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/* timer.c
*
* This file implements a benchmark timer using timer 2.
*
* COPYRIGHT (c) 1989-1998.
* 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.rtems.com/license/LICENSE.
*
* Ported to LEON implementation of the SPARC by On-Line Applications
* Research Corporation (OAR) under contract to the European Space
* Agency (ESA).
*
* LEON modifications of respective RTEMS file: COPYRIGHT (c) 1995.
* European Space Agency.
*
* $Id$
*/
#include <bsp.h>
rtems_boolean Timer_driver_Find_average_overhead;
rtems_boolean Timer_driver_Is_initialized = FALSE;
extern volatile LEON3_Timer_Regs_Map *LEON3_Timer_Regs;
void Timer_initialize()
{
/*
* Timer runs long and accurate enough not to require an interrupt.
*/
if (LEON3_Timer_Regs) {
if ( Timer_driver_Is_initialized == FALSE ) {
/* approximately 1 us per countdown */
LEON3_Timer_Regs->reload_t1 = 0xffffff;
LEON3_Timer_Regs->value_t1 = 0xffffff;
} else {
Timer_driver_Is_initialized = TRUE;
}
LEON3_Timer_Regs->conf_t1 = LEON3_GPTIMER_EN | LEON3_GPTIMER_LD;
}
}
#define AVG_OVERHEAD 3 /* It typically takes 3.0 microseconds */
/* to start/stop the timer. */
#define LEAST_VALID 2 /* Don't trust a value lower than this */
int Read_timer()
{
rtems_unsigned32 total;
if (LEON3_Timer_Regs) {
total = LEON3_Timer_Regs->value_t1;
total = 0xffffff - total;
if ( Timer_driver_Find_average_overhead == 1 )
return total; /* in one microsecond units */
if ( total < LEAST_VALID )
return 0; /* below timer resolution */
return total - AVG_OVERHEAD;
}
return 0;
}
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;
}
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