etl/test/test_atomic.cpp

/******************************************************************************
The MIT License(MIT)

Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com

Copyright(c) 2022 John Wellbelove

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files(the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
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The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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******************************************************************************/

#include "unit_test_framework.h"

#include "etl/platform.h"
#include "etl/enum_type.h"

#if defined(ETL_COMPILER_MICROSOFT)
  #include "etl/atomic/atomic_std.h"
#elif defined(ETL_COMPILER_GCC)
  #include "etl/atomic/atomic_gcc_sync.h"
#elif defined(ETL_COMPILER_CLANG)
  #include "etl/atomic/atomic_clang_sync.h"
#endif

#include <atomic>
#include <thread>

#if defined(ETL_TARGET_OS_WINDOWS)
  #include <Windows.h>
#endif

#define REALTIME_TEST 0

namespace
{
  struct Enum
  {
    enum enum_type
    {
      Zero = 0,
      One  = 1,
      Two  = 2
    };

    ETL_DECLARE_ENUM_TYPE(Enum, int)
    ETL_ENUM_TYPE(Zero, "0")
    ETL_ENUM_TYPE(One,  "1")
    ETL_ENUM_TYPE(Two,  "2")
    ETL_END_ENUM_TYPE
  };

  SUITE(test_atomic)
  {
    //*************************************************************************
    TEST(test_atomic_integer_is_lock_free)
    {
      std::atomic<int> compare;
      etl::atomic<int> test;

      CHECK_EQUAL(compare.is_lock_free(), test.is_lock_free());

#if ETL_HAS_ATOMIC_ALWAYS_LOCK_FREE
      CHECK_TRUE(etl::atomic<int>::is_always_lock_free);
      CHECK_TRUE(test.is_always_lock_free);
#endif
    }

    //*************************************************************************
    TEST(test_atomic_pointer_is_lock_free)
    {
      std::atomic<int*> compare;
      etl::atomic<int*> test;

      CHECK_EQUAL(compare.is_lock_free(), test.is_lock_free());

#if ETL_HAS_ATOMIC_ALWAYS_LOCK_FREE
      CHECK_TRUE(etl::atomic<int*>::is_always_lock_free);
      CHECK_TRUE(test.is_always_lock_free);
#endif
    }

#if ETL_HAS_ATOMIC_ALWAYS_LOCK_FREE
    //*************************************************************************
    TEST(test_atomic_is_always_lock_free)
    {
      struct S
      {
        int a;
        int b;
        int c;
      };

      CHECK_TRUE(etl::atomic<int>::is_always_lock_free);
      CHECK_TRUE(etl::atomic<int*>::is_always_lock_free);
      CHECK_FALSE(etl::atomic<S>::is_always_lock_free);
    }
#endif

    //*************************************************************************
    TEST(test_atomic_integer_load)
    {
      std::atomic<int> compare(1);
      etl::atomic<int> test(1);

      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_enum_load)
    {
      std::atomic<Enum> compare(Enum::One);
      etl::atomic<Enum> test(Enum::One);

      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_pointer_load)
    {
      int i;

      std::atomic<int*> compare(&i);
      etl::atomic<int*> test(&i);

      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_bool_load)
    {
      std::atomic<bool> compare(true);
      etl::atomic<bool> test(true);

      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_integer_store)
    {
      std::atomic<int> compare(1);
      etl::atomic<int> test(1);

      compare.store(2);
      test.store(2);
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_enum_store)
    {
      std::atomic<Enum> compare(Enum::One);
      etl::atomic<Enum> test(Enum::One);

      compare.store(Enum::Two);
      test.store(Enum::Two);
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_pointer_store)
    {
      int i;
      int j;

      std::atomic<int*> compare(&i);
      etl::atomic<int*> test(&i);

      compare.store(&j);
      test.store(&j);
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_bool_store)
    {
      std::atomic<bool> compare(false);
      etl::atomic<bool> test(false);

      compare.store(true);
      test.store(true);
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_integer_assignment)
    {
      std::atomic<int> compare(1);
      etl::atomic<int> test(1);

      compare = 2;
      test    = 2;
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_enum_assignment)
    {
      std::atomic<Enum> compare(Enum::One);
      etl::atomic<Enum> test(Enum::One);

      compare = Enum::Two;
      test    = Enum::Two;
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_pointer_assignment)
    {
      int i;
      int j;

      std::atomic<int*> compare(&i);
      etl::atomic<int*> test(&i);

      compare = &j;
      test    = &j;
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_bool_assignment)
    {
      std::atomic<bool> compare(false);
      etl::atomic<bool> test(false);

      compare = true;
      test    = true;
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_operator_integer_pre_increment)
    {
      std::atomic<int> compare(1);
      etl::atomic<int> test(1);

