ext/systemc/src/sysc/kernel/sc_reset.cpp

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  with this work for additional information regarding copyright ownership.
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/*****************************************************************************

  sc_reset.cpp -- Support for reset.

  Original Author: Andy Goodrich, Forte Design Systems

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


#include "sysc/kernel/sc_simcontext.h"
#include "sysc/kernel/sc_reset.h"
#include "sysc/kernel/sc_process_handle.h"
#include "sysc/communication/sc_signal.h"
#include "sysc/communication/sc_signal_ports.h"


// THE SYSTEMC PROOF OF CONCEPT SIMULATOR RESET SIGNAL IMPLEMENTATION:
//
// (1) An instance of the sc_reset class is attached to each sc_signal<bool> 
//     that is used as a reset signal.
//
// (2) Each process that is senstive to a reset signal will be registered in the
//     sc_reset class attached to that reset signal.
//
// (3) When a change in the value of a reset signal occurs it invokes the
//     notify_processes() method of its sc_reset object instance. The 
//     notify_processes() method will call the reset_changed() method of each
//     process that is registered with it to inform the process that 
//     state of the reset signal has changed.
//
// (4) A process may have multiple reset signals, so counters are kept for the 
//     number of active asynchronous, and synchronous, reset signals that are
//     active. Those counters are incremented and decremented in the process'
//     reset_changed() method.
//
// (5) When a process' semantics() method is called the current reset state is
//     checked, and a reset sequence is initiated if the process is in reset.
//     This will occur every time an SC_METHOD is dispatched. SC_CTHREAD and
//     and SC_THREAD instances, only go through the semantics() method they
//     initially start up. So the reset check  is duplicated in the suspend_me()
//     method, the tail of which will execute each time the thread is 
//     dispatched.

namespace sc_core {

class sc_reset_finder;
static sc_reset_finder* reset_finder_q=0;  // Q of reset finders to reconcile.

//==============================================================================
// sc_reset_finder - place holder class for a port reset signal until it is
//                   bound and an interface class is available. When the port
//                   has been bound the information in this class will be used
//                   to initialize its sc_reset object instance.
//==============================================================================
class sc_reset_finder {
    friend class sc_reset;
  public:
    sc_reset_finder( bool async, const sc_in<bool>* port_p, bool level, 
        sc_process_b* target_p);
    sc_reset_finder( bool async, const sc_inout<bool>* port_p, bool level, 
        sc_process_b* target_p);
    sc_reset_finder( bool async, const sc_out<bool>* port_p, bool level, 
        sc_process_b* target_p);

  protected:
    bool                   m_async;     // True if asynchronous reset.
    bool                   m_level;     // Level for reset.
    sc_reset_finder*       m_next_p;    // Next reset finder in list.
    const sc_in<bool>*     m_in_p;      // Port for which reset is needed.
    const sc_inout<bool>*  m_inout_p;   // Port for which reset is needed.
    const sc_out<bool>*    m_out_p;     // Port for which reset is needed.
    sc_process_b*          m_target_p;  // Process to reset.

  private: // disabled
    sc_reset_finder( const sc_reset_finder& );
    const sc_reset_finder& operator = ( const sc_reset_finder& );
};

inline sc_reset_finder::sc_reset_finder(
    bool async, const sc_in<bool>* port_p, bool level, sc_process_b* target_p) :
    m_async(async), m_level(level), m_next_p(0), m_in_p(port_p), m_inout_p(0), 
    m_out_p(0), m_target_p(target_p)
{   
    m_next_p = reset_finder_q;
    reset_finder_q = this;
}

inline sc_reset_finder::sc_reset_finder(
    bool async, const sc_inout<bool>* port_p, bool level, sc_process_b* target_p
) : 
    m_async(async), m_level(level), m_next_p(0), m_in_p(0), m_inout_p(port_p), 
    m_out_p(0), m_target_p(target_p)
{   
    m_next_p = reset_finder_q;
    reset_finder_q = this;
}

inline sc_reset_finder::sc_reset_finder(
    bool async, const sc_out<bool>* port_p, bool level, sc_process_b* target_p
) : 
    m_async(async), m_level(level), m_next_p(0), m_in_p(0), m_inout_p(0),
    m_out_p(port_p), m_target_p(target_p)
{   
    m_next_p = reset_finder_q;
    reset_finder_q = this;
}


