Traits.hpp

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/* Copyright 2022 Sergei Bastrakov, Bernhard Manfred Gruber
 * SPDX-License-Identifier: MPL-2.0
 */
 
#pragma once
 
#include "alpaka/core/Common.hpp"
#include "alpaka/core/Concepts.hpp"
 
#include <cstdint>
#include <type_traits>
 
namespace alpaka
{
    struct ConceptIntrinsic
    {
    };
 
    //! The intrinsics traits.
    namespace trait
    {
        //! The popcount trait.
        template<typename TWarp, typename TSfinae = void>
        struct Popcount;
 
        //! The ffs trait.
        template<typename TWarp, typename TSfinae = void>
        struct Ffs;
    } // namespace trait
 
    //! Returns the number of 1 bits in the given 32-bit value.
    //!
    //! \tparam TIntrinsic The intrinsic implementation type.
    //! \param intrinsic The intrinsic implementation.
    //! \param value The input value.
    ALPAKA_NO_HOST_ACC_WARNING
    template<typename TIntrinsic>
    ALPAKA_FN_ACC auto popcount(TIntrinsic const& intrinsic, std::uint32_t value) -> std::int32_t
    {
        using ImplementationBase = concepts::ImplementationBase<ConceptIntrinsic, TIntrinsic>;
        return trait::Popcount<ImplementationBase>::popcount(intrinsic, value);
    }
 
    //! Returns the number of 1 bits in the given 64-bit value.
    //!
    //! \tparam TIntrinsic The intrinsic implementation type.
    //! \param intrinsic The intrinsic implementation.
    //! \param value The input value.
    ALPAKA_NO_HOST_ACC_WARNING
    template<typename TIntrinsic>
    ALPAKA_FN_ACC auto popcount(TIntrinsic const& intrinsic, std::uint64_t value) -> std::int32_t
    {
        using ImplementationBase = concepts::ImplementationBase<ConceptIntrinsic, TIntrinsic>;
        return trait::Popcount<ImplementationBase>::popcount(intrinsic, value);
    }
 
    //! Returns the 1-based position of the least significant bit set to 1
    //! in the given 32-bit value. Returns 0 for input value 0.
    //!
    //! \tparam TIntrinsic The intrinsic implementation type.
    //! \param intrinsic The intrinsic implementation.
    //! \param value The input value.
    ALPAKA_NO_HOST_ACC_WARNING
    template<typename TIntrinsic>
    ALPAKA_FN_ACC auto ffs(TIntrinsic const& intrinsic, std::int32_t value) -> std::int32_t
    {
        using ImplementationBase = concepts::ImplementationBase<ConceptIntrinsic, TIntrinsic>;
        return trait::Ffs<ImplementationBase>::ffs(intrinsic, value);
    }
 
    //! Returns the 1-based position of the least significant bit set to 1
    //! in the given 64-bit value. Returns 0 for input value 0.
    //!
    //! \tparam TIntrinsic The intrinsic implementation type.
    //! \param intrinsic The intrinsic implementation.
    //! \param value The input value.
    ALPAKA_NO_HOST_ACC_WARNING
    template<typename TIntrinsic>
    ALPAKA_FN_ACC auto ffs(TIntrinsic const& intrinsic, std::int64_t value) -> std::int32_t
    {
        using ImplementationBase = concepts::ImplementationBase<ConceptIntrinsic, TIntrinsic>;
        return trait::Ffs<ImplementationBase>::ffs(intrinsic, value);
    }
} // namespace alpaka