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sc_event_queue.h

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/*****************************************************************************

  The following code is derived, directly or indirectly, from the SystemC
  source code Copyright (c) 1996-2004 by all Contributors.
  All Rights reserved.

  The contents of this file are subject to the restrictions and limitations
  set forth in the SystemC Open Source License Version 2.3 (the "License");
  You may not use this file except in compliance with such restrictions and
  limitations. You may obtain instructions on how to receive a copy of the
  License at http://www.systemc.org/. Software distributed by Contributors
  under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF
  ANY KIND, either express or implied. See the License for the specific
  language governing rights and limitations under the License.

 *****************************************************************************/

/*****************************************************************************

  sc_event_queue.h -- Event Queue Facility Definitions

  Original Author: Stuart Swan, Cadence Inc.

 *****************************************************************************/

/*****************************************************************************

  MODIFICATION LOG - modifiers, enter your name, affiliation, date and
  changes you are making here.

      Name, Affiliation, Date:
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#ifndef SC_EVENT_QUEUE_H
#define SC_EVENT_QUEUE_H


/*
  Class sc_event_queue

  A queue that can contain any number of pending notifications.
  The queue has a similiar interface like an sc_event but has different
  semantics: it can carry any number of pending notification. The
  general rule is that _every_ call to notify() will cause a 
  corresponding trigger at the specified wall-clock time that can be
  observed (the only exception is when notifications are explicitly
  cancelled). 

  If multiple notifications are pending at the same wall-clock
  time, then the event queue will trigger in different delta cycles
  in order to ensure that sensitive processes can notice each
  trigger. The first trigger happens in the earliest delta cycle
  possible which is the same behavior as a normal timed event.
  
*/

#include "systemc/communication/sc_interface.h"
#include "systemc/kernel/sc_module.h"

template <class IF, int N>
class sc_port;


// ---------------------------------------------------------------------------
// sc_event_queue_if
// ---------------------------------------------------------------------------

class sc_event_queue_if : public virtual sc_interface
{
public:
    virtual void notify (double when, sc_time_unit base) =0;
    virtual void notify (const sc_time& when) =0;
    virtual void cancel_all() =0;
};

// ---------------------------------------------------------------------------
// sc_event_queue: a queue that can contain any number of pending 
// delta, or timed events.
// ---------------------------------------------------------------------------

class sc_event_queue: 
  public sc_event_queue_if,
  public sc_module
{
 public:

    SC_HAS_PROCESS( sc_event_queue );

    sc_event_queue();
    sc_event_queue( sc_module_name name_ );
    ~sc_event_queue();


    //
    // API of sc_event_queue_if
    //
    inline virtual void notify (double when, sc_time_unit base);
           virtual void notify (const sc_time& when);
           virtual void cancel_all();

    //
    // API for using the event queue in processes
    //

    // get the default event
    inline virtual const sc_event& default_event() const;

/*
    //
    // Possible extensions:
    //
    
    // Cancel an events at a specific time
    void cancel (const sc_time& when);
    void cancel (double when, sc_time_unit base);

    // How many events are pending altogether?
    unsigned pending() const;

    // How many events are pending at the specific time?
    unsigned pending(const sc_time& when) const;
    unsigned pending(double when, sc_time_unit base) const;
*/

 private:
    void fire_event();

 private:
    sc_ppq<sc_time*> m_ppq;
    sc_event m_e;
    uint64 m_delta;
    unsigned m_pending_delta;
};

inline
void sc_event_queue::notify (double when, sc_time_unit base )
{
  notify( sc_time(when,base) );
}
    
inline
const sc_event& sc_event_queue::default_event() const
{ 
  return m_e; 
}


//
// Using event queue as a port
//
typedef sc_port<sc_event_queue_if,1> sc_event_queue_port;


#endif // SC_EVENT_QUEUE_H

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