bit_select

eve::bit_select = {}

inlineconstexpr

selects bits from a mask and two entries.

Defined in Header

#include <eve/module/core.hpp>

Callable Signatures

namespace eve
{
  template< value T, value U > bit_select)( T m, U x, U y )
  requires compatible< T,U> noexcept;
}

Parameters

• m: mask value

• y, z: selection values

  • x : argument.

  Return value

  • In a short way (omitting casting details to bring all bit sizes of the parameters equal), it means that the result is composed of the bits of x for which the corresponding bit of m is set and the bits of y for which the corresponding bit of m is unset.
  • If T or U is an simd value, the type of the result has the element type of T and the maximum of the cardinals of M and T, otherwise it is T. The value of the selected bits is returned.

Example

#include <eve/wide.hpp>
#include <iostream>
#include <iomanip>
 
using wide_t = eve::wide<std::uint16_t, eve::fixed<4>>;
 
int main()
{
 
  wide_t pi = {2, -3, 0,  1 << 10};
  wide_t qi = {3, -2, 4,  2 };
  wide_t mi = {0, -1, 1, ~0u << 8};
 
  std::cout << "---- simd" << '\n'
            << " <- mi                                = " << mi << '\n'
            << " <- pi                                = " << pi << '\n'
            << " <- qi                                = " << qi << '\n'
            << " -> bit_select(mi, pi, qi)            = " << eve::bit_select(mi, pi, qi) << '\n';
 
  std::cout << "---- scalar" << std::setprecision(10) << '\n'
            << " -> bit_select(32767, 1, 32768 )      = " << eve::bit_select(32767, 1, 32768) << '\n';
  return 0;
}