by a given
+ * event is specified by deriving a subclass and overriding the
+ * process() member function.
+ */
+class Event : public Serializable, public FastAlloc
+{
+ friend class EventQueue;
+
+ private:
+ /// queue to which this event belongs (though it may or may not be
+ /// scheduled on this queue yet)
+ EventQueue *queue;
+
+ Event *next;
+
+ Tick _when; //!< timestamp when event should be processed
+ int _priority; //!< event priority
+ char _flags;
+
+ protected:
+ enum Flags {
+ None = 0x0,
+ Squashed = 0x1,
+ Scheduled = 0x2,
+ AutoDelete = 0x4,
+ AutoSerialize = 0x8,
+ IsExitEvent = 0x10
+ };
+
+ bool getFlags(Flags f) const { return (_flags & f) == f; }
+ void setFlags(Flags f) { _flags |= f; }
+ void clearFlags(Flags f) { _flags &= ~f; }
+
+ protected:
+ EventQueue *theQueue() const { return queue; }
+
+#if TRACING_ON
+ Tick when_created; //!< Keep track of creation time For debugging
+ Tick when_scheduled; //!< Keep track of creation time For debugging
+
+ virtual void trace(const char *action); //!< trace event activity
+#else
+ void trace(const char *) {}
+#endif
+
+ unsigned annotated_value;
+
+ public:
+
+ /// Event priorities, to provide tie-breakers for events scheduled
+ /// at the same cycle. Most events are scheduled at the default
+ /// priority; these values are used to control events that need to
+ /// be ordered within a cycle.
+ enum Priority {
+ /// Breakpoints should happen before anything else, so we
+ /// don't miss any action when debugging.
+ Debug_Break_Pri = -100,
+
+ /// For some reason "delayed" inter-cluster writebacks are
+ /// scheduled before regular writebacks (which have default
+ /// priority). Steve?
+ Delayed_Writeback_Pri = -1,
+
+ /// Default is zero for historical reasons.
+ Default_Pri = 0,
+
+ /// CPU switches schedule the new CPU's tick event for the
+ /// same cycle (after unscheduling the old CPU's tick event).
+ /// The switch needs to come before any tick events to make
+ /// sure we don't tick both CPUs in the same cycle.
+ CPU_Switch_Pri = 31,
+
+ /// Serailization needs to occur before tick events also, so
+ /// that a serialize/unserialize is identical to an on-line
+ /// CPU switch.
+ Serialize_Pri = 32,
+
+ /// CPU ticks must come after other associated CPU events
+ /// (such as writebacks).
+ CPU_Tick_Pri = 50,
+
+ /// Statistics events (dump, reset, etc.) come after
+ /// everything else, but before exit.
+ Stat_Event_Pri = 90,
+
+ /// If we want to exit on this cycle, it's the very last thing
+ /// we do.
+ Sim_Exit_Pri = 100
+ };
+
+ /*
+ * Event constructor
+ * @param queue that the event gets scheduled on
+ */
+ Event(EventQueue *q, Priority p = Default_Pri)
+ : queue(q), next(NULL), _priority(p), _flags(None),
+#if TRACING_ON
+ when_created(curTick), when_scheduled(0),
+#endif
+ annotated_value(0)
+ {
+ }
+
+ ~Event() {}
+
+ virtual const std::string name() const {
+ return csprintf("Event_%x", (uintptr_t)this);
+ }
+
+ /// Determine if the current event is scheduled
+ bool scheduled() const { return getFlags(Scheduled); }
+
+ /// Schedule the event with the current priority or default priority
+ void schedule(Tick t);
+
+ /// Reschedule the event with the current priority
+ void reschedule(Tick t);
+
+ /// Remove the event from the current schedule
+ void deschedule();
+
+ /// Return a C string describing the event. This string should
+ /// *not* be dynamically allocated; just a const char array
+ /// describing the event class.
+ virtual const char *description();
+
+ /// Dump the current event data
+ void dump();
+
+ /*
+ * This member function is invoked when the event is processed
+ * (occurs). There is no default implementation; each subclass
+ * must provide its own implementation. The event is not
+ * automatically deleted after it is processed (to allow for
+ * statically allocated event objects).
+ *
+ * If the AutoDestroy flag is set, the object is deleted once it
+ * is processed.
