sign_manipulation.h

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#pragma once
 
 
// === DECLARATIONS ===================================================================================================
 
#include "mjolnir/core/x86/definitions.h"
 
 
namespace mjolnir::x86
{
 
 
template <FloatVectorRegister T_RegisterType>
[[nodiscard]] inline auto abs(T_RegisterType src) noexcept -> T_RegisterType;
 
 
template <bool t_all_mag_positive = false, FloatVectorRegister T_RegisterType>
[[nodiscard]] inline auto copy_sign(T_RegisterType src_magnitude, T_RegisterType src_sign) noexcept -> T_RegisterType;
 
 
template <FloatVectorRegister T_RegisterType>
[[nodiscard]] inline auto negate_all(T_RegisterType src) noexcept -> T_RegisterType;
 
 
template <bool... t_neg, FloatVectorRegister T_RegisterType>
[[nodiscard]] inline auto negate_selected(T_RegisterType src) noexcept -> T_RegisterType;
 
 
} // namespace mjolnir::x86
 
 
// === DEFINITIONS ====================================================================================================
 
#include "mjolnir/core/x86/comparison.h"
#include "mjolnir/core/x86/intrinsics.h"
 
#include <cassert>
 
 
namespace mjolnir::x86
{
// --------------------------------------------------------------------------------------------------------------------
 
template <FloatVectorRegister T_RegisterType>
[[nodiscard]] inline auto abs(T_RegisterType src) noexcept -> T_RegisterType
{
    using EType     = ElementType<T_RegisterType>;
    const auto mask = mm_set1<T_RegisterType>(static_cast<EType>(-0.0));
 
    return mm_andnot(mask, src);
}
 
 
// --------------------------------------------------------------------------------------------------------------------
 
template <bool t_all_mag_positive, FloatVectorRegister T_RegisterType>
[[nodiscard]] inline auto copy_sign(T_RegisterType src_magnitude, T_RegisterType src_sign) noexcept -> T_RegisterType
{
    using EType     = ElementType<T_RegisterType>;
    const auto mask = mm_set1<T_RegisterType>(static_cast<EType>(-0.0));
 
    T_RegisterType sign = mm_and(src_sign, mask);
 
    if constexpr (! t_all_mag_positive)
        src_magnitude = mm_andnot(mask, src_magnitude);
 
    assert(is_memory_zero(mm_and(src_magnitude, mask)) && "Signed bit of one or more values set."); // NOLINT
    return mm_or(sign, src_magnitude);
}
 
 
// --------------------------------------------------------------------------------------------------------------------
 
 
template <FloatVectorRegister T_RegisterType>
[[nodiscard]] inline auto negate_all(T_RegisterType src) noexcept -> T_RegisterType
{
    constexpr UST n_e = num_elements<T_RegisterType>;
 
    if constexpr (n_e == 2)
        return negate_selected<1, 1>(src);
    else if constexpr (n_e == 4)
        return negate_selected<1, 1, 1, 1>(src);
    else
        return negate_selected<1, 1, 1, 1, 1, 1, 1, 1>(src);
}
 
 
// --------------------------------------------------------------------------------------------------------------------
 
 
template <bool... t_neg, FloatVectorRegister T_RegisterType>
[[nodiscard]] inline auto negate_selected(T_RegisterType src) noexcept -> T_RegisterType
{
    using EType       = ElementType<T_RegisterType>;
    constexpr UST n_e = num_elements<T_RegisterType>;
 
    static_assert(sizeof...(t_neg) == n_e,
                  "Number of boolean template parameters must be 0 or equal to the number of register elements");
 
    constexpr auto get_mask = [](bool a) constexpr->EType
    {
        if (a)
            return static_cast<EType>(-0.);
        return static_cast<EType>(0.);
    };
    auto mask = mm_setr<T_RegisterType>(get_mask(t_neg)...);
 
    return mm_xor(src, mask);
}
 
} // namespace mjolnir::x86