      CHECK_EQUAL(++compare, ++test);
      CHECK_EQUAL(++compare, ++test);
    }

    //*************************************************************************
    TEST(test_atomic_operator_integer_post_increment)
    {
      std::atomic<int> compare(1);
      etl::atomic<int> test(1);

      CHECK_EQUAL(compare++, test++);
      CHECK_EQUAL(compare++, test++);
    }

    //*************************************************************************
    TEST(test_atomic_operator_integer_pre_decrement)
    {
      std::atomic<int> compare(1);
      etl::atomic<int> test(1);

      CHECK_EQUAL(--compare, --test);
      CHECK_EQUAL(--compare, --test);
    }

    //*************************************************************************
    TEST(test_atomic_operator_integer_post_decrement)
    {
      std::atomic<int> compare(1);
      etl::atomic<int> test(1);

      CHECK_EQUAL(compare--, test--);
      CHECK_EQUAL(compare--, test--);
    }

    //*************************************************************************
    TEST(test_atomic_operator_pointer_pre_increment)
    {
      int data[] = {1, 2, 3, 4};

      std::atomic<int*> compare(&data[0]);
      etl::atomic<int*> test(&data[0]);

      CHECK_EQUAL(++compare, ++test);
      CHECK_EQUAL(++compare, ++test);
    }

    //*************************************************************************
    TEST(test_atomic_operator_pointer_post_increment)
    {
      int data[] = {1, 2, 3, 4};

      std::atomic<int*> compare(&data[0]);
      etl::atomic<int*> test(&data[0]);

      CHECK_EQUAL(compare++, test++);
      CHECK_EQUAL(compare++, test++);
    }

    //*************************************************************************
    TEST(test_atomic_operator_pointer_pre_decrement)
    {
      int data[] = {1, 2, 3, 4};

      std::atomic<int*> compare(&data[3]);
      etl::atomic<int*> test(&data[3]);

      CHECK_EQUAL(--compare, --test);
      CHECK_EQUAL(--compare, --test);
    }

    //*************************************************************************
    TEST(test_atomic_operator_pointer_post_decrement)
    {
      int data[] = {1, 2, 3, 4};

      std::atomic<int*> compare(&data[3]);
      etl::atomic<int*> test(&data[3]);

      CHECK_EQUAL(compare--, test--);
      CHECK_EQUAL(compare--, test--);
    }

    //*************************************************************************
    TEST(test_atomic_operator_integer_fetch_add)
    {
      std::atomic<int> compare(1);
      etl::atomic<int> test(1);

      CHECK_EQUAL(compare.fetch_add(2), test.fetch_add(2));
    }

    //*************************************************************************
    TEST(test_atomic_operator_pointer_fetch_add)
    {
      int data[] = {1, 2, 3, 4};

      std::atomic<int*> compare(&data[0]);
      etl::atomic<int*> test(&data[0]);

      CHECK_EQUAL(compare.fetch_add(ptrdiff_t(10)), test.fetch_add(ptrdiff_t(10)));
    }

    //*************************************************************************
    TEST(test_atomic_operator_integer_plus_equals)
    {
      std::atomic<int> compare(1);
      etl::atomic<int> test(1);

      compare += 2;
      test += 2;

      CHECK_EQUAL(compare, test);
    }

    //*************************************************************************
    TEST(test_atomic_operator_pointer_plus_equals)
    {
      int data[] = {1, 2, 3, 4};

      std::atomic<int*> compare(&data[0]);
      etl::atomic<int*> test(&data[0]);

      compare += 2;
      test += 2;

