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[/] [openrisc/] [trunk/] [rtos/] [rtems/] [c/] [src/] [lib/] [libbsp/] [m68k/] [efi332/] [timer/] [timer.c] - Blame information for rev 173

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1 30 unneback
/*  Timer_init()
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 *
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 *  This routine initializes a timer in efi68k's DP8570A TCP
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 *
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 *  Input parameters:  NONE
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 *
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 *  Output parameters:  NONE
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 *
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 *  NOTE: It is important that the timer start/stop overhead be
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 *        determined when porting or modifying this code.
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 *
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 *  COPYRIGHT (c) 1989-1999.
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 *  On-Line Applications Research Corporation (OAR).
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 *
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 *  The license and distribution terms for this file may be
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 *  found in the file LICENSE in this distribution or at
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 *  http://www.OARcorp.com/rtems/license.html.
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 *
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 *  $Id: timer.c,v 1.2 2001-09-27 12:00:02 chris Exp $
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 */
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#include <bsp.h>
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rtems_boolean Timer_driver_Find_average_overhead;
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extern rtems_isr Clock_isr();
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void Timer_initialize( void )
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{
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}
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/*
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 *  The following controls the behavior of Read_timer().
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 *
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 *  FIND_AVG_OVERHEAD *  instructs the routine to return the "raw" count.
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 *
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 *  AVG_OVEREHAD is the overhead for starting and stopping the timer.  It
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 *  is usually deducted from the number returned.
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 *
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 *  LEAST_VALID is the lowest number this routine should trust.  Numbers
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 *  below this are "noise" and zero is returned.
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 */
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#define AVG_OVERHEAD      0  /* It typically takes X.X microseconds */
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                             /* (Y countdowns) to start/stop the timer. */
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                             /* This value is in microseconds. */
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#define LEAST_VALID       1  /* Don't trust a clicks value lower than this */
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/*
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 * Return timer value in 1/2-microsecond units
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 */
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int Read_timer( void )
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{
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  rtems_unsigned32 total;
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  total = 0;
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  if ( Timer_driver_Find_average_overhead == 1 )
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    return total;          /* in XXX microsecond units */
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  if ( total < LEAST_VALID )
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    return 0;            /* below timer resolution */
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  return (total - AVG_OVERHEAD);
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}
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/*
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 *  Empty function call used in loops to measure basic cost of looping
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 *  in Timing Test Suite.
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 */
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rtems_status_code Empty_function(void)
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{
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    return RTEMS_SUCCESSFUL;
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}
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void Set_find_average_overhead(
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  rtems_boolean find_flag
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)
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{
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  Timer_driver_Find_average_overhead = find_flag;
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}

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