104 lines
3.5 KiB
C
104 lines
3.5 KiB
C
/****************************************************************************
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* sched/clock/clock_time2ticks.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <time.h>
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#include <assert.h>
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#include "clock/clock.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: clock_time2ticks
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*
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* Description:
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* Convert a timespec delay to system timer ticks. This function is
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* suitable for calculating relative time delays and does not depend on
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* the other clock_* logic.
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*
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* Input Parameters:
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* reltime - Convert this relative time to system clock ticks.
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* ticks - Return the converted number of ticks here.
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*
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* Returned Value:
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* Always returns OK
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*
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* Assumptions:
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*
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****************************************************************************/
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int clock_time2ticks(FAR const struct timespec *reltime,
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FAR sclock_t *ticks)
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{
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#ifdef CONFIG_HAVE_LONG_LONG
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int64_t relnsec;
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/* Convert the relative time into nanoseconds. The range of the int64_t
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* is sufficiently large that there is no real need for range checking.
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*/
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relnsec = (int64_t)reltime->tv_sec * NSEC_PER_SEC +
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(int64_t)reltime->tv_nsec;
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/* Convert nanoseconds to clock ticks, rounding up to the smallest integer
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* that is greater than or equal to the exact number of tick.
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*/
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*ticks = (sclock_t)((relnsec + NSEC_PER_TICK - 1) / NSEC_PER_TICK);
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return OK;
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#else
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int32_t relusec;
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/* This function uses an int32_t to only the relative time in microseconds.
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* that means that the maximum supported relative time is 2,147,487.647
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* seconds
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*/
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#if 0 // overkill
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DEBUGASSERT(reltime->tv_sec < 2147487 ||
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reltime->tv_sec == 2147487 &&
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reltime->tv_nsec <= 647 * NSEC_PER_MSEC);
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#endif
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/* Convert the relative time into microseconds, rounding up to the smallest
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* value that is greater than or equal to the exact number of microseconds.
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*/
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relusec = reltime->tv_sec * USEC_PER_SEC +
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(reltime->tv_nsec + NSEC_PER_USEC - 1) / NSEC_PER_USEC;
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/* Convert microseconds to clock ticks, rounding up to the smallest integer
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* that is greater than or equal to the exact number of tick.
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*/
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*ticks = (sclock_t)((relusec + USEC_PER_TICK - 1) / USEC_PER_TICK);
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return OK;
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#endif
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}
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