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/*  timer.c

 *

 *  This file manages the interval timer on the PA-RISC.

 *

 *  NOTE: It is important that the timer start/stop overhead be

 *        determined when porting or modifying this code.

 *

 *  COPYRIGHT (c) 1989-1999.

 *  On-Line Applications Research Corporation (OAR).

 *

 *  The license and distribution terms for this file may be

 *  found in the file LICENSE in this distribution or at

 *  http://www.OARcorp.com/rtems/license.html.

 *

 *  $Id: timer.c,v 1.2 2001-09-27 12:01:15 chris Exp $

 */

#include <bsp.h>

#include <time.h>

#include <sys/time.h>

struct timeval  Timer_start;

struct timeval  Timer_stop;

struct timezone Time_zone;

rtems_boolean   Timer_driver_Find_average_overhead;

void Timer_initialize()

{

   gettimeofday( &Timer_start, &Time_zone );

}

#define AVG_OVERHEAD      0  /* It typically takes xxx microseconds */

                             /* (XX countdowns) to start/stop the timer. */

#define LEAST_VALID       10 /* Don't trust a value lower than this */

int Read_timer()

{

  int total;

  gettimeofday( &Timer_stop, &Time_zone );

  if ( Timer_stop.tv_sec == Timer_start.tv_sec )

    total = Timer_stop.tv_usec - Timer_start.tv_usec;

  else {

    total  = 1000000 - Timer_start.tv_usec;

    total += (Timer_stop.tv_sec - Timer_start.tv_sec - 1) * 1000000;

    total += Timer_stop.tv_usec;

  }

  if ( Timer_driver_Find_average_overhead == 1 )

      return total;          /* in countdown units */

  else {

    if ( total < LEAST_VALID )

        return 0;            /* below timer resolution */

    return total - AVG_OVERHEAD;

  }

}

rtems_status_code Empty_function( void )

{

  return RTEMS_SUCCESSFUL;

}

void Set_find_average_overhead(

  rtems_boolean find_flag

)

{

  Timer_driver_Find_average_overhead = find_flag;

}