sc_fifo.h

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

  The following code is derived, directly or indirectly, from the SystemC
  source code Copyright (c) 1996-2014 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 (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.accellera.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_fifo.h -- The sc_fifo<T> primitive channel class.

  Original Author: Martin Janssen, Synopsys, Inc., 2001-05-21

  CHANGE LOG IS AT THE END OF THE FILE
 *****************************************************************************/

#ifndef SC_FIFO_H
#define SC_FIFO_H


#include "sysc/communication/sc_communication_ids.h"
#include "sysc/communication/sc_prim_channel.h"
#include "sysc/communication/sc_fifo_ifs.h"
#include "sysc/kernel/sc_event.h"
#include "sysc/kernel/sc_simcontext.h"
#include "sysc/tracing/sc_trace.h"
#include <typeinfo>

namespace sc_core {

/**************************************************************************/
template <class T>
class sc_fifo
: public sc_fifo_in_if<T>,
  public sc_fifo_out_if<T>,
  public sc_prim_channel
{
public:

    // constructors

    explicit sc_fifo( int size_ = 16 )
        : sc_prim_channel( sc_gen_unique_name( "fifo" ) ),
          m_data_read_event(
              (std::string(SC_KERNEL_EVENT_PREFIX)+"_read_event").c_str()),
          m_data_written_event(
              (std::string(SC_KERNEL_EVENT_PREFIX)+"_write_event").c_str())
    { init( size_ ); }

    explicit sc_fifo( const char* name_, int size_ = 16 )
        : sc_prim_channel( name_ ),
          m_data_read_event(
              (std::string(SC_KERNEL_EVENT_PREFIX)+"_read_event").c_str()),
          m_data_written_event(
              (std::string(SC_KERNEL_EVENT_PREFIX)+"_write_event").c_str())
    { init( size_ ); }


    // destructor

    virtual ~sc_fifo()
    { delete [] m_buf; }


    // interface methods

    virtual void register_port( sc_port_base&, const char* );


    // blocking read

    // 08/19/2015 GL: modified for the OoO simulation
    virtual void read( T&, sc_segid );
    virtual void read( T&)
    {
      assert(false && "Should not be called");
    }

    // 08/19/2015 GL: modified for the OoO simulation
    virtual T read( sc_segid );
    virtual T read()
    {
      assert(false && "Should not be called");
    }

    // non-blocking read
    virtual bool nb_read( T& );


    // get the number of available samples

    virtual int num_available() const
    {
        // 02/24/2015 GL: acquire a lock to protect m_num_readable & m_num_read
        chnl_scoped_lock lock( m_mutex );

        return ( m_num_readable - m_num_read );
              // 02/24/2015 GL: return releases the lock
    }


    // get the data written event

    virtual const sc_event& data_written_event() const
    { return m_data_written_event; }


    // blocking write

    // 08/19/2015 GL: modified for the OoO simulation
    virtual void write( const T&, int );
    void write( const T& )
    {
      assert(false && "Should not be called");
    }

    // non-blocking write
    virtual bool nb_write( const T& );


    // get the number of free spaces

    virtual int num_free() const
    {
        // 02/24/2015 GL: acquire a lock to protect m_num_readable & 
        //                m_num_written
        chnl_scoped_lock lock( m_mutex );

        return ( m_size - m_num_readable - m_num_written );
        // 02/24/2015 GL: return releases the lock
    }


    // get the data read event

    virtual const sc_event& data_read_event() const
    { return m_data_read_event; }


    // other methods

    operator T ()
    { return read(); }


    // 08/24/2015 GL.
    sc_fifo<T>& operator = ( const T& a )
    { assert( 0 ); // 08/24/2015 GL: to support operator = in the future
      write( a, -5 ); return *this; }


    void trace( sc_trace_file* tf ) const;


    virtual void print( ::std::ostream& = ::std::cout ) const;
    virtual void dump( ::std::ostream& = ::std::cout ) const;

    virtual const char* kind() const
    { return "sc_fifo"; }

protected:

    virtual void update();

    // support methods

    void init( int );

    void buf_init( int );
    bool buf_write( const T& );
    bool buf_read( T& );

protected:

    int m_size;                 // size of the buffer
    T*  m_buf;                  // the buffer
    int m_free;                 // number of free spaces
    int m_ri;                   // index of next read
    int m_wi;                   // index of next write

    sc_port_base* m_reader;     // used for static design rule checking
    sc_port_base* m_writer;     // used for static design rule checking

    int m_num_readable;         // #samples readable
    int m_num_read;             // #samples read during this delta cycle
    int m_num_written;          // #samples written during this delta cycle

    sc_event m_data_read_event;
    sc_event m_data_written_event;

private:

