ext/systemc/src/sysc/communication/sc_mutex.cpp

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

  sc_mutex.cpp -- The sc_mutex primitive channel class.

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

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

#include "sysc/communication/sc_mutex.h"
#include "sysc/kernel/sc_simcontext.h"

namespace sc_core {

// ----------------------------------------------------------------------------
//  CLASS : sc_mutex
//
//  The sc_mutex primitive channel class.
// ----------------------------------------------------------------------------

// constructors

sc_mutex::sc_mutex()
: sc_object( sc_gen_unique_name( "mutex" ) ),
  m_owner( 0 ),
  m_free( (std::string(SC_KERNEL_EVENT_PREFIX)+"_free_event").c_str() )
{}

sc_mutex::sc_mutex( const char* name_ )
: sc_object( name_ ),
  m_owner( 0 ),
  m_free( (std::string(SC_KERNEL_EVENT_PREFIX)+"_free_event").c_str() )
{}


// destructor

sc_mutex::~sc_mutex()
{}

// interface methods

// blocks until mutex could be locked

int
sc_mutex::lock()
{
    if ( m_owner == sc_get_current_process_b()) return 0;
    while( in_use() ) {
	sc_core::wait( m_free, sc_get_curr_simcontext() );
    }
    m_owner = sc_get_current_process_b();
    return 0;
}


// returns -1 if mutex could not be locked

int
sc_mutex::trylock()
{
    if ( m_owner == sc_get_current_process_b()) return 0;
    if( in_use() ) {
	return -1;
    }
    m_owner = sc_get_current_process_b();
    return 0;
}


// returns -1 if mutex was not locked by caller

int
sc_mutex::unlock()
{
    if( m_owner != sc_get_current_process_b() ) {
	return -1;
    }
    m_owner = 0;
    m_free.notify();
    return 0;
}

} // namespace sc_core

// $Log: sc_mutex.cpp,v $
// Revision 1.7  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 1.6  2011/03/28 13:02:29  acg
//  Andy Goodrich: removed sc_event in sc_mutex class from the object
//  hierarchy since it is considered a "kernel" event.
//
// Revision 1.5  2011/02/18 20:23:45  acg
//  Andy Goodrich: Copyright update.
//
// Revision 1.4  2010/11/02 16:31:01  acg
//  Andy Goodrich: changed object derivation to use sc_object rather than
//  sc_prim_channel as the parent class.
//
// Revision 1.3  2008/11/13 15:29:46  acg
//  David C. Black, ESLX, Inc: lock & trylock now allow owner to apply
//  lock more than once without incident. Previous behavior locked up the
//  owning process.
//
// Revision 1.2  2008/05/20 16:46:18  acg
//  Andy Goodrich: added checks for multiple writers.
//
// Revision 1.1.1.1  2006/12/15 20:20:04  acg
// SystemC 2.3
//
// Revision 1.4  2006/03/21 00:00:27  acg
//   Andy Goodrich: changed name of sc_get_current_process_base() to be
//   sc_get_current_process_b() since its returning an sc_process_b instance.
//
// Revision 1.3  2006/01/13 18:47:42  acg
// Added $Log command so that CVS comments are reproduced in the source.
//

// Taf!