/*
 * This file is part of the GROMACS molecular simulation package.
 *
 * Copyright 2014- The GROMACS Authors
 * and the project initiators Erik Lindahl, Berk Hess and David van der Spoel.
 * Consult the AUTHORS/COPYING files and https://www.gromacs.org for details.
 *
 * GROMACS is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1
 * of the License, or (at your option) any later version.
 *
 * GROMACS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with GROMACS; if not, see
 * https://www.gnu.org/licenses, or write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA.
 *
 * If you want to redistribute modifications to GROMACS, please
 * consider that scientific software is very special. Version
 * control is crucial - bugs must be traceable. We will be happy to
 * consider code for inclusion in the official distribution, but
 * derived work must not be called official GROMACS. Details are found
 * in the README & COPYING files - if they are missing, get the
 * official version at https://www.gromacs.org.
 *
 * To help us fund GROMACS development, we humbly ask that you cite
 * the research papers on the package. Check out https://www.gromacs.org.
 */
#ifndef GMX_SIMD_IMPL_X86_SSE2_SIMD_DOUBLE_H
#define GMX_SIMD_IMPL_X86_SSE2_SIMD_DOUBLE_H

#include "config.h"

#include <emmintrin.h>

#include <cassert>
#include <cstddef>
#include <cstdint>

#include "gromacs/math/utilities.h"
#include "gromacs/simd/impl_x86_sse2/impl_x86_sse2_simd_float.h"

namespace gmx
{

class SimdDouble
{
public:
    SimdDouble() {}

    SimdDouble(double d) : simdInternal_(_mm_set1_pd(d)) {}

    // Internal utility constructor to simplify return statements
    SimdDouble(__m128d simd) : simdInternal_(simd) {}

    __m128d simdInternal_;
};

class SimdDInt32
{
public:
    SimdDInt32() {}

    SimdDInt32(std::int32_t i) : simdInternal_(_mm_set1_epi32(i)) {}

    // Internal utility constructor to simplify return statements
    SimdDInt32(__m128i simd) : simdInternal_(simd) {}

    __m128i simdInternal_;
};

class SimdDBool
{
public:
    SimdDBool() {}

    SimdDBool(bool b) : simdInternal_(_mm_castsi128_pd(_mm_set1_epi32(b ? 0xFFFFFFFF : 0))) {}

    // Internal utility constructor to simplify return statements
    SimdDBool(__m128d simd) : simdInternal_(simd) {}

    __m128d simdInternal_;
};

class SimdDIBool
{
public:
    SimdDIBool() {}

    SimdDIBool(bool b) : simdInternal_(_mm_set1_epi32(b ? 0xFFFFFFFF : 0)) {}

    // Internal utility constructor to simplify return statements
    SimdDIBool(__m128i simd) : simdInternal_(simd) {}

    __m128i simdInternal_;
};

static inline SimdDouble gmx_simdcall simdLoad(const double* m, SimdDoubleTag = {})
{
    assert(std::size_t(m) % 16 == 0);
    return { _mm_load_pd(m) };
}

static inline void gmx_simdcall store(double* m, SimdDouble a)
{
    assert(std::size_t(m) % 16 == 0);
    _mm_store_pd(m, a.simdInternal_);
}

static inline SimdDouble gmx_simdcall simdLoadU(const double* m, SimdDoubleTag = {})
{
    return { _mm_loadu_pd(m) };
}

static inline void gmx_simdcall storeU(double* m, SimdDouble a)
{
    _mm_storeu_pd(m, a.simdInternal_);
}

static inline SimdDouble gmx_simdcall setZeroD()
{
    return { _mm_setzero_pd() };
}

static inline SimdDInt32 gmx_simdcall simdLoad(const std::int32_t* m, SimdDInt32Tag)
{
    assert(std::size_t(m) % 8 == 0);
    return { _mm_loadl_epi64(reinterpret_cast<const __m128i*>(m)) };
}

static inline void gmx_simdcall store(std::int32_t* m, SimdDInt32 a)
{
    assert(std::size_t(m) % 8 == 0);
    _mm_storel_epi64(reinterpret_cast<__m128i*>(m), a.simdInternal_);
}

static inline SimdDInt32 gmx_simdcall simdLoadU(const std::int32_t* m, SimdDInt32Tag)
{
    return { _mm_loadl_epi64(reinterpret_cast<const __m128i*>(m)) };
}

static inline void gmx_simdcall storeU(std::int32_t* m, SimdDInt32 a)
{
    _mm_storel_epi64(reinterpret_cast<__m128i*>(m), a.simdInternal_);
}

static inline SimdDInt32 gmx_simdcall setZeroDI()
{
    return { _mm_setzero_si128() };
}