      CHECK_EQUAL(compare, test);
    }

    //*************************************************************************
    TEST(test_atomic_operator_integer_minus_equals)
    {
      std::atomic<int> compare(1);
      etl::atomic<int> test(1);

      compare -= 2;
      test -= 2;

      CHECK_EQUAL(compare, test);
    }

    //*************************************************************************
    TEST(test_atomic_operator_pointer_minus_equals)
    {
      int data[] = {1, 2, 3, 4};

      std::atomic<int*> compare(&data[3]);
      etl::atomic<int*> test(&data[3]);

      compare -= 2;
      test -= 2;

      CHECK_EQUAL(compare, test);
    }

    //*************************************************************************
    TEST(test_atomic_operator_integer_and_equals)
    {
      std::atomic<int> compare(0x0000FFFFUL);
      etl::atomic<int> test(0x0000FFFFUL);

      compare &= 0x55AA55AAUL;
      test &= 0x55AA55AAUL;

      CHECK_EQUAL(compare, test);
    }

    //*************************************************************************
    TEST(test_atomic_operator_integer_or_equals)
    {
      std::atomic<int> compare(0x0000FFFFUL);
      etl::atomic<int> test(0x0000FFFFUL);

      compare |= 0x55AA55AAUL;
      test |= 0x55AA55AAUL;

      CHECK_EQUAL(compare, test);
    }

    //*************************************************************************
    TEST(test_atomic_operator_integer_xor_equals)
    {
      std::atomic<int> compare(0x0000FFFFUL);
      etl::atomic<int> test(0x0000FFFFUL);

      compare ^= 0x55AA55AAUL;
      test ^= 0x55AA55AAUL;

      CHECK_EQUAL(compare, test);
    }

    //*************************************************************************
    TEST(test_atomic_operator_integer_fetch_sub)
    {
      std::atomic<int> compare(1);
      etl::atomic<int> test(1);

      CHECK_EQUAL(compare.fetch_sub(2), test.fetch_sub(2));
    }

    //*************************************************************************
    TEST(test_atomic_operator_pointer_fetch_sub)
    {
      int data[] = {1, 2, 3, 4};

      std::atomic<int*> compare(&data[0]);
      etl::atomic<int*> test(&data[0]);

      CHECK_EQUAL(compare.fetch_add(ptrdiff_t(10)), test.fetch_add(ptrdiff_t(10)));
    }

    //*************************************************************************
    TEST(test_atomic_operator_fetch_and)
    {
      std::atomic<int> compare(int(0xFFFFFFFFUL));
      etl::atomic<int> test(int(0xFFFFFFFFUL));

      CHECK_EQUAL(compare.fetch_and(0x55AA55AAUL), test.fetch_and(0x55AA55AAUL));
    }

    //*************************************************************************
    TEST(test_atomic_operator_fetch_or)
    {
      std::atomic<int> compare(0x0000FFFFUL);
      etl::atomic<int> test(0x0000FFFFUL);

      CHECK_EQUAL(compare.fetch_or(0x55AA55AAUL), test.fetch_or(0x55AA55AAUL));
    }

    //*************************************************************************
    TEST(test_atomic_operator_fetch_xor)
    {
      std::atomic<int> compare(0x0000FFFFUL);
      etl::atomic<int> test(0x0000FFFFUL);

      CHECK_EQUAL(compare.fetch_xor(0x55AA55AAUL), test.fetch_xor(0x55AA55AAUL));
    }

    //*************************************************************************
    TEST(test_atomic_operator_fetch_max_when_new_value_is_greater)
    {
      etl::atomic<int> test(10);

      int old_value = test.fetch_max(20);

      CHECK_EQUAL(10, old_value);
      CHECK_EQUAL(20, test.load());
    }

    //*************************************************************************
    TEST(test_atomic_operator_fetch_max_when_new_value_is_less)
    {
      etl::atomic<int> test(30);

      int old_value = test.fetch_max(20);

      CHECK_EQUAL(30, old_value);
      CHECK_EQUAL(30, test.load());
    }

    //*************************************************************************
    TEST(test_atomic_operator_fetch_max_when_new_value_is_equal)
    {
      etl::atomic<int> test(20);

      int old_value = test.fetch_max(20);