//------------------------------------------------------------------------------
//"sc_reset::notify_processes"
//
// Notify processes that there is a change in the reset signal value.
//------------------------------------------------------------------------------
void sc_reset::notify_processes()
{
    bool                                    active;       // true if reset is active.
    sc_reset_target*                        entry_p;      // reset entry processing.
    std::vector<sc_reset_target>::size_type process_i;    // index of process resetting.
    std::vector<sc_reset_target>::size_type process_n;    // # of processes to reset.
    bool                                    value;        // value of our signal.

    value = m_iface_p->read();
    process_n = m_targets.size();
    for ( process_i = 0; process_i < process_n; process_i++ )
    {
        entry_p = &m_targets[process_i];
	active = ( entry_p->m_level == value );
	entry_p->m_process_p->reset_changed( entry_p->m_async, active );
    }
}


//------------------------------------------------------------------------------
//"sc_reset::reconcile_resets"
//
// This static method processes the sc_reset_finders to establish the actual
// reset connections.
//
// Notes:
//   (1) If reset is asserted we tell the process that it is in reset.
//------------------------------------------------------------------------------
void sc_reset::reconcile_resets()
{
    const sc_signal_in_if<bool>*  iface_p;      // Interface to reset signal.
    sc_reset_finder*              next_p;       // Next finder to process.
    sc_reset_finder*              now_p;        // Finder currently processing.
    sc_reset_target               reset_target; // Target's reset entry.
    sc_reset*                     reset_p;      // Reset object to use.

    for ( now_p = reset_finder_q; now_p; now_p = next_p )
    {
        next_p = now_p->m_next_p;
        if ( now_p->m_in_p )
        {
            iface_p = DCAST<const sc_signal_in_if<bool>*>(
                now_p->m_in_p->get_interface());
        }
        else if ( now_p->m_inout_p )
        {
            iface_p = DCAST<const sc_signal_in_if<bool>*>(
                now_p->m_inout_p->get_interface());
        }
        else
        {
            iface_p = DCAST<const sc_signal_in_if<bool>*>(
                now_p->m_out_p->get_interface());
        }
        assert( iface_p != 0 );
        reset_p = iface_p->is_reset();
	now_p->m_target_p->m_resets.push_back(reset_p);
	reset_target.m_async = now_p->m_async;
	reset_target.m_level = now_p->m_level;
	reset_target.m_process_p = now_p->m_target_p;
	reset_p->m_targets.push_back(reset_target);
	if ( iface_p->read() == now_p->m_level ) // see note 1 above
	    now_p->m_target_p->initially_in_reset( now_p->m_async );
        delete now_p;
    }
}


//------------------------------------------------------------------------------
//"sc_reset::remove_process"
//
// This method removes the supplied process from the list of processes that
// should be notified when there is a change in the value of the reset signal.
//
// Arguments:
//     process_p -> process to be removed.
//------------------------------------------------------------------------------
void sc_reset::remove_process( sc_process_b* process_p )
{
    int process_i; // Index of process resetting.
    int process_n; // # of processes to reset.

    process_n = m_targets.size();
    for ( process_i = 0; process_i < process_n; )
    {
        if ( m_targets[process_i].m_process_p == process_p )
        {
            m_targets[process_i] = m_targets[process_n-1];
	    process_n--;
            m_targets.resize(process_n);
        }
	else
	{
	    process_i++;
	}
    }
}

