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/*
ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
2011,2012,2013 Giovanni Di Sirio.
This file is part of ChibiOS/RT.
ChibiOS/RT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
ChibiOS/RT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file chtm.c
* @brief Time Measurement module code.
*
* @addtogroup time_measurement
* @details Time Measurement APIs and services.
* @{
*/
#include "ch.h"
#if CH_CFG_USE_TM || defined(__DOXYGEN__)
/*===========================================================================*/
/* Module local definitions. */
/*===========================================================================*/
/*===========================================================================*/
/* Module exported variables. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local types. */
/*===========================================================================*/
/*===========================================================================*/
/* Module local variables. */
/*===========================================================================*/
/**
* @brief Measurement calibration value.
*/
static rtcnt_t measurement_offset;
/*===========================================================================*/
/* Module local functions. */
/*===========================================================================*/
static inline void tm_stop(time_measurement_t *tmp, rtcnt_t now) {
tmp->last = now - tmp->last - measurement_offset;
tmp->cumulative += tmp->last;
if (tmp->last > tmp->worst)
tmp->worst = tmp->last;
else if (tmp->last < tmp->best)
tmp->best = tmp->last;
}
/*===========================================================================*/
/* Module exported functions. */
/*===========================================================================*/
/**
* @brief Initializes the time measurement unit.
*
* @init
*/
void _tm_init(void) {
time_measurement_t tm;
/* Time Measurement subsystem calibration, it does a null measurement
and calculates the call overhead which is subtracted to real
measurements.*/
measurement_offset = 0;
chTMObjectInit(&tm);
chTMStartX(&tm);
chTMStopX(&tm);
measurement_offset = tm.last;
}
/**
* @brief Realtime window test.
* @details This function verifies if the current realtime counter value
* lies within the specified range or not. The test takes care
* of the realtime counter wrapping to zero on overflow.
* @note When start==end then the function returns always true because the
* whole time range is specified.
*
* @param[in] cnt the counter value to be tested
* @param[in] start the start of the time window (inclusive)
* @param[in] end the end of the time window (non inclusive)
* @retval true current time within the specified time window.
* @retval false current time not within the specified time window.
*
* @xclass
*/
bool chTMIsCounterWithinX(rtcnt_t cnt, rtcnt_t start, rtcnt_t end) {
return end > start ? (cnt >= start) && (cnt < end) :
(cnt >= start) || (cnt < end);
}
/**
* @brief Polled delay.
* @note The real delay is always few cycles in excess of the specified
* value.
*
* @param[in] cycles number of cycles
*
* @xclass
*/
void chTMPolledDelayX(rtcnt_t cycles) {
rtcnt_t start = chSysGetRealtimeCounterX();
rtcnt_t end = start + cycles;
while (chTMIsCounterWithinX(chSysGetRealtimeCounterX(), start, end))
;
}
/**
* @brief Initializes a @p TimeMeasurement object.
*
* @param[out] tmp pointer to a @p TimeMeasurement structure
*
* @init
*/
void chTMObjectInit(time_measurement_t *tmp) {
tmp->best = (rtcnt_t)-1;
tmp->worst = (rtcnt_t)0;
tmp->cumulative = (rtcnt_t)0;
tmp->last = (rtcnt_t)0;
}
/**
* @brief Starts a measurement.
* @pre The @p time_measurement_t structure must be initialized.
*
* @param[in,out] tmp pointer to a @p TimeMeasurement structure
*
* @xclass
*/
NOINLINE void chTMStartX(time_measurement_t *tmp) {
tmp->last = chSysGetRealtimeCounterX();
}
/**
* @brief Stops a measurement.
* @pre The @p time_measurement_t structure must be initialized.
*
* @param[in,out] tmp pointer to a @p time_measurement_t structure
*
* @xclass
*/
NOINLINE void chTMStopX(time_measurement_t *tmp) {
tm_stop(tmp, chSysGetRealtimeCounterX());
}
#endif /* CH_CFG_USE_TM */
/**
* @brief Stops a measurement and chains to the next one using the same time
* stamp.
*
* @param[in,out] tmp1 pointer to the @p time_measurement_t structure to be
* stopped
* @param[in,out] tmp2 pointer to the @p time_measurement_t structure to be
* started
*
*
* @xclass
*/
NOINLINE void chTMChainToX(time_measurement_t *tmp1,
time_measurement_t *tmp2) {
/* Starts new measurement.*/
tmp2->last = chSysGetRealtimeCounterX();
/* Stops previous measurement using the same time stamp.*/
tm_stop(tmp1, tmp2->last);
}
/** @} */
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