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/**
* @file
*
* @ingroup RTEMSBSPsOR1K
*
* @brief Benchmark timer support.
*/
/*
* Copyright (c) 2014-2015 by Hesham ALMatary
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE
*/
#include <rtems.h>
#include <rtems/btimer.h>
#include <bsp/generic_or1k.h>
#include <rtems/score/or1k-utility.h>
#define OR1K_NANOSECONDS_PER_CLK_CYCLE 10
static bool benchmark_timer_find_average_overhead = false;
static uint64_t benchmark_timer_base;
void benchmark_timer_initialize(void)
{
benchmark_timer_base = _OR1K_mfspr(CPU_OR1K_SPR_TTCR);
}
#define AVG_OVERHEAD 0
#define LEAST_VALID 1
benchmark_timer_t benchmark_timer_read( void )
{
uint64_t clicks;
uint64_t total;
uint64_t delta;
/*
* Read the timer and see how many clicks (clock cycles)
* has passed since timer initialization.
*/
clicks = _OR1K_mfspr(CPU_OR1K_SPR_TTCR);
delta = clicks - benchmark_timer_base;
/* total in nanoseconds */
total = OR1K_NANOSECONDS_PER_CLK_CYCLE * (delta);
if ( benchmark_timer_find_average_overhead == true )
return total; /* in nanoseconds microsecond units */
else {
if ( total < LEAST_VALID )
return 0; /* below timer resolution */
return (total - AVG_OVERHEAD);
}
}
void benchmark_timer_disable_subtracting_average_overhead(bool find_flag)
{
benchmark_timer_find_average_overhead = find_flag;
}
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