DirectXMath/Extensions/DirectXMathAVX.h

//-------------------------------------------------------------------------------------
// DirectXMathAVX.h -- AVX (version 1) extensions for SIMD C++ Math library
//
// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License.
//
// http://go.microsoft.com/fwlink/?LinkID=615560
//-------------------------------------------------------------------------------------

#ifdef _MSC_VER
#pragma once
#endif

#ifdef _M_ARM
#error AVX not supported on ARM platform
#endif

#if defined(_MSC_VER) && (_MSC_VER < 1600)
#error AVX intrinsics requires Visual C++ 2010 Service Pack 1 or later.
#endif

#pragma warning(push)
#pragma warning(disable : 4987)
#include <intrin.h>
#pragma warning(pop)

#include <immintrin.h>

#include <DirectXMath.h>

namespace DirectX
{

namespace AVX
{

inline bool XMVerifyAVXSupport()
{
    // Should return true for AMD Bulldozer, Intel "Sandy Bridge", and Intel "Ivy Bridge" or later processors
    // with OS support for AVX (Windows 7 Service Pack 1, Windows Server 2008 R2 Service Pack 1, Windows 8, Windows Server 2012)

    // See http://msdn.microsoft.com/en-us/library/hskdteyh.aspx
    int CPUInfo[4] = {-1};
    __cpuid( CPUInfo, 0 );

    if ( CPUInfo[0] < 1  )
        return false;

    __cpuid(CPUInfo, 1 );

    // We check for AVX, OSXSAVE, SSSE4.1, and SSE3
    return ( (CPUInfo[2] & 0x18080001) == 0x18080001 );
}


//-------------------------------------------------------------------------------------
// Vector
//-------------------------------------------------------------------------------------

inline XMVECTOR XM_CALLCONV XMVectorReplicatePtr( _In_  const float *pValue )
{
    return _mm_broadcast_ss( pValue );
}

inline XMVECTOR XM_CALLCONV XMVectorSplatX( FXMVECTOR V )
{
    return _mm_permute_ps( V, _MM_SHUFFLE(0, 0, 0, 0) );
}

inline XMVECTOR XM_CALLCONV XMVectorSplatY( FXMVECTOR V )
{
    return _mm_permute_ps( V, _MM_SHUFFLE(1, 1, 1, 1) );
}

inline XMVECTOR XM_CALLCONV XMVectorSplatZ( FXMVECTOR V )
{
    return _mm_permute_ps( V, _MM_SHUFFLE(2, 2, 2, 2) );
}

inline XMVECTOR XM_CALLCONV XMVectorSplatW( FXMVECTOR V )
{
    return _mm_permute_ps( V, _MM_SHUFFLE(3, 3, 3, 3) );
}

inline XMVECTOR XM_CALLCONV XMVectorSwizzle( FXMVECTOR V, uint32_t E0, uint32_t E1, uint32_t E2, uint32_t E3 )
{
    assert( (E0 < 4) && (E1 < 4) && (E2 < 4) && (E3 < 4) );
    _Analysis_assume_( (E0 < 4) && (E1 < 4) && (E2 < 4) && (E3 < 4) );

    unsigned int elem[4] = { E0, E1, E2, E3 };
    __m128i vControl = _mm_loadu_si128( reinterpret_cast<const __m128i *>(&elem[0]) );
    return _mm_permutevar_ps( V, vControl );
}

inline XMVECTOR XM_CALLCONV XMVectorPermute( FXMVECTOR V1, FXMVECTOR V2, uint32_t PermuteX, uint32_t PermuteY, uint32_t PermuteZ, uint32_t PermuteW )
{
    assert( PermuteX <= 7 && PermuteY <= 7 && PermuteZ <= 7 && PermuteW <= 7 );
    _Analysis_assume_( PermuteX <= 7 && PermuteY <= 7 && PermuteZ <= 7 && PermuteW <= 7 );

    static const XMVECTORU32 three = { 3, 3, 3, 3 };

    _declspec(align(16)) unsigned int elem[4] = { PermuteX, PermuteY, PermuteZ, PermuteW };
    __m128i vControl = _mm_load_si128( reinterpret_cast<const __m128i *>(&elem[0]) );
    
    __m128i vSelect = _mm_cmpgt_epi32( vControl, three );
    vControl = _mm_castps_si128( _mm_and_ps( _mm_castsi128_ps( vControl ), three ) );