    // disabled
    sc_fifo( const sc_fifo<T>& );
    sc_fifo& operator = ( const sc_fifo<T>& );
};


// IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

template <class T>
inline
void
sc_fifo<T>::register_port( sc_port_base& port_,
                            const char* if_typename_ )
{
    std::string nm( if_typename_ );
    if( nm == typeid( sc_fifo_in_if<T> ).name() ||
        nm == typeid( sc_fifo_blocking_in_if<T> ).name() 
    ) {
        // only one reader can be connected
        if( m_reader != 0 ) {
            SC_REPORT_ERROR( SC_ID_MORE_THAN_ONE_FIFO_READER_, 0 );
        }
        m_reader = &port_;
    } else if( nm == typeid( sc_fifo_out_if<T> ).name() ||
               nm == typeid( sc_fifo_blocking_out_if<T> ).name()
    ) {
        // only one writer can be connected
        if( m_writer != 0 ) {
            SC_REPORT_ERROR( SC_ID_MORE_THAN_ONE_FIFO_WRITER_, 0 );
        }
        m_writer = &port_;
    }
    else
    {
        SC_REPORT_ERROR( SC_ID_BIND_IF_TO_PORT_, 
                         "sc_fifo<T> port not recognized" );
    }
}


// blocking read

// 08/19/2015 GL: modified for the OoO simulation

template <class T>
inline
void
sc_fifo<T>::read( T& val_, sc_segid seg_id )
{
    // 02/24/2015 GL: acquire a lock to protect concurrent communication
    chnl_scoped_lock lock( m_mutex );

    while( num_available() == 0 ) {
        sc_core::wait( m_data_written_event, seg_id.seg_id );
    }
    m_num_read ++;
    buf_read( val_ );
    request_update();
    // 02/24/2015 GL: return releases the lock
}

// 02/24/2015 GL: protected by sc_fifo<T>::read(T&)
template <class T>
inline
T
sc_fifo<T>::read( sc_segid seg_id )
{
    T tmp;
    read( tmp, seg_id );
    return tmp;
}

// non-blocking read

template <class T>
inline
bool
sc_fifo<T>::nb_read( T& val_ )
{
    // 02/24/2015 GL: acquire a lock to protect concurrent communication
    chnl_scoped_lock lock( m_mutex );

    if( num_available() == 0 ) {
        return false;
    }
    m_num_read ++;
    buf_read( val_ );
    request_update();
    return true;
    // 02/24/2015 GL: return releases the lock
}


// blocking write

// 08/19/2015 GL: modified for the OoO simulation

template <class T>
inline
void
sc_fifo<T>::write( const T& val_, int seg_id )
{
    // 02/24/2015 GL: acquire a lock to protect concurrent communication
    chnl_scoped_lock lock( m_mutex );

    while( num_free() == 0 ) {
        sc_core::wait( m_data_read_event, seg_id );
    }
    m_num_written ++;
    buf_write( val_ );
    request_update();
    // 02/24/2015 GL: return releases the lock
}

// non-blocking write

template <class T>
inline
bool
sc_fifo<T>::nb_write( const T& val_ )
{
    // 02/24/2015 GL: acquire a lock to protect concurrent communication
    chnl_scoped_lock lock( m_mutex );

    if( num_free() == 0 ) {
        return false;
    }
    m_num_written ++;
    buf_write( val_ );
    request_update();
    return true;
    // 02/24/2015 GL: return releases the lock
}


// 02/24/2015 GL: take care of tracing in the future
template <class T>
inline
void
sc_fifo<T>::trace( sc_trace_file* tf ) const
{
#if defined(DEBUG_SYSTEMC)
    char buf[32];
    std::string nm = name();
    for( int i = 0; i < m_size; ++ i ) {
        std::sprintf( buf, "_%d", i );
        sc_trace( tf, m_buf[i], nm + buf );
    }
#endif
}


template <class T>
inline
void
sc_fifo<T>::print( ::std::ostream& os ) const
{
    // 02/24/2015 GL: acquire a lock to protect member variables
    chnl_scoped_lock lock( m_mutex );

    if( m_free != m_size ) {
        int i = m_ri;
        do {
            os << m_buf[i] << ::std::endl;
            i = ( i + 1 ) % m_size;
        } while( i != m_wi );
    }
    // 02/24/2015 GL: return releases the lock
}

template <class T>
inline
void
sc_fifo<T>::dump( ::std::ostream& os ) const
{
    // 02/24/2015 GL: acquire a lock to protect member variables
    chnl_scoped_lock lock( m_mutex );

    os << "name = " << name() << ::std::endl;
    if( m_free != m_size ) {
        int i = m_ri;
        int j = 0;
        do {
            os << "value[" << i << "] = " << m_buf[i] << ::std::endl;
            i = ( i + 1 ) % m_size;
            j ++;
        } while( i != m_wi );
    }
    // 02/24/2015 GL: return releases the lock
}


