252 lines
9.3 KiB
C
252 lines
9.3 KiB
C
/****************************************************************************
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* include/nuttx/clock.h
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*
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* Copyright (C) 2007-2009, 2011-2012 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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#ifndef _INCLUDE_NUTTX_CLOCK_H
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#define _INCLUDE_NUTTX_CLOCK_H
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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 <nuttx/compiler.h>
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/****************************************************************************
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* Pro-processor Definitions
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****************************************************************************/
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/* Configuration ************************************************************/
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/* Efficient, direct access to OS global timer variables will be supported
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* if the execution environment has direct access to kernel global data.
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* The code in this execution context can access the kernel global data
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* directly if: (1) this is an un-protected, non-kernel build, or (2)
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* this code is being built for execution within the kernel.
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*/
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#undef __HAVE_KERNEL_GLOBALS
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#if !defined(CONFIG_NUTTX_KERNEL) || defined(__KERNEL__)
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# define __HAVE_KERNEL_GLOBALS 1
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#else
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# define __HAVE_KERNEL_GLOBALS 0
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#endif
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/* If CONFIG_SYSTEM_TIME64 is selected and the CPU supports long long types,
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* then a 64-bit system time will be used.
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*/
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#ifndef CONFIG_HAVE_LONG_LONG
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# undef CONFIG_SYSTEM_TIME64
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#endif
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/* Timing constants *********************************************************/
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#define NSEC_PER_SEC 1000000000
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#define USEC_PER_SEC 1000000
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#define MSEC_PER_SEC 1000
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#define DSEC_PER_SEC 10
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#define NSEC_PER_DSEC 100000000
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#define USEC_PER_DSEC 100000
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#define MSEC_PER_DSEC 100
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#define NSEC_PER_MSEC 1000000
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#define USEC_PER_MSEC 1000
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#define NSEC_PER_USEC 1000
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/* The interrupt interval of the system timer is given by MSEC_PER_TICK.
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* This is the expected number of milliseconds between calls from the
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* processor-specific logic to sched_process_timer(). The default value
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* of MSEC_PER_TICK is 10 milliseconds (100KHz). However, this default
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* setting can be overridden by defining the interval in milliseconds as
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* CONFIG_MSEC_PER_TICK in the board configuration file.
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*
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* The following calculations are only accurate when (1) there is no
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* truncation involved and (2) the underlying system timer is an even
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* multiple of milliseconds. If (2) is not true, you will probably want
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* to redefine all of the following.
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*/
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#ifdef CONFIG_MSEC_PER_TICK
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# define MSEC_PER_TICK (CONFIG_MSEC_PER_TICK)
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#else
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# define MSEC_PER_TICK (10)
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#endif
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#define TICK_PER_DSEC (MSEC_PER_DSEC / MSEC_PER_TICK) /* Truncates! */
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#define TICK_PER_SEC (MSEC_PER_SEC / MSEC_PER_TICK) /* Truncates! */
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#define NSEC_PER_TICK (MSEC_PER_TICK * NSEC_PER_MSEC) /* Exact */
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#define USEC_PER_TICK (MSEC_PER_TICK * USEC_PER_MSEC) /* Exact */
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#define NSEC2TICK(nsec) (((nsec)+(NSEC_PER_TICK/2))/NSEC_PER_TICK) /* Rounds */
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#define USEC2TICK(usec) (((usec)+(USEC_PER_TICK/2))/USEC_PER_TICK) /* Rounds */
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#define MSEC2TICK(msec) (((msec)+(MSEC_PER_TICK/2))/MSEC_PER_TICK) /* Rounds */
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#define DSEC2TICK(dsec) MSEC2TICK((dsec)*MSEC_PER_DSEC)
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#define SEC2TICK(sec) MSEC2TICK((sec)*MSEC_PER_SEC)
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#define TICK2NSEC(tick) ((tick)*NSEC_PER_TICK) /* Exact */
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#define TICK2USEC(tick) ((tick)*USEC_PER_TICK) /* Exact */
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#define TICK2MSEC(tick) ((tick)*MSEC_PER_TICK) /* Exact */
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#define TICK2DSEC(tick) (((tick)+(TICK_PER_DSEC/2))/TICK_PER_DSEC) /* Rounds */
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#define TICK2SEC(tick) (((tick)+(TICK_PER_SEC/2))/TICK_PER_SEC) /* Rounds */
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/****************************************************************************
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* Global Data
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****************************************************************************/
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#if !defined(CONFIG_DISABLE_CLOCK)
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/* Access to raw system clock ***********************************************/
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/* Direct access to the system timer/counter is supported only if (1) the
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* system timer counter is available (i.e., we are not configured to use
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* a hardware periodic timer), and (2) the execution environment has direct
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* access to kernel global data
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*/
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#if __HAVE_KERNEL_GLOBALS
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# ifdef CONFIG_SYSTEM_TIME64
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extern volatile uint64_t g_system_timer;
