example001_roots_sqrt.cpp

///////////////////////////////////////////////////////////////////
//  Copyright Christopher Kormanyos 2020 - 2022.                 //
//  Distributed under the Boost Software License,                //
//  Version 1.0. (See accompanying file LICENSE_1_0.txt          //
//  or copy at http://www.boost.org/LICENSE_1_0.txt)             //
///////////////////////////////////////////////////////////////////

#include <cmath>
#include <cstdint>

#include <math/softfloat/soft_double.h>
#include <math/softfloat/soft_double_examples.h>

static_assert(sizeof(double) == 8U, // NOLINT(cppcoreguidelines-avoid-magic-numbers,readability-magic-numbers)
              "Error: This example requires 8 byte built-in double for verification");

auto math::softfloat::example001_roots_sqrt() -> bool
{
  // Use a cached value for pi.
  constexpr float64_t my_pi = float64_t::my_value_pi();

  // Compute soft_double sqrt(pi).
  #if (defined(_MSC_VER) && (_MSC_VER < 1920))
  #pragma warning(push)
  #pragma warning(disable : 4307)
  #endif
  constexpr float64_t s = sqrt(my_pi);
  #if (defined(_MSC_VER) && (_MSC_VER < 1920))
  #pragma warning(pop)
  #endif

  using std::sqrt;

  // Compare with native double sqrt(pi).
  const auto result_root_is_ok =
    (s.crepresentation() == float64_t(sqrt(3.1415926535897932384626433832795028841972)).crepresentation());

  constexpr auto result_root_as_constexpr_is_ok =
    (s.crepresentation() == static_cast<typename float64_t::representation_type>(UINT64_C(0x3FFC5BF891B4EF6A)));

  #if (defined(SOFT_DOUBLE_CONSTEXPR_IS_COMPILE_TIME_CONST) && (SOFT_DOUBLE_CONSTEXPR_IS_COMPILE_TIME_CONST != 0))
  static_assert(result_root_as_constexpr_is_ok, "Error: example001_roots_sqrt not OK!");
  #endif

  const auto result_is_ok = (result_root_is_ok && result_root_as_constexpr_is_ok);

  return result_is_ok;
}

// Enable this if you would like to activate this main() as a standalone example.
#if 0

#include <iomanip>
#include <iostream>

int main()
{
  const bool result_is_ok = math::softfloat::example001_roots_sqrt();

  std::cout << "result_is_ok: " << std::boolalpha << result_is_ok << std::endl;
}

#endif