// 02/24/2015 GL: only executed in the update phase
template <class T>
inline
void
sc_fifo<T>::update()
{
    if( m_num_read > 0 ) {
        m_data_read_event.notify(SC_ZERO_TIME);
    }

    if( m_num_written > 0 ) {
        m_data_written_event.notify(SC_ZERO_TIME);
    }

    m_num_readable = m_size - m_free;
    m_num_read = 0;
    m_num_written = 0;
}


// support methods

// 02/24/2015 GL: already protected in public methods
template <class T>
inline
void
sc_fifo<T>::init( int size_ )
{
    buf_init( size_ );

    m_reader = 0;
    m_writer = 0;

    m_num_readable = 0;
    m_num_read = 0;
    m_num_written = 0;
}


// 02/24/2015 GL: already protected in public methods
template <class T>
inline
void
sc_fifo<T>::buf_init( int size_ )
{
    if( size_ <= 0 ) {
        SC_REPORT_ERROR( SC_ID_INVALID_FIFO_SIZE_, 0 );
    }
    m_size = size_;
    m_buf = new T[m_size];
    m_free = m_size;
    m_ri = 0;
    m_wi = 0;
}

// 02/24/2015 GL: already protected in public methods
template <class T>
inline
bool
sc_fifo<T>::buf_write( const T& val_ )
{
    if( m_free == 0 ) {
        return false;
    }
    m_buf[m_wi] = val_;
    m_wi = ( m_wi + 1 ) % m_size;
    m_free --;
    return true;
}

// 02/24/2015 GL: already protected in public methods
template <class T>
inline
bool
sc_fifo<T>::buf_read( T& val_ )
{
    if( m_free == m_size ) {
        return false;
    }
    val_ = m_buf[m_ri];
    m_buf[m_ri] = T(); // clear entry for boost::shared_ptr, et al.
    m_ri = ( m_ri + 1 ) % m_size;
    m_free ++;
    return true;
}


// ----------------------------------------------------------------------------

template <class T>
inline
::std::ostream&
operator << ( ::std::ostream& os, const sc_fifo<T>& a )
{
    a.print( os );
    return os;
}

} // namespace sc_core

//$Log: sc_fifo.h,v $
//Revision 1.6  2011/08/26 20:45:40  acg
// Andy Goodrich: moved the modification log to the end of the file to
// eliminate source line number skew when check-ins are done.
//
//Revision 1.5  2011/03/23 16:17:22  acg
// Andy Goodrich: hide the sc_events that are kernel related.
//
//Revision 1.4  2011/02/18 20:23:45  acg
// Andy Goodrich: Copyright update.
//
//Revision 1.3  2009/10/14 19:05:40  acg
// Andy Goodrich: added check for blocking interfaces in addition to the
// combined blocking/nonblocking interface.
//
//Revision 1.2  2009/05/22 16:06:24  acg
// Andy Goodrich: process control updates.
//
//Revision 1.1.1.1  2006/12/15 20:20:04  acg
//SystemC 2.3
//
//Revision 1.4  2006/01/24 20:46:31  acg
//Andy Goodrich: changes to eliminate use of deprecated features. For instance,
//using notify(SC_ZERO_TIME) in place of notify_delayed().
//
//Revision 1.3  2006/01/13 20:41:59  acg
//Andy Goodrich: Changes to add port registration to the things that are
//checked when SC_NO_WRITE_CHECK is not defined.
//
//Revision 1.2  2006/01/03 23:18:26  acg
//Changed copyright to include 2006.
//
//Revision 1.1.1.1  2005/12/19 23:16:43  acg
//First check in of SystemC 2.1 into its own archive.
//
//Revision 1.12  2005/09/15 23:01:51  acg
//Added std:: prefix to appropriate methods and types to get around
//issues with the Edison Front End.
//
//Revision 1.11  2005/06/10 22:43:55  acg
//Added CVS change log annotation.
//

#endif

// Taf!