eve::top_bits< Logical > Struct Template Reference

The cheapest to get bitset for simd logical. More...

Detailed Description

template<logical_simd_value Logical>
struct eve::top_bits< Logical >

One value in top bits can be represented by multiple bits (bits_per_element member constant).

NOTE: this is a generalization of movemask instructions from x86

Typical usage: created with CTAD: top_bits{logical}.

Template Parameters

Logical

simd value.

Public Types
using	logical_type = Logical
	The associated wide logical.
using	scalar_type = typename as_arithmetic_t< logical_type >::value_type
	For top_bits<logical<wide<T, N>>> this is T;.
using	abi_type = typename as_arithmetic_t< logical_type >::abi_type
	ABI of the underlying simd value.
using	half_logical = logical< wide< scalar_type, eve::fixed< half_size > > >
	logical of half size (or 1 if size is 1)
using	storage_type = decltype(top_bits::storage_type_impl())
	type of the underlying storage

Public Member Functions
constexpr void	set (std::ptrdiff_t i, bool x)
	setter

Static Public Attributes
static constexpr std::ptrdiff_t	static_size = logical_type::size()
	logical_type::size();
static constexpr bool	is_aggregated
	is stored as an array of 2 halves
static constexpr std::ptrdiff_t	bits_per_element = bits_per_element_impl()
	how many bits do we store per element
static constexpr std::ptrdiff_t	static_bits_size = static_size * bits_per_element
	how many bits are used
static constexpr bool	is_cheap = is_cheap_impl()
	is it considered a cheap operation (~1 instruction) to get top_bits from a logical.