prev

eve::prev = functor<prev_t>

inlineconstexpr

Defined in Header

#include <eve/module/core.hpp>

Callable Signatures

namespace eve
{
   // Regular overloads
   constexpr auto prev(value auto x)                                              noexcept; // 1
   constexpr auto prev(value auto x, integral_value auto n)                       noexcept; // 2
 
   // Lanes masking
   constexpr auto prev[conditional_expr auto c](/* any of the above overloads */) noexcept; // 3
   constexpr auto prev[logical_value auto m](/* any of the above overloads */)    noexcept; // 3
 
   // Exclusive Semantic options - Only one of those can be set at once
   constexpr auto prev[pedantic](/* any of the above overloads */)                noexcept; // 4
   constexpr auto prev[saturated ](/* any of the above overloads */)              noexcept; // 5
   constexpr auto prev[raw](value auto x)                                         noexcept; // 6
}

Parameters

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

Return value

1. the greatest representable value less than x is returned.
2. the nth representable value less than x is returned. If n is zero returns x.
3. The operation is performed conditionnaly
4. if x is floating zero and mzero are considered distinct.
5. ensures that the input is never less than the result of the call.
6. works only if inputs are normal numbers (this excludes floating zeroes, denormals or not finite). the option has no influence on the two parameters calls

If n is zero returns x.

Example

// revision 0
#include <eve/module/core.hpp>
#include <iostream>
 
int main()
{
  eve::wide wf0 = {-0.0f, 2.0f, eve::eps(eve::as<float>()), 0.0f, 30.0f,eve::mindenormal(eve::as<float>()),
                   eve::minf(eve::as<float>()), eve::nan(eve::as<float>())};
  eve::wide wi0 = {-1, 2, -3, -4,  -32765, -32766, -32767, -32768 };
  eve::wide wu0 = {0u, 1u, 2u, 3u, 4u, 5u, 6u, 7u};
 
  std::cout << "<- wf0                       = " << wf0 << "\n";
  std::cout << "<- wi0                       = " << wi0 << "\n";
  std::cout << "<- wu0                       = " << wu0 << "\n";
 
  std::cout << "-> prev(wf0)                 = " << eve::prev(wf0) << "\n";
  std::cout << "-> prev(wf0, wi1)            = " << eve::prev(wf0, wu0) << "\n";
  std::cout << "-> prev[ignore_last(2)](wf0) = " << eve::prev[eve::ignore_last(2)](wf0) << "\n";
  std::cout << "-> prev[wf0 != 0](wf0)       = " << eve::prev[wf0 != 0](wf0) << "\n";
  std::cout << "-> prev[pedantic](wf0)       = " << eve::prev[eve::pedantic](wf0) << "\n";
  std::cout << "-> prev[saturated ](wi0)     = " << eve::prev[eve::saturated ](wi0) << "\n";
  std::cout << "-> prev(wu0)                 = " << eve::prev(wu0) << "\n";
  std::cout << "-> prev(wi0)                 = " << eve::prev(wi0) << "\n";
  std::cout << "-> prev(wi0, wu0)            = " << eve::prev(wi0, wu0) << "\n";
}