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#define clock_systimer() (uint32_t)(g_system_timer & 0x00000000ffffffff)
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#define clock_systimer64() g_system_timer
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# else
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extern volatile uint32_t g_system_timer;
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#define clock_systimer() g_system_timer
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# endif
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#endif
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/****************************************************************************
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* Global Function Prototypes
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****************************************************************************/
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#ifdef __cplusplus
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#define EXTERN extern "C"
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extern "C" {
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#else
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#define EXTERN extern
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#endif
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/****************************************************************************
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* Function: clock_synchronize
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*
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* Description:
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* Synchronize the system timer to a hardware RTC. This operation is
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* normally performed automatically by the system during clock
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* initialization. However, the user may also need to explicitly re-
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* synchronize the system timer to the RTC under certain conditions where
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* the system timer is known to be in error. For example, in certain low-
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* power states, the system timer may be stopped but the RTC will continue
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* keep correct time. After recovering from such low-power state, this
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* function should be called to restore the correct system time.
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*
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* Calling this function could result in system time going "backward" in
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* time, especially with certain lower resolution RTC implementations.
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* Time going backward could have bad consequences if there are ongoing
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* timers and delays. So use this interface with care.
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*
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* Parameters:
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* None
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*
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* Return Value:
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* None
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*
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* Assumptions:
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*
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****************************************************************************/
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#ifdef CONFIG_RTC
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EXTERN void clock_synchronize(void);
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#endif
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/****************************************************************************
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* Function: clock_systimer
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*
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* Description:
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* Return the current value of the 32-bit system timer counter. Indirect
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* access to the system timer counter is required through this function if
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* the execution environment does not have direct access to kernel global
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* data
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*
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* Parameters:
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* None
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*
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* Return Value:
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* The current value of the system timer counter
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*
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* Assumptions:
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*
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****************************************************************************/
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#if !__HAVE_KERNEL_GLOBALS
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# ifdef CONFIG_SYSTEM_TIME64
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# define clock_systimer() (uint32_t)(clock_systimer64() & 0x00000000ffffffff)
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# else
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EXTERN uint32_t clock_systimer(void);
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# endif
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#endif
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/****************************************************************************
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* Function: clock_systimer64
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*
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* Description:
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* Return the current value of the 64-bit system timer counter. Indirect
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* access to the system timer counter is required through this function if
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* the execution environment does not have direct access to kernel global
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* data
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*
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* Parameters:
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* None
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*
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* Return Value:
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* The current value of the system timer counter
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*
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* Assumptions:
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*
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****************************************************************************/
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#if !__HAVE_KERNEL_GLOBALS && defined(CONFIG_SYSTEM_TIME64)
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EXTERN uint64_t clock_systimer64(void);
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#endif
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#undef EXTERN
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#ifdef __cplusplus
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}
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#endif
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#endif /* !CONFIG_DISABLE_CLOCK */
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#endif /* _INCLUDE_NUTTX_CLOCK_H */
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