text: /**
   * \file timing.h
   *
   * \brief Portable interface to the CPU cycle counter
   *
   *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
   *  SPDX-License-Identifier: Apache-2.0
   *
   *  Licensed under the Apache License, Version 2.0 (the "License"); you may
   *  not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *  http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   *  This file is part of mbed TLS (https://tls.mbed.org)
   */
  #ifndef MBEDTLS_TIMING_H
  #define MBEDTLS_TIMING_H
  
  #if !defined(MBEDTLS_CONFIG_FILE)
  #include "mbedtls_config.h"
  #else
  #include MBEDTLS_CONFIG_FILE
  #endif
  
  #if !defined(MBEDTLS_TIMING_ALT)
  // Regular implementation
  //
  
  #include <stdint.h>
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /**
   * \brief          timer structure
   */
  struct mbedtls_timing_hr_time
  {
      unsigned char opaque[32];
  };
  
  /**
   * \brief          Context for mbedtls_timing_set/get_delay()
   */
  typedef struct
  {
      struct mbedtls_timing_hr_time   timer;
      uint32_t                        int_ms;
      uint32_t                        fin_ms;
  } mbedtls_timing_delay_context;
  
  extern volatile int mbedtls_timing_alarmed;
  
  /**
   * \brief          Return the CPU cycle counter value
   *
   * \warning        This is only a best effort! Do not rely on this!
   *                 In particular, it is known to be unreliable on virtual
   *                 machines.
   */
  unsigned long mbedtls_timing_hardclock( void );
  
  /**
   * \brief          Return the elapsed time in milliseconds
   *
   * \param val      points to a timer structure
   * \param reset    if set to 1, the timer is restarted
   */
  unsigned long mbedtls_timing_get_timer( struct mbedtls_timing_hr_time *val, int reset );
  
  /**
   * \brief          Setup an alarm clock
   *
   * \param seconds  delay before the "mbedtls_timing_alarmed" flag is set
   *
   * \warning        Only one alarm at a time  is supported. In a threaded
   *                 context, this means one for the whole process, not one per
   *                 thread.
   */
  void mbedtls_set_alarm( int seconds );
  
  /**
   * \brief          Set a pair of delays to watch
   *                 (See \c mbedtls_timing_get_delay().)
   *
   * \param data     Pointer to timing data
   *                 Must point to a valid \c mbedtls_timing_delay_context struct.
   * \param int_ms   First (intermediate) delay in milliseconds.
   * \param fin_ms   Second (final) delay in milliseconds.
   *                 Pass 0 to cancel the current delay.
   */
  void mbedtls_timing_set_delay( void *data, uint32_t int_ms, uint32_t fin_ms );
  
  /**
   * \brief          Get the status of delays
   *                 (Memory helper: number of delays passed.)
   *
   * \param data     Pointer to timing data
   *                 Must point to a valid \c mbedtls_timing_delay_context struct.
   *
   * \return         -1 if cancelled (fin_ms = 0)
   *                  0 if none of the delays are passed,
   *                  1 if only the intermediate delay is passed,
   *                  2 if the final delay is passed.
   */
  int mbedtls_timing_get_delay( void *data );
  
  #ifdef __cplusplus
  }
  #endif
  
  #else  /* MBEDTLS_TIMING_ALT */
  #include "mbedtls_timing_alt.h"
  #endif /* MBEDTLS_TIMING_ALT */
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #if defined(MBEDTLS_SELF_TEST)
  /**
   * \brief          Checkup routine
   *
   * \return         0 if successful, or 1 if a test failed
   */
  int mbedtls_timing_self_test( int verbose );
  #endif
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* timing.h */
  