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

  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_signal_resolved.cpp -- The resolved signal class.

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

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

#include "sysc/kernel/sc_simcontext.h"
#include "sysc/kernel/sc_process_handle.h"
#include "sysc/communication/sc_signal_resolved.h"

namespace sc_core {

// Note that we assume that two drivers driving the resolved signal to a 1 or
// 0 is O.K. This might not be true for all technologies, but is certainly
// true for CMOS, the predominant technology in use today.

const sc_dt::sc_logic_value_t
sc_logic_resolution_tbl[4][4] =
{   //    0      1      Z      X
    { sc_dt::Log_0, sc_dt::Log_X, sc_dt::Log_0, sc_dt::Log_X }, // 0
    { sc_dt::Log_X, sc_dt::Log_1, sc_dt::Log_1, sc_dt::Log_X }, // 1
    { sc_dt::Log_0, sc_dt::Log_1, sc_dt::Log_Z, sc_dt::Log_X }, // Z
    { sc_dt::Log_X, sc_dt::Log_X, sc_dt::Log_X, sc_dt::Log_X }  // X
};


// ----------------------------------------------------------------------------
//  FUNCTION : sc_logic_resolve
//
//  Resolution function for sc_dt::sc_logic.
// ----------------------------------------------------------------------------

// resolves sc_dt::sc_logic values and returns the resolved value

static void
sc_logic_resolve( sc_dt::sc_logic& result_,
                  const std::vector<sc_dt::sc_logic>& values_ )
{
    int sz = values_.size();

    assert( sz != 0 );

    if( sz == 1 ) {
	result_ = values_[0];
	return;
    }

    sc_dt::sc_logic_value_t res = values_[0].value();
    for( int i = sz - 1; i > 0 && res != sc_dt::Log_X; -- i ) {
       res = sc_logic_resolution_tbl[res][values_[i].value()];
    }
    result_ = res;
}


// ----------------------------------------------------------------------------
//  CLASS : sc_signal_resolved
//
//  The resolved signal class.
// ----------------------------------------------------------------------------

// write the new value

void
sc_signal_resolved::write( const data_type& value_ )
{
    sc_process_b* cur_proc = sc_get_current_process_b();

    bool value_changed = false;
    bool found = false;
    
    for( int i = m_proc_vec.size() - 1; i >= 0; -- i ) {
	if( cur_proc == m_proc_vec[i] ) {
	    if( value_ != m_val_vec[i] ) {
		m_val_vec[i] = value_;
		value_changed = true;
	    }
	    found = true;
	    break;
	}
    }
    
    if( ! found ) {
	m_proc_vec.push_back( cur_proc );
	m_val_vec.push_back( value_ );
	value_changed = true;
    }
    
    if( value_changed ) {
	request_update();
    }
}


void
sc_signal_resolved::update()
{
    sc_logic_resolve( m_new_val, m_val_vec );
    base_type::update();
}


} // namespace sc_core

// $Log: sc_signal_resolved.cpp,v $
// Revision 1.5  2011/08/26 20:45:44  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  2011/02/18 20:23:45  acg
//  Andy Goodrich: Copyright update.
//
// Revision 1.3  2011/02/07 19:16:50  acg
//  Andy Goodrich: changes for handling multiple writers.
//
// Revision 1.2  2011/01/20 16:52:15  acg
//  Andy Goodrich: changes for IEEE 1666 2011.
//
// 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!