//------------------------------------------------------------------------------
//"sc_reset::reset_signal_is - ports"
//
// These overloads of the reset_signal_is() method will register the active
// process with the sc_reset object instance associated with the supplied port.
// If the port does not yet have a pointer to its sc_signal<bool> instance it
// will create an sc_reset_finder class object instance that will be used
// to set the process' reset information when the port has been bound.
//
// Arguments:
//     async = true if the reset signal is asynchronous, false if not.
//     port  = port for sc_signal<bool> that will provide the reset signal.
//     level = level at which reset is active, either true or false.
//------------------------------------------------------------------------------
void sc_reset::reset_signal_is( bool async, const sc_in<bool>& port, bool level)
{
    const sc_signal_in_if<bool>* iface_p;
    sc_process_b*                process_p;
    
    process_p = (sc_process_b*)sc_get_current_process_handle();
    assert( process_p );
    process_p->m_has_reset_signal = true;
    switch ( process_p->proc_kind() )
    {
      case SC_THREAD_PROC_:
      case SC_METHOD_PROC_:
      case SC_CTHREAD_PROC_:
        iface_p = DCAST<const sc_signal_in_if<bool>*>(port.get_interface());
        if ( iface_p )
            reset_signal_is( async, *iface_p, level );
        else
            new sc_reset_finder( async, &port, level, process_p );
        break;
      default:
        SC_REPORT_ERROR(SC_ID_UNKNOWN_PROCESS_TYPE_, process_p->name());
        break;
    }
}

void sc_reset::reset_signal_is(
    bool async, const sc_inout<bool>& port, bool level )
{
    const sc_signal_in_if<bool>* iface_p;
    sc_process_b*                process_p;
    
    process_p = (sc_process_b*)sc_get_current_process_handle();
    assert( process_p );
    process_p->m_has_reset_signal = true;
    switch ( process_p->proc_kind() )
    {
      case SC_THREAD_PROC_:
      case SC_METHOD_PROC_:
      case SC_CTHREAD_PROC_:
        iface_p = DCAST<const sc_signal_in_if<bool>*>(port.get_interface());
        if ( iface_p )
            reset_signal_is( async, *iface_p, level );
        else
            new sc_reset_finder( async, &port, level, process_p );
        break;
      default:
        SC_REPORT_ERROR(SC_ID_UNKNOWN_PROCESS_TYPE_, process_p->name());
        break;
    }
}

void sc_reset::reset_signal_is(
    bool async, const sc_out<bool>& port, bool level )
{
    const sc_signal_in_if<bool>* iface_p;
    sc_process_b*                process_p;
    
    process_p = (sc_process_b*)sc_get_current_process_handle();
    assert( process_p );
    process_p->m_has_reset_signal = true;
    switch ( process_p->proc_kind() )
    {
      case SC_THREAD_PROC_:
      case SC_METHOD_PROC_:
      case SC_CTHREAD_PROC_:
        iface_p = DCAST<const sc_signal_in_if<bool>*>(port.get_interface());
        if ( iface_p )
            reset_signal_is( async, *iface_p, level );
        else
            new sc_reset_finder( async, &port, level, process_p );
        break;
      default:
        SC_REPORT_ERROR(SC_ID_UNKNOWN_PROCESS_TYPE_, process_p->name());
        break;
    }
}

//------------------------------------------------------------------------------
//"sc_reset::reset_signal_is"
//
// This static method will register the active process instance as being
// reset by the sc_signal<bool> whose interface has been supplied. If no
// sc_reset object instance has been attached to the sc_signal<bool> yet, it
// will be created and attached. The active process instance is pushed into
// the list of processes that the sc_reset object instance should notify if
// the value of the reset signal changes.
//
// Arguments:
//     async = true if the reset signal is asynchronous, false if not.
//     iface = interface for the reset signal.
//     level = is the level at which reset is active, either true or false.
// Notes:
//   (1) If reset is asserted we tell the process that it is in reset
//       initially.
//------------------------------------------------------------------------------
void sc_reset::reset_signal_is( 
    bool async, const sc_signal_in_if<bool>& iface, bool level )
{
    sc_process_b*   process_p;    // process adding reset for.
    sc_reset_target reset_target; // entry to build for the process.
    sc_reset*       reset_p;      // reset object.