    __m128 shuffled1 = _mm_permutevar_ps( V1, vControl );
    __m128 shuffled2 = _mm_permutevar_ps( V2, vControl );

    __m128 masked1 = _mm_andnot_ps( _mm_castsi128_ps( vSelect ), shuffled1 );
    __m128 masked2 = _mm_and_ps( _mm_castsi128_ps( vSelect ), shuffled2 );

    return _mm_or_ps( masked1, masked2 );
}

inline XMVECTOR XM_CALLCONV XMVectorShiftLeft(FXMVECTOR V1, FXMVECTOR V2, uint32_t Elements)
{
    assert( Elements < 4 );
    _Analysis_assume_( Elements < 4 );
    return AVX::XMVectorPermute(V1, V2, Elements, ((Elements) + 1), ((Elements) + 2), ((Elements) + 3));
}

inline XMVECTOR XM_CALLCONV XMVectorRotateLeft(FXMVECTOR V, uint32_t Elements)
{
    assert( Elements < 4 );
    _Analysis_assume_( Elements < 4 );
    return AVX::XMVectorSwizzle( V, Elements & 3, (Elements + 1) & 3, (Elements + 2) & 3, (Elements + 3) & 3 );
}

inline XMVECTOR XM_CALLCONV XMVectorRotateRight(FXMVECTOR V, uint32_t Elements)
{
    assert( Elements < 4 );
    _Analysis_assume_( Elements < 4 );
    return AVX::XMVectorSwizzle( V, (4 - (Elements)) & 3, (5 - (Elements)) & 3, (6 - (Elements)) & 3, (7 - (Elements)) & 3 );
}


//-------------------------------------------------------------------------------------
// Permute Templates
//-------------------------------------------------------------------------------------

namespace Internal
{
    // Slow path fallback for permutes that do not map to a single SSE opcode.
    template<uint32_t Shuffle, bool WhichX, bool WhichY, bool WhichZ, bool WhichW> struct PermuteHelper
    {
        static XMVECTOR XM_CALLCONV Permute(FXMVECTOR v1, FXMVECTOR v2)
        {
            static const XMVECTORU32 selectMask =
            {
                WhichX ? 0xFFFFFFFF : 0,
                WhichY ? 0xFFFFFFFF : 0,
                WhichZ ? 0xFFFFFFFF : 0,
                WhichW ? 0xFFFFFFFF : 0,
            };

            XMVECTOR shuffled1 = _mm_permute_ps(v1, Shuffle);
            XMVECTOR shuffled2 = _mm_permute_ps(v2, Shuffle);

            XMVECTOR masked1 = _mm_andnot_ps(selectMask, shuffled1);
            XMVECTOR masked2 = _mm_and_ps(selectMask, shuffled2);

            return _mm_or_ps(masked1, masked2);
        }
    };

    // Fast path for permutes that only read from the first vector.
    template<uint32_t Shuffle> struct PermuteHelper<Shuffle, false, false, false, false>
    {
        static XMVECTOR XM_CALLCONV Permute(FXMVECTOR v1, FXMVECTOR v2) { (v2); return _mm_permute_ps(v1, Shuffle); }
    };

    // Fast path for permutes that only read from the second vector.
    template<uint32_t Shuffle> struct PermuteHelper<Shuffle, true, true, true, true>
    {
        static XMVECTOR XM_CALLCONV Permute(FXMVECTOR v1, FXMVECTOR v2){ (v1); return _mm_permute_ps(v2, Shuffle); }
    };

    // Fast path for permutes that read XY from the first vector, ZW from the second.
    template<uint32_t Shuffle> struct PermuteHelper<Shuffle, false, false, true, true>
    {
        static XMVECTOR XM_CALLCONV Permute(FXMVECTOR v1, FXMVECTOR v2) { return _mm_shuffle_ps(v1, v2, Shuffle); }
    };

    // Fast path for permutes that read XY from the second vector, ZW from the first.
    template<uint32_t Shuffle> struct PermuteHelper<Shuffle, true, true, false, false>
    {
        static XMVECTOR XM_CALLCONV Permute(FXMVECTOR v1, FXMVECTOR v2) { return _mm_shuffle_ps(v2, v1, Shuffle); }
    };
};

// General permute template
template<uint32_t PermuteX, uint32_t PermuteY, uint32_t PermuteZ, uint32_t PermuteW>
    inline XMVECTOR XM_CALLCONV XMVectorPermute(FXMVECTOR V1, FXMVECTOR V2)
{
    static_assert(PermuteX <= 7, "PermuteX template parameter out of range");
    static_assert(PermuteY <= 7, "PermuteY template parameter out of range");
    static_assert(PermuteZ <= 7, "PermuteZ template parameter out of range");
    static_assert(PermuteW <= 7, "PermuteW template parameter out of range");

    const uint32_t Shuffle = _MM_SHUFFLE(PermuteW & 3, PermuteZ & 3, PermuteY & 3, PermuteX & 3);

    const bool WhichX = PermuteX > 3;
    const bool WhichY = PermuteY > 3;
    const bool WhichZ = PermuteZ > 3;
    const bool WhichW = PermuteW > 3;

    return AVX::Internal::PermuteHelper<Shuffle, WhichX, WhichY, WhichZ, WhichW>::Permute(V1, V2);
}