      CHECK_EQUAL(20, old_value);
      CHECK_EQUAL(20, test.load());
    }

    //*************************************************************************
    TEST(test_atomic_operator_fetch_min_when_new_value_is_less)
    {
      etl::atomic<int> test(30);

      int old_value = test.fetch_min(20);

      CHECK_EQUAL(30, old_value);
      CHECK_EQUAL(20, test.load());
    }

    //*************************************************************************
    TEST(test_atomic_operator_fetch_min_when_new_value_is_greater)
    {
      etl::atomic<int> test(10);

      int old_value = test.fetch_min(20);

      CHECK_EQUAL(10, old_value);
      CHECK_EQUAL(10, test.load());
    }

    //*************************************************************************
    TEST(test_atomic_operator_fetch_min_when_new_value_is_equal)
    {
      etl::atomic<int> test(20);

      int old_value = test.fetch_min(20);

      CHECK_EQUAL(20, old_value);
      CHECK_EQUAL(20, test.load());
    }

    //*************************************************************************
    TEST(test_atomic_integer_exchange)
    {
      std::atomic<int> compare(1);
      etl::atomic<int> test(1);

      CHECK_EQUAL(compare.exchange(2), test.exchange(2));
    }

    //*************************************************************************
    TEST(test_atomic_enum_exchange)
    {
      std::atomic<Enum> compare(Enum::One);
      etl::atomic<Enum> test(Enum::One);

      CHECK_EQUAL(compare.exchange(Enum::Two), test.exchange(Enum::Two));
    }

    //*************************************************************************
    TEST(test_atomic_pointer_exchange)
    {
      int i;
      int j;

      std::atomic<int*> compare(&i);
      etl::atomic<int*> test(&i);

      CHECK_EQUAL(compare.exchange(&j), test.exchange(&j));
    }

    //*************************************************************************
    TEST(test_atomic_bool_exchange)
    {
      std::atomic<bool> compare(false);
      etl::atomic<bool> test(false);

      CHECK_EQUAL(compare.exchange(true), test.exchange(true));
    }

    //*************************************************************************
    TEST(test_atomic_compare_exchange_weak_fail)
    {
      std::atomic<int> compare;
      etl::atomic<int> test;

      int actual = 1;

      compare = actual;
      test    = actual;

      int compare_expected = 2;
      int test_expected    = 2;
      int desired          = 3;

      bool compare_result = compare.compare_exchange_weak(compare_expected, desired);
      bool test_result    = test.compare_exchange_weak(test_expected, desired);

      CHECK_EQUAL(compare_result, test_result);
      CHECK_EQUAL(compare_expected, test_expected);
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_compare_exchange_weak_pass)
    {
      std::atomic<int> compare;
      etl::atomic<int> test;

      int actual = 1;

      compare = actual;
      test    = actual;

      int compare_expected = actual;
      int test_expected    = actual;
      int desired          = 3;

      bool compare_result = compare.compare_exchange_weak(compare_expected, desired);
      bool test_result    = test.compare_exchange_weak(test_expected, desired);

      CHECK_EQUAL(compare_result, test_result);
      CHECK_EQUAL(compare_expected, test_expected);
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_compare_exchange_weak_pass_for_enum)
    {
      std::atomic<Enum> compare(Enum::Zero);
      etl::atomic<Enum> test(Enum::Zero);

      Enum actual = Enum::One;

      compare = actual;
      test    = actual;

      Enum compare_expected = actual;
      Enum test_expected    = actual;
      Enum desired          = Enum::Two;

      bool compare_result = compare.compare_exchange_weak(compare_expected, desired);
      bool test_result    = test.compare_exchange_weak(test_expected, desired);

      CHECK_EQUAL(compare_result, test_result);
      CHECK_EQUAL(compare_expected, test_expected);
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_compare_exchange_weak_pass_for_bool)
    {
      std::atomic<bool> compare;
      etl::atomic<bool> test;

      bool actual = false;

      compare = actual;
      test    = actual;

      bool compare_expected = actual;
      bool test_expected    = actual;
      bool desired          = true;

      bool compare_result = compare.compare_exchange_weak(compare_expected, desired);
      bool test_result    = test.compare_exchange_weak(test_expected, desired);

