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PsRealTimeController.cxx

Go to the documentation of this file.

/*
 * This file is part of openMask © INRIA, CNRS, Universite de Rennes 1 1993-2002, thereinafter the Software
 * 
 * The Software has been developped within the Siames Project. 
 * INRIA, the University of Rennes 1 and CNRS jointly hold intellectual property rights
 * 
 * The Software has been registered with the Agence pour la Protection des
 * Programmes (APP) under registration number IDDN.FR.001.510008.00.S.P.2001.000.41200
 *  
 * This file may be distributed under the terms of the Q Public License
 * version 1.0 as defined by Trolltech AS of Norway and appearing in the file
 * LICENSE.QPL included in the packaging of this file.
 *
 * Licensees holding valid specific licenses issued by INRIA, CNRS or Université de Rennes 1 
 * for the software may use this file in accordance with that specific license
 *
 */
#ifdef _SGI
#include <PsRealTimeController.h>
#include <sys/time.h>
#include <sys/syssgi.h>
#include <unistd.h>

// PsController::PsController
//--------------------------------------------------------

PsRealTimeController::PsRealTimeController(PsObjectDescriptor & scenario, const PsDate & initialDate) 
:  PsController(scenario, initialDate)
{
}

//----------------------------------------------------------
// destructeur

PsRealTimeController::~PsRealTimeController() {
}

void PsRealTimeController::compute (){
   static long avance = 0 ;
   static timespec avant, apres;

   clock_gettime(CLOCK_SGI_CYCLE, &avant);

   PsController::compute ();

   //lecture des compteurs du pas de calcul
   clock_gettime(CLOCK_SGI_CYCLE, &apres);

   long duree = apres.tv_nsec - avant.tv_nsec ;
   if (duree < 0 ) duree =  apres.tv_nsec + ( LONG_MAX/2 - avant.tv_nsec ) ;

   //Les 4 lignes qui suivent sont une tentative primitive d'atteinte du temps réel
   avance += _stepPeriod * 1000  - duree / 1000 ;
   if (avance > 10000) {
      usleep( avance );
      clock_gettime(CLOCK_SGI_CYCLE, &apres);
      if (apres.tv_nsec > avant.tv_nsec) {
         avance = avance - (apres.tv_nsec - avant.tv_nsec) / 1000 ;
      }
      else {
         avance =  avance - (( LONG_MAX/2 - avant.tv_nsec ) + apres.tv_nsec ) / 1000 ;
      }
   }
}
#endif

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