chrono.cpp

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/*
 * This file is part of the µOS++ project (https://micro-os-plus.github.io/).
 * Copyright (c) 2016-2025 Liviu Ionescu. All rights reserved.
 *
 * Permission to use, copy, modify, and/or distribute this software
 * for any purpose is hereby granted, under the terms of the MIT license.
 *
 * If a copy of the license was not distributed with this file, it can
 * be obtained from https://opensource.org/licenses/mit.
 */
 
#include <cmsis-plus/rtos/os.h>
#include <cmsis-plus/estd/chrono>
 
// ----------------------------------------------------------------------------
 
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wc++98-compat"
#endif
 
// ----------------------------------------------------------------------------
 
namespace os
{
  namespace estd
  {
    namespace chrono
    {
 
      // ----------------------------------------------------------------------
 
      using namespace os;
 
      // Number of seconds from epoch (1 January 1970 00:00:00 UTC)
      // when the system was started.
      // Must be set during startup by reading the RTC.
      // uint64_t startup_absolute_seconds;
 
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Waggregate-return"
#endif
 
      // ======================================================================
 
      systick_clock::time_point
      systick_clock::now () noexcept
      {
        const auto ticks = rtos::sysclock.now ();
        return time_point{ duration{ ticks } };
      }
 
      // ======================================================================
 
      realtime_clock::time_point
      realtime_clock::now () noexcept
      {
        const auto secs = rtos::rtclock.now ();
        return time_point{ duration{ secs } };
      }
 
      realtime_clock::time_point realtime_clock::startup_time_point;
 
      // ======================================================================
 
      system_clock::time_point
      system_clock::now () noexcept
      {
        const auto ticks = rtos::sysclock.now ();
        return time_point{
          duration{
              systicks{ ticks }
              + realtime_clock::startup_time_point.time_since_epoch () //
          } //
        };
      }
 
#pragma GCC diagnostic push
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wuseless-cast"
#endif
 
      time_t
      system_clock::to_time_t (const time_point& t) noexcept
      {
        return time_t (std::chrono::duration_cast<std::chrono::seconds> (
                           t.time_since_epoch ())
                           .count ());
      }
 
#pragma GCC diagnostic pop
 
      system_clock::time_point
      system_clock::from_time_t (time_t t) noexcept
      {
        return system_clock::time_point (std::chrono::seconds (t));
      }
 
      // ======================================================================
 
      high_resolution_clock::time_point
      high_resolution_clock::now () noexcept
      {
        auto cycles = rtos::hrclock.now ();
 
#pragma GCC diagnostic push
#if defined(__clang__)
// error: 'long long' is incompatible with C++98
// [-Werror,-Wc++98-compat-pedantic]
#pragma clang diagnostic ignored "-Wc++98-compat-pedantic"
#endif
        // The duration is the number of sum of SysTick ticks plus the current
        // count of CPU cycles (computed from the SysTick counter).
        // Notice: a more exact solution would be to compute
        // ticks * divisor + cycles, but this severely reduces the
        // range of ticks.
        return time_point{
          duration{
              duration{ cycles * 1000000000ULL
                        / rtos::hrclock.input_clock_frequency_hz () }
              + realtime_clock::startup_time_point.time_since_epoch () } //
        };
#pragma GCC diagnostic pop
      }
 
#pragma GCC diagnostic pop
 
      // ----------------------------------------------------------------------
 
    } /* namespace chrono */
  } /* namespace estd */
} /* namespace os */
 
// ----------------------------------------------------------------------------