      CHECK_EQUAL(compare_result, test_result);
      CHECK_EQUAL(compare_expected, test_expected);
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_compare_exchange_strong_fail)
    {
      std::atomic<int> compare;
      etl::atomic<int> test;

      int actual = 1;

      compare = actual;
      test    = actual;

      int compare_expected = 2;
      int test_expected    = 2;
      int desired          = 3;

      bool compare_result = compare.compare_exchange_strong(compare_expected, desired);
      bool test_result    = test.compare_exchange_strong(test_expected, desired);

      CHECK_EQUAL(compare_result, test_result);
      CHECK_EQUAL(compare_expected, test_expected);
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_compare_exchange_strong_pass)
    {
      std::atomic<int> compare;
      etl::atomic<int> test;

      int actual = 1;

      compare = actual;
      test    = actual;

      int compare_expected = actual;
      int test_expected    = actual;
      int desired          = 3;

      bool compare_result = compare.compare_exchange_strong(compare_expected, desired);
      bool test_result    = test.compare_exchange_strong(test_expected, desired);

      CHECK_EQUAL(compare_result, test_result);
      CHECK_EQUAL(compare_expected, test_expected);
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_compare_exchange_strong_pass_for_enum)
    {
      std::atomic<Enum> compare(Enum::Zero);
      etl::atomic<Enum> test(Enum::Zero);

      Enum actual = Enum::One;

      compare = actual;
      test    = actual;

      Enum compare_expected = actual;
      Enum test_expected    = actual;
      Enum desired          = Enum::Two;

      bool compare_result = compare.compare_exchange_strong(compare_expected, desired);
      bool test_result    = test.compare_exchange_strong(test_expected, desired);

      CHECK_EQUAL(compare_result, test_result);
      CHECK_EQUAL(compare_expected, test_expected);
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_compare_exchange_strong_pass_for_bool)
    {
      std::atomic<bool> compare;
      etl::atomic<bool> test;

      bool actual = false;

      compare = actual;
      test    = actual;

      bool compare_expected = actual;
      bool test_expected    = actual;
      bool desired          = true;

      bool compare_result = compare.compare_exchange_strong(compare_expected, desired);
      bool test_result    = test.compare_exchange_strong(test_expected, desired);

      CHECK_EQUAL(compare_result, test_result);
      CHECK_EQUAL(compare_expected, test_expected);
      CHECK_EQUAL(compare.load(), test.load());
    }

    //*************************************************************************
    TEST(test_atomic_non_scalar_trivially_copyable_struct)
    {
      struct Data
      {
        int x;
        int y;

        bool operator==(const Data& other) const
        {
          return (x == other.x) && (y == other.y);
        }
      };

      // Default construction
      etl::atomic<Data> test;

      Data d1 = {1, 2};
      Data d2 = {3, 4};
      Data d3 = {5, 6};

      // Store and load
      test.store(d1);
      Data loaded = test.load();
      CHECK_EQUAL(d1.x, loaded.x);
      CHECK_EQUAL(d1.y, loaded.y);

      // Assignment operator
      test   = d2;
      loaded = test.load();
      CHECK_EQUAL(d2.x, loaded.x);
      CHECK_EQUAL(d2.y, loaded.y);

      // Conversion operator
      test.store(d1);
      Data converted = static_cast<Data>(test);
      CHECK_EQUAL(d1.x, converted.x);
      CHECK_EQUAL(d1.y, converted.y);

      // Exchange
      test.store(d1);
      Data old_val = test.exchange(d2);
      CHECK_EQUAL(d1.x, old_val.x);
      CHECK_EQUAL(d1.y, old_val.y);
      loaded = test.load();
      CHECK_EQUAL(d2.x, loaded.x);
      CHECK_EQUAL(d2.y, loaded.y);

      // Compare exchange weak - pass (expected matches)
      test.store(d1);
      Data expected = d1;
      bool result   = test.compare_exchange_weak(expected, d3);
      CHECK_TRUE(result);
      loaded = test.load();
      CHECK_EQUAL(d3.x, loaded.x);
      CHECK_EQUAL(d3.y, loaded.y);

