Subversion Repositories openrisc_me

/*  Timer_init()

 *

 *  This routine initializes a timer in efi68k's DP8570A TCP

 *

 *  Input parameters:  NONE

 *

 *  Output parameters:  NONE

 *

 *  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 12:00:02 chris Exp $

 */

#include <bsp.h>

rtems_boolean Timer_driver_Find_average_overhead;

extern rtems_isr Clock_isr();

void Timer_initialize( void )

{

}

/*

 *  The following controls the behavior of Read_timer().

 *

 *  FIND_AVG_OVERHEAD *  instructs the routine to return the "raw" count.

 *

 *  AVG_OVEREHAD is the overhead for starting and stopping the timer.  It

 *  is usually deducted from the number returned.

 *

 *  LEAST_VALID is the lowest number this routine should trust.  Numbers

 *  below this are "noise" and zero is returned.

 */

#define AVG_OVERHEAD      0  /* It typically takes X.X microseconds */

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

                             /* This value is in microseconds. */

#define LEAST_VALID       1  /* Don't trust a clicks value lower than this */

/*

 * Return timer value in 1/2-microsecond units

 */

int Read_timer( void )

{

  rtems_unsigned32 total;

  total = 0;

  if ( Timer_driver_Find_average_overhead == 1 )

    return total;          /* in XXX microsecond units */

  if ( total < LEAST_VALID )

    return 0;            /* below timer resolution */

  return (total - AVG_OVERHEAD);

}

/*

 *  Empty function call used in loops to measure basic cost of looping

 *  in Timing Test Suite.

 */

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;

}