// Special-case permute templates
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<0,1,2,3>(FXMVECTOR V1, FXMVECTOR V2) { (V2); return V1; }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<4,5,6,7>(FXMVECTOR V1, FXMVECTOR V2) { (V1); return V2; }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<4,1,2,3>(FXMVECTOR V1, FXMVECTOR V2) { return _mm_blend_ps(V1,V2,0x1); }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<0,5,2,3>(FXMVECTOR V1, FXMVECTOR V2) { return _mm_blend_ps(V1,V2,0x2); }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<4,5,2,3>(FXMVECTOR V1, FXMVECTOR V2) { return _mm_blend_ps(V1,V2,0x3); }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<0,1,6,3>(FXMVECTOR V1, FXMVECTOR V2) { return _mm_blend_ps(V1,V2,0x4); }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<4,1,6,3>(FXMVECTOR V1, FXMVECTOR V2) { return _mm_blend_ps(V1,V2,0x5); }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<0,5,6,3>(FXMVECTOR V1, FXMVECTOR V2) { return _mm_blend_ps(V1,V2,0x6); }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<4,5,6,3>(FXMVECTOR V1, FXMVECTOR V2) { return _mm_blend_ps(V1,V2,0x7); }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<0,1,2,7>(FXMVECTOR V1, FXMVECTOR V2) { return _mm_blend_ps(V1,V2,0x8); }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<4,1,2,7>(FXMVECTOR V1, FXMVECTOR V2) { return _mm_blend_ps(V1,V2,0x9); }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<0,5,2,7>(FXMVECTOR V1, FXMVECTOR V2) { return _mm_blend_ps(V1,V2,0xA); }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<4,5,2,7>(FXMVECTOR V1, FXMVECTOR V2) { return _mm_blend_ps(V1,V2,0xB); }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<0,1,6,7>(FXMVECTOR V1, FXMVECTOR V2) { return _mm_blend_ps(V1,V2,0xC); }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<4,1,6,7>(FXMVECTOR V1, FXMVECTOR V2) { return _mm_blend_ps(V1,V2,0xD); }
template<> inline XMVECTOR XM_CALLCONV XMVectorPermute<0,5,6,7>(FXMVECTOR V1, FXMVECTOR V2) { return _mm_blend_ps(V1,V2,0xE); }


//-------------------------------------------------------------------------------------
// Swizzle Templates
//-------------------------------------------------------------------------------------

// General swizzle template
template<uint32_t SwizzleX, uint32_t SwizzleY, uint32_t SwizzleZ, uint32_t SwizzleW>
    inline XMVECTOR XM_CALLCONV XMVectorSwizzle(FXMVECTOR V)
{
    static_assert(SwizzleX <= 3, "SwizzleX template parameter out of range");
    static_assert(SwizzleY <= 3, "SwizzleY template parameter out of range");
    static_assert(SwizzleZ <= 3, "SwizzleZ template parameter out of range");
    static_assert(SwizzleW <= 3, "SwizzleW template parameter out of range");

    return _mm_permute_ps( V, _MM_SHUFFLE( SwizzleW, SwizzleZ, SwizzleY, SwizzleX ) );
}

// Specialized swizzles
template<> inline XMVECTOR XM_CALLCONV XMVectorSwizzle<0,1,2,3>(FXMVECTOR V) { return V; }
template<> inline XMVECTOR XM_CALLCONV XMVectorSwizzle<0,0,2,2>(FXMVECTOR V) { return _mm_moveldup_ps(V); }
template<> inline XMVECTOR XM_CALLCONV XMVectorSwizzle<1,1,3,3>(FXMVECTOR V) { return _mm_movehdup_ps(V); }


//-------------------------------------------------------------------------------------
// Other Templates
//-------------------------------------------------------------------------------------

template<uint32_t Elements>
    inline XMVECTOR XM_CALLCONV XMVectorShiftLeft(FXMVECTOR V1, FXMVECTOR V2)
{
    static_assert( Elements < 4, "Elements template parameter out of range" );
    return AVX::XMVectorPermute<Elements, (Elements + 1), (Elements + 2), (Elements + 3)>(V1, V2);
}

template<uint32_t Elements>
    inline XMVECTOR XM_CALLCONV XMVectorRotateLeft(FXMVECTOR V)
{
    static_assert( Elements < 4, "Elements template parameter out of range" );
    return AVX::XMVectorSwizzle<Elements & 3, (Elements + 1) & 3, (Elements + 2) & 3, (Elements + 3) & 3>(V);
}

template<uint32_t Elements>
    inline XMVECTOR XM_CALLCONV XMVectorRotateRight(FXMVECTOR V)
{
    static_assert( Elements < 4, "Elements template parameter out of range" );
    return AVX::XMVectorSwizzle<(4 - Elements) & 3, (5 - Elements) & 3, (6 - Elements) & 3, (7 - Elements) & 3>(V);
}

} // namespace AVX

} // namespace DirectX;