+ */
+ virtual void process() = 0;
+
+ void annotate(unsigned value) { annotated_value = value; };
+ unsigned annotation() { return annotated_value; }
+
+ /// Squash the current event
+ void squash() { setFlags(Squashed); }
+
+ /// Check whether the event is squashed
+ bool squashed() { return getFlags(Squashed); }
+
+ /// See if this is a SimExitEvent (without resorting to RTTI)
+ bool isExitEvent() { return getFlags(IsExitEvent); }
+
+ /// Get the time that the event is scheduled
+ Tick when() const { return _when; }
+
+ /// Get the event priority
+ int priority() const { return _priority; }
+
+ struct priority_compare :
+ public std::binary_function<Event *, Event *, bool>
+ {
+ bool operator()(const Event *l, const Event *r) const {
+ return l->when() >= r->when() || l->priority() >= r->priority();
+ }
+ };
+
+ virtual void serialize(std::ostream &os);
+ virtual void unserialize(Checkpoint *cp, const std::string &section);
+};
+
+template <class T, void (T::* F)()>
+void
+DelayFunction(Tick when, T *object)
+{
+ class DelayEvent : public Event
+ {
+ private:
+ T *object;
+
+ public:
+ DelayEvent(Tick when, T *o)
+ : Event(&mainEventQueue), object(o)
+ { setFlags(this->AutoDestroy); schedule(when); }
+ void process() { (object->*F)(); }
+ const char *description() { return "delay"; }
+ };
+
+ new DelayEvent(when, object);
+}
+
+template <class T, void (T::* F)()>
+class EventWrapper : public Event
+{
+ private:
+ T *object;
+
+ public:
+ EventWrapper(T *obj, bool del = false, EventQueue *q = &mainEventQueue,
+ Priority p = Default_Pri)
+ : Event(q, p), object(obj)
+ {
+ if (del)
+ setFlags(AutoDelete);
+ }
+ void process() { (object->*F)(); }
+};
+
+/*
+ * Queue of events sorted in time order
+ */
+class EventQueue : public Serializable
+{
+ protected:
+ std::string objName;
+
+ private:
+ Event *head;
+
+ void insert(Event *event);
+ void remove(Event *event);
+
+ public:
+
+ // constructor
+ EventQueue(const std::string &n)
+ : objName(n), head(NULL)
+ {}
+
+ virtual const std::string name() const { return objName; }
+
+ // schedule the given event on this queue
+ void schedule(Event *ev);
+ void deschedule(Event *ev);
+ void reschedule(Event *ev);
+
+ Tick nextTick() { return head->when(); }
+ Event *serviceOne();
+
+ // process all events up to the given timestamp. we inline a
+ // quick test to see if there are any events to process; if so,
+ // call the internal out-of-line version to process them all.
+ void serviceEvents(Tick when) {
+ while (!empty()) {
+ if (nextTick() > when)
+ break;
+
+ /**
+ * @todo this assert is a good bug catcher. I need to
+ * make it true again.
+ */
+ //assert(head->when() >= when && "event scheduled in the past");
+ serviceOne();
+ }
+ }
+
+ // default: process all events up to 'now' (curTick)
+ void serviceEvents() { serviceEvents(curTick); }
+
+ // return true if no events are queued
+ bool empty() { return head == NULL; }
+
+ void dump();
+
+ Tick nextEventTime() { return empty() ? curTick : head->when(); }
+
+ virtual void serialize(std::ostream &os);
+ virtual void unserialize(Checkpoint *cp, const std::string &section);
+};
+
+
+//////////////////////
+//
+// inline functions
+//
+// can't put these inside declaration due to circular dependence
+// between Event and EventQueue classes.
+//
+//////////////////////
+
+// schedule at specified time (place on event queue specified via
+// constructor)
+inline void
+Event::schedule(Tick t)
+{
+ assert(!scheduled());
+ assert(t >= curTick);
+
+ setFlags(Scheduled);
+#if TRACING_ON
+ when_scheduled = curTick;
+#endif
+ _when = t;
+ queue->schedule(this);
+}
+
+inline void
+Event::deschedule()
+{
+ assert(scheduled());
+
+ clearFlags(Squashed);
+ clearFlags(Scheduled);
+ queue->deschedule(this);
+}
+
+inline void
+Event::reschedule(Tick t)
+{
+ assert(scheduled());
+ clearFlags(Squashed);
+
+#if TRACING_ON
+ when_scheduled = curTick;
+#endif
+ _when = t;
+ queue->reschedule(this);
+}
+
+inline void
+EventQueue::schedule(Event *event)
+{
+ insert(event);
+ if (DTRACE(Event))
+ event->trace("scheduled");
+}
+
+inline void
+EventQueue::deschedule(Event *event)
+{
+ remove(event);
+ if (DTRACE(Event))
+ event->trace("descheduled");
+}
+
+inline void
+EventQueue::reschedule(Event *event)
+{
+ remove(event);
+ insert(event);
+ if (DTRACE(Event))
+ event->trace("rescheduled");
+}
+
+
+
+#endif // __SIM_EVENTQ_HH__
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