Function signbit

cpp/src/arrow/util/float16.h:77–77

\brief Return true if the value is negative (sign bit is set)

  /// \brief Return true if the value is negative (sign bit is set)
  constexpr bool signbit() const { return (bits_ & 0x8000) != 0; }

  /// \brief Return true if the value is NaN
  constexpr bool is_nan() const { return (bits_ & 0x7fff) > 0x7c00; }