      // Compare exchange weak - fail (expected does not match)
      test.store(d1);
      expected = d2;
      result   = test.compare_exchange_weak(expected, d3);
      CHECK_FALSE(result);
      loaded = test.load();
      CHECK_EQUAL(d1.x, loaded.x);
      CHECK_EQUAL(d1.y, loaded.y);

      // Compare exchange weak with two memory order args - pass
      test.store(d1);
      expected = d1;
      result   = test.compare_exchange_weak(expected, d2, etl::memory_order_seq_cst, etl::memory_order_seq_cst);
      CHECK_TRUE(result);
      loaded = test.load();
      CHECK_EQUAL(d2.x, loaded.x);
      CHECK_EQUAL(d2.y, loaded.y);

      // Compare exchange strong - pass (expected matches)
      test.store(d1);
      expected = d1;
      result   = test.compare_exchange_strong(expected, d3);
      CHECK_TRUE(result);
      loaded = test.load();
      CHECK_EQUAL(d3.x, loaded.x);
      CHECK_EQUAL(d3.y, loaded.y);

      // Compare exchange strong - fail (expected does not match)
      test.store(d1);
      expected = d2;
      result   = test.compare_exchange_strong(expected, d3);
      CHECK_FALSE(result);
      loaded = test.load();
      CHECK_EQUAL(d1.x, loaded.x);
      CHECK_EQUAL(d1.y, loaded.y);

      // Compare exchange strong with two memory order args - pass
      test.store(d1);
      expected = d1;
      result   = test.compare_exchange_strong(expected, d2, etl::memory_order_seq_cst, etl::memory_order_seq_cst);
      CHECK_TRUE(result);
      loaded = test.load();
      CHECK_EQUAL(d2.x, loaded.x);
      CHECK_EQUAL(d2.y, loaded.y);

      // Explicit memory order on store/load
      test.store(d3, etl::memory_order_release);
      loaded = test.load(etl::memory_order_acquire);
      CHECK_EQUAL(d3.x, loaded.x);
      CHECK_EQUAL(d3.y, loaded.y);

      // Exchange with explicit memory order
      test.store(d1);
      old_val = test.exchange(d2, etl::memory_order_acq_rel);
      CHECK_EQUAL(d1.x, old_val.x);
      CHECK_EQUAL(d1.y, old_val.y);
      loaded = test.load();
      CHECK_EQUAL(d2.x, loaded.x);
      CHECK_EQUAL(d2.y, loaded.y);

      // Value construction
      etl::atomic<Data> test2(d1);
      loaded = test2.load();
      CHECK_EQUAL(d1.x, loaded.x);
      CHECK_EQUAL(d1.y, loaded.y);
    }

    //*************************************************************************
#if REALTIME_TEST

  #if defined(ETL_TARGET_OS_WINDOWS) // Only Windows priority is currently
                                     // supported
    #define RAISE_THREAD_PRIORITY   SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_HIGHEST)
    #define FIX_PROCESSOR_AFFINITY1 SetThreadAffinityMask(GetCurrentThread(), 1)
    #define FIX_PROCESSOR_AFFINITY2 SetThreadAffinityMask(GetCurrentThread(), 2)
  #else
    #define RAISE_THREAD_PRIORITY
    #define FIX_PROCESSOR_AFFINITY1
    #define FIX_PROCESSOR_AFFINITY2
  #endif

    etl::atomic_int32_t atomic_value = 0U;
    etl::atomic<int>    start        = false;

    void thread1()
    {
      RAISE_THREAD_PRIORITY;
      FIX_PROCESSOR_AFFINITY1;

      while (!start.load());

      for (int i = 0; i < 10000000; ++i)
      {
        ++atomic_value;
      }
    }

    void thread2()
    {
      RAISE_THREAD_PRIORITY;
      FIX_PROCESSOR_AFFINITY2;

      while (!start.load());

      for (int i = 0; i < 10000000; ++i)
      {
        --atomic_value;
      }
    }

    TEST(test_atomic_multi_thread)
    {
      std::thread t1(thread1);
      std::thread t2(thread2);

      start.store(true);

      t1.join();
      t2.join();

      CHECK_EQUAL(0, atomic_value.load());
    }
#endif
  }
} // namespace