xref: /gem5/src/systemc/tests/systemc/1666-2011-compliance/stepwise_simulation/stepwise_simulation.cpp

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

  stepwise_simulation.cpp -- Test step-wise simulation

  Original Author: Philipp A. Hartmann, OFFIS, 2011-01-21

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

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

  MODIFICATION LOG - modifiers, enter your name, affiliation, date and
  changes you are making here.

      Name, Affiliation, Date:
  Description of Modification:

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

#include <systemc.h>

const int num_events = 2;
const sc_time delay( 10, SC_NS );

//#define EXPLICIT_DELTA // should not modify the trace
#define DELAYED_EVENTS

SC_MODULE(echo)
{
  sc_event ev[num_events];
  SC_CTOR(echo)
    : self_trigger(3)
  {
    SC_METHOD(do_print);
#   ifdef DELAYED_EVENTS
      dont_initialize();
#   endif
      for( int i=0; i<num_events; ++i )
        sensitive << ev[i];
  }

  void do_print()
  {
    std::cout << "`" << sc_get_current_process_handle().name()
              << "' triggered at " << sc_time_stamp()
              << " - delta: " << sc_delta_count()
              << std::endl;

    if( --self_trigger > 1 )
      next_trigger( delay/2 );
    else if( self_trigger == 1 )
      next_trigger( SC_ZERO_TIME );
    else
      self_trigger = 3;

  }
  int self_trigger;
};

void do_step( sc_time const & step )
{
    sc_dt::uint64 delta       = sc_delta_count();
    static bool   start_delta = ( delta == 0 ) && ( step == SC_ZERO_TIME );
    std::cout
       << " ----- running for "
       << ( ( step == SC_ZERO_TIME ) ? "delta" : step.to_string() )
       << std::endl;

    sc_time start = sc_time_stamp();
    if( step > SC_ZERO_TIME )
    {
      std::cout << "   --- No-op start (warning) - ";
      sc_start( step / 2, SC_EXIT_ON_STARVATION );
      sc_assert( start == sc_time_stamp() );

      sc_start( step / 2, SC_RUN_TO_TIME );
      sc_assert( start + step / 2 == sc_time_stamp() );

      sc_start( step / 2 ); // complete step
    }
    else
    {
      sc_start( SC_ZERO_TIME );
    }
    sc_assert( start + step == sc_time_stamp() );

    std::cout
       << "    -- stopped at - "
       << sc_time_stamp() << " - delta: " << sc_delta_count()
       << std::endl;

    // delta has only increased, when a delta has been run
    sc_assert( sc_delta_count()
                 == delta + ( !start_delta && step == SC_ZERO_TIME ) );
    start_delta = false;
}

int sc_main(int, char*[])
{
  sc_assert( !sc_pending_activity() );
  sc_assert( sc_time_to_pending_activity()
             == sc_max_time() - sc_time_stamp() );

  sc_signal<bool> toggle("toggle");
  echo dut("echo");

  // notify future events
  for( int i=0; i<num_events; ++i )
    dut.ev[i].notify( (i+1) * delay );

  sc_assert( sc_pending_activity_at_future_time() );
  sc_assert( sc_time_to_pending_activity() == delay );

  do_step( SC_ZERO_TIME ); // elaborate

  while( sc_pending_activity() )
  {
    sc_assert( sc_pending_activity_at_current_time()
               || sc_time_to_pending_activity() > SC_ZERO_TIME );

    sc_assert( sc_pending_activity_at_future_time()
               || sc_time_to_pending_activity() == SC_ZERO_TIME );

    // run single (time) step
    do_step( sc_time_to_pending_activity() );

#   ifdef EXPLICIT_DELTA
      // run remaining current deltas (optional)
      while( sc_pending_activity_at_current_time() ) {
        sc_assert( sc_time_to_pending_activity() == SC_ZERO_TIME );
        do_step( SC_ZERO_TIME );
      }
#   endif // EXPLICIT_DELTA
  }

  // force one empty evaluate (w/ non-empty update)
  toggle.write( !toggle.read() );
  sc_assert(  sc_pending_activity_at_current_time() );
  sc_start( SC_ZERO_TIME );

  sc_assert( !sc_pending_activity() );
  sc_assert( sc_time_to_pending_activity()
             == sc_max_time() - sc_time_stamp() );

  std::cout << "Success" << std::endl;
  return 0;
}