TheRock/math-libs/libhipcxx/.upstream-tests/test/support/hexfloat.h

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// Define a hexfloat literal emulator since we can't depend on being able to
//   for hexfloat literals

// 0x10.F5p-10 == hexfloat<double>(0x10, 0xF5, -10)

#ifndef HEXFLOAT_H
#define HEXFLOAT_H

#include <climits>
#include <cmath>

template <class T>
class hexfloat
{
  T value_;

  static int CountLeadingZeros(unsigned long long n)
  {
    const std::size_t Digits        = sizeof(unsigned long long) * CHAR_BIT;
    const unsigned long long TopBit = 1ull << (Digits - 1);
    if (n == 0)
    {
      return Digits;
    }
    int LeadingZeros = 0;
    while ((n & TopBit) == 0)
    {
      ++LeadingZeros;
      n <<= 1;
    }
    return LeadingZeros;
  }

public:
  hexfloat(long long m1, unsigned long long m0, int exp)
  {
    const std::size_t Digits = sizeof(unsigned long long) * CHAR_BIT;
    int s                    = m1 < 0 ? -1 : 1;
    int exp2                 = -static_cast<int>(Digits - CountLeadingZeros(m0) / 4 * 4);
    value_                   = std::ldexp(m1 + s * std::ldexp(T(m0), exp2), exp);
  }

  operator T() const
  {
    return value_;
  }
};

#endif