xref: /gem5/ext/systemc/src/sysc/communication/sc_semaphore.cpp

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  implied.  See the License for the specific language governing
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/*****************************************************************************

  sc_semaphore.cpp -- The sc_semaphore 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_communication_ids.h"
#include "sysc/communication/sc_semaphore.h"
#include "sysc/kernel/sc_simcontext.h"
#include "sysc/kernel/sc_wait.h"

namespace sc_core {

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

// error reporting

void
sc_semaphore::report_error( const char* id, const char* add_msg ) const
{
    char msg[BUFSIZ];
    if( add_msg != 0 ) {
	std::sprintf( msg, "%s: semaphore '%s'", add_msg, name() );
    } else {
	std::sprintf( msg, "semaphore '%s'", name() );
    }
    SC_REPORT_ERROR( id, msg );
}


// constructors

sc_semaphore::sc_semaphore( int init_value_ )
: sc_object( sc_gen_unique_name( "semaphore" ) ),
  m_free( (std::string(SC_KERNEL_EVENT_PREFIX)+"_free_event").c_str() ),
  m_value( init_value_ )
{
    if( m_value < 0 ) {
	report_error( SC_ID_INVALID_SEMAPHORE_VALUE_ );
    }
}

sc_semaphore::sc_semaphore( const char* name_, int init_value_ )
: sc_object( name_ ),
  m_free( (std::string(SC_KERNEL_EVENT_PREFIX)+"_free_event").c_str() ),
  m_value( init_value_ )
{
    if( m_value < 0 ) {
	report_error( SC_ID_INVALID_SEMAPHORE_VALUE_ );
    }
}


// interface methods

// lock (take) the semaphore, block if not available

int
sc_semaphore::wait()
{
    while( in_use() ) {
	sc_core::wait( m_free, sc_get_curr_simcontext() );
    }
    -- m_value;
    return 0;
}


// lock (take) the semaphore, return -1 if not available

int
sc_semaphore::trywait()
{
    if( in_use() ) {
	return -1;
    }
    -- m_value;
    return 0;
}


// unlock (give) the semaphore

int
sc_semaphore::post()
{
    ++m_value;
    m_free.notify();
    return 0;
}

} // namespace sc_core

// $Log: sc_semaphore.cpp,v $
// Revision 1.5  2011/08/26 20:45:42  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 1.4  2011/03/23 16:17:22  acg
//  Andy Goodrich: hide the sc_events that are kernel related.
//
// Revision 1.3  2011/02/18 20:23:45  acg
//  Andy Goodrich: Copyright update.
//
// Revision 1.2  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 1.1.1.1  2006/12/15 20:20:04  acg
// SystemC 2.3
//
// Revision 1.6  2006/11/28 20:30:49  acg
//  Andy Goodrich: updated from 2.2 source. sc_event_queue constructors
//  collapsed into a single constructor with an optional argument to get
//  the sc_module_name stack done correctly. Class name prefixing added
//  to sc_semaphore calls to wait() to keep gcc 4.x happy.
//
// Revision 1.3  2006/01/13 18:47:42  acg
// Added $Log command so that CVS comments are reproduced in the source.
//

// Taf!