    process_p = sc_process_b::last_created_process_base();
    assert( process_p );
    process_p->m_has_reset_signal = true;
    switch ( process_p->proc_kind() )
    {
      case SC_METHOD_PROC_:
      case SC_CTHREAD_PROC_:
      case SC_THREAD_PROC_:
	reset_p = iface.is_reset();
	process_p->m_resets.push_back(reset_p);
        reset_target.m_async = async; 
	reset_target.m_level = level;
	reset_target.m_process_p = process_p;
	reset_p->m_targets.push_back(reset_target);
	if ( iface.read() == level ) process_p->initially_in_reset( async );
        break;
      default:
        SC_REPORT_ERROR(SC_ID_UNKNOWN_PROCESS_TYPE_, process_p->name());
        break;
    }
}

} // namespace sc_core

// $Log: sc_reset.cpp,v $
// Revision 1.16  2011/08/26 20:46:10  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 1.15  2011/08/24 22:05:51  acg
//  Torsten Maehne: initialization changes to remove warnings.
//
// Revision 1.14  2011/04/08 22:37:34  acg
//  Andy Goodrich: documentation of the reset mechanism and additional
//  documentation of methods. Removal of check for SC_METHODs in
//  sc_reset_signal_is() that should not have been there.
//
// Revision 1.13  2011/03/20 15:13:01  acg
//  Andy Goodrich: set the reset flag for async_reset_signal_is to catch
//  the suspend() corner case.
//
// Revision 1.12  2011/03/20 13:43:23  acg
//  Andy Goodrich: added async_signal_is() plus suspend() as a corner case.
//
// Revision 1.11  2011/03/06 19:57:11  acg
//  Andy Goodrich: refinements for the illegal suspend - synchronous reset
//  interaction.
//
// Revision 1.10  2011/02/18 20:27:14  acg
//  Andy Goodrich: Updated Copyrights.
//
// Revision 1.9  2011/02/13 21:47:37  acg
//  Andy Goodrich: update copyright notice.
//
// Revision 1.8  2011/02/01 21:08:26  acg
//  Andy Goodrich: new multiple reset support.
//
// Revision 1.7  2011/01/06 18:04:38  acg
//  Andy Goodrich: removed commented out code.
//
// Revision 1.6  2010/12/07 20:09:13  acg
// Andy Goodrich: removed sc_signal overloads since already have sc_signal_in_if overloads.
//
// Revision 1.5  2010/11/20 17:10:56  acg
//  Andy Goodrich: reset processing changes for new IEEE 1666 standard.
//
// Revision 1.4  2009/05/22 16:06:29  acg
//  Andy Goodrich: process control updates.
//
// Revision 1.3  2009/03/12 22:59:58  acg
//  Andy Goodrich: updates for 2.4 stuff.
//
// Revision 1.2  2008/05/22 17:06:26  acg
//  Andy Goodrich: updated copyright notice to include 2008.
//
// Revision 1.1.1.1  2006/12/15 20:20:05  acg
// SystemC 2.3
//
// Revision 1.7  2006/12/02 20:58:19  acg
//  Andy Goodrich: updates from 2.2 for IEEE 1666 support.
//
// Revision 1.5  2006/04/11 23:13:21  acg
//   Andy Goodrich: Changes for reduced reset support that only includes
//   sc_cthread, but has preliminary hooks for expanding to method and thread
//   processes also.
//
// Revision 1.4  2006/01/24 20:49:05  acg
// Andy Goodrich: changes to remove the use of deprecated features within the
// simulator, and to issue warning messages when deprecated features are used.
//
// Revision 1.3  2006/01/13 18:44:30  acg
// Added $Log to record CVS changes into the source.
//