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RIOT/tests/sys/busy_wait/main.c
2024-01-11 13:02:56 +01:00

51 lines
1.2 KiB
C

/*
* Copyright (C) 2024 ML!PA Consulting GmbH
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup tests
* @{
*
* @file
* @brief Busy Wait loop Test Application
*
* This can be used to determine `CPU_CYCLES_PER_LOOP` by
* comparing the time the busy wait loop took with the
* actual µsec timer.
*
* @author Benjamin Valentin <benjamin.valentin@ml-pa.com>
* @}
*/
#include <stdio.h>
#include "busy_wait.h"
#include "ztimer/stopwatch.h"
static inline void _measure_interval(ztimer_stopwatch_t *clock, unsigned usec)
{
unsigned usec_real;
printf("waiting for %u µs…\n", usec);
ztimer_stopwatch_start(clock);
busy_wait_us(usec);
usec_real = ztimer_stopwatch_measure(clock);
printf("took %u µs (diff: %d µs)\n", usec_real, (int)usec_real - usec);
}
int main(void)
{
ztimer_stopwatch_t clock;
ztimer_stopwatch_init(ZTIMER_USEC, &clock);
_measure_interval(&clock, 10);
_measure_interval(&clock, 100);
_measure_interval(&clock, 1000);
_measure_interval(&clock, 10000);
return 0;
}