mantissa

eve::mantissa = functor<mantissa_t>

inlineconstexpr

Header file

#include <eve/module/core.hpp>

Callable Signatures

namespace eve
{
   // Regular overload
   constexpr auto mantissa(floating_value auto x)                          noexcept; // 1
 
   // Lanes masking
   constexpr auto mantissa[conditional_expr auto c](floating_value auto x) noexcept; // 2
   constexpr auto mantissa[logical_value auto m](floating_value auto x)    noexcept; // 2
 
   // Semantic options
   constexpr auto mantissa[raw](floating_value auto x)                     noexcept; // 3
}

Parameters

• x: real argument.
• c: Conditional expression masking the operation.
• m: Logical value masking the operation.

Return value

1. The value of the IEEE mantissa is returned. In particular:
   • nan returns nan
   • \(\pm\infty\) returns \(\pm\1\).
   • zero returns zero
2. The operation is performed conditionnaly.
3. The results for zero and nan are unspecified.

Note

The exponent \(e\) and mantissa \(m\) of a floating point entry \(x\) are related by \(x = m\times 2^e\), with \(|m| \in \{0, nan\} \cup [1, 2[\).

Example

// revision 0
#include <eve/module/core.hpp>
#include <iostream>
 
int main()
{
  eve::wide wf0{0.0, 1.0, 2.0, 3.0, -1.0, -2.0, -3.0, -4.0};
 
  std::cout << "<- wf0                           = " << wf0 << "\n";
                                                 
  std::cout << "-> mantissa(wf0)                 = " << eve::mantissa(wf0) << "\n";
  std::cout << "-> mantissa[ignore_last(2)](wf0) = " << eve::mantissa[eve::ignore_last(2)](wf0) << "\n";
  std::cout << "-> mantissa[wf0 != 0](wf0)       = " << eve::mantissa[wf0 != 0](wf0) << "\n";
  std::cout << "-> mantissa[raw](wf0)            = " << eve::mantissa[eve::raw](wf0) << "\n";
}