bit_reverse

eve::bit_reverse = functor<bit_reverse_t>

inlineconstexpr

Header file

#include <eve/module/core.hpp>

Callable Signatures

namespace eve
{
   // Regular overloads
   constexpr auto bit_reverse(unsigned_value auto x)                                   noexcept; // 1
   constexpr auto bit_reverse(unsigned_value auto x integral_scalar_value n)           noexcept; // 2
 
   // Lanes masking
   constexpr auto bit_reverse[conditional_expr auto c](/*any of the above overloads*/) noexcept; // 3
   constexpr auto bit_reverse[logical_value auto m](/*any of the above overloads*/)    noexcept; // 3
}

Parameters

• x: argument.
• n: n scalar delimiting the band to be reversed at both ends of x.
• c: Conditional expression masking the operation.
• m: Logical value masking the operation.

Return value

1. The values of the of the parameter are returned with bits in reversed order.
2. if n is present :
   • if n == 0 the call returns x
   • if 2*n is greater or equal to the size of the element type of x, the call is identical to reverse(x).
   • otherwise the first n bits and the last n bits of each element of x are swapped in reverse order and the central remaining bits are unchanged.
3. The operation is performed conditionnaly.

Example

// revision 1
#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 << "-> bit_reverse(wu0)                 = " << eve::bit_reverse(wu0) << "\n";
  std::cout << "-> bit_reverse(wu0, 3)              = " << eve::bit_reverse(wu0, 3) << "\n";
  std::cout << "-> bit_reverse[ignore_last(2)](wu0) = " << eve::bit_reverse[eve::ignore_last(2)](wu0) << "\n";
  std::cout << "-> bit_reverse[wu0 != 2u](wu0)      = " << eve::bit_reverse[wu0 != 2u](wu0) << "\n";
}