countl_zero

eve::countl_zero = functor<countl_zero_t>

inlineconstexpr

Header file

#include <eve/module/core.hpp>

Callable Signatures

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

Parameters

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

Return value

1. The value of the number of consecutive 0 ("zero") bits in the value of x, starting from the most significant bit ("left"), with same type as x is returned.
2. The operation is performed conditionnaly.

External references

• C++ standard reference

Example

// revision 0
#include <eve/module/core.hpp>
#include <iostream>
 
int main()
{
  eve::wide wu0{0u, 1u, 2u, 3u, 4u, 5u, 6u, 7u};
 
  std::cout << "<- wu0                              = " << wu0 << "\n";
                                                    
  std::cout << "-> countl_zero(wu0)                 = " << eve::countl_zero(wu0) << "\n";
  std::cout << "-> countl_zero[ignore_last(2)](wu0) = " << eve::countl_zero[eve::ignore_last(2)](wu0) << "\n";
  std::cout << "-> countl_zero[wu0 != 0](wu0)       = " << eve::countl_zero[wu0 != 0](wu0) << "\n";
}