firstbitset

auto eve::firstbitset = functor<firstbitset_t>

inlineconstexpr

Header file

#include <eve/module/core.hpp>

Callable Signatures

namespace eve
{
   // Regular overload
   constexpr auto firstbitset(integral_value auto x)                          noexcept; // 1
 
   // Lanes masking
   constexpr auto firstbitset[conditional_expr auto c](integral_value auto x) noexcept; // 2
   constexpr auto firstbitset[logical_value auto m](integral_value auto x)    noexcept; // 2
}

Parameters

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

Return value

1. Computes elementwise the bit pattern in which the only bit set (if it exists) is the first bit set (beginning with the least significant bit) in the input.
2. The operation is performed conditionnaly.

Example

// revision 0
#include <eve/module/core.hpp>
#include <iostream>
 
int main()
{
  eve::wide wi0{0, 1, 2, 3, -1, -2, -3, -4};
 
  std::cout << "<- wi0                              = " << wi0 << "\n";
                                                    
  std::cout << "-> firstbitset(wi0)                 = " << eve::firstbitset(wi0) << "\n";
  std::cout << "-> firstbitset[ignore_last(2)](wi0) = " << eve::firstbitset[eve::ignore_last(2)](wi0) << "\n";
  std::cout << "-> firstbitset[wi0 != 0](wi0)       = " << eve::firstbitset[wi0 != 0](wi0) << "\n";
}