// Override for SSE4.1 and higher
#if GMX_SIMD_X86_SSE2
template<int index>
static inline std::int32_t gmx_simdcall extract(SimdDInt32 a)
{
    return _mm_cvtsi128_si32(_mm_srli_si128(a.simdInternal_, 4 * index));
}
#endif

static inline SimdDouble gmx_simdcall operator&(SimdDouble a, SimdDouble b)
{
    return { _mm_and_pd(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDouble gmx_simdcall andNot(SimdDouble a, SimdDouble b)
{
    return { _mm_andnot_pd(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDouble gmx_simdcall operator|(SimdDouble a, SimdDouble b)
{
    return { _mm_or_pd(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDouble gmx_simdcall operator^(SimdDouble a, SimdDouble b)
{
    return { _mm_xor_pd(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDouble gmx_simdcall operator+(SimdDouble a, SimdDouble b)
{
    return { _mm_add_pd(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDouble gmx_simdcall operator-(SimdDouble a, SimdDouble b)
{
    return { _mm_sub_pd(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDouble gmx_simdcall operator-(SimdDouble x)
{
    return { _mm_xor_pd(x.simdInternal_, _mm_set1_pd(GMX_DOUBLE_NEGZERO)) };
}

static inline SimdDouble gmx_simdcall operator*(SimdDouble a, SimdDouble b)
{
    return { _mm_mul_pd(a.simdInternal_, b.simdInternal_) };
}

// Override for AVX-128-FMA and higher
#if GMX_SIMD_X86_SSE2 || GMX_SIMD_X86_SSE4_1
static inline SimdDouble gmx_simdcall fma(SimdDouble a, SimdDouble b, SimdDouble c)
{
    return { _mm_add_pd(_mm_mul_pd(a.simdInternal_, b.simdInternal_), c.simdInternal_) };
}

static inline SimdDouble gmx_simdcall fms(SimdDouble a, SimdDouble b, SimdDouble c)
{
    return { _mm_sub_pd(_mm_mul_pd(a.simdInternal_, b.simdInternal_), c.simdInternal_) };
}

static inline SimdDouble gmx_simdcall fnma(SimdDouble a, SimdDouble b, SimdDouble c)
{
    return { _mm_sub_pd(c.simdInternal_, _mm_mul_pd(a.simdInternal_, b.simdInternal_)) };
}

static inline SimdDouble gmx_simdcall fnms(SimdDouble a, SimdDouble b, SimdDouble c)
{
    return { _mm_sub_pd(_mm_setzero_pd(),
                        _mm_add_pd(_mm_mul_pd(a.simdInternal_, b.simdInternal_), c.simdInternal_)) };
}
#endif

static inline SimdDouble gmx_simdcall rsqrt(SimdDouble x)
{
    return { _mm_cvtps_pd(_mm_rsqrt_ps(_mm_cvtpd_ps(x.simdInternal_))) };
}

static inline SimdDouble gmx_simdcall rcp(SimdDouble x)
{
    return { _mm_cvtps_pd(_mm_rcp_ps(_mm_cvtpd_ps(x.simdInternal_))) };
}

static inline SimdDouble gmx_simdcall maskAdd(SimdDouble a, SimdDouble b, SimdDBool m)
{
    return { _mm_add_pd(a.simdInternal_, _mm_and_pd(b.simdInternal_, m.simdInternal_)) };
}

static inline SimdDouble gmx_simdcall maskzMul(SimdDouble a, SimdDouble b, SimdDBool m)
{
    return { _mm_and_pd(_mm_mul_pd(a.simdInternal_, b.simdInternal_), m.simdInternal_) };
}

static inline SimdDouble gmx_simdcall maskzFma(SimdDouble a, SimdDouble b, SimdDouble c, SimdDBool m)
{
    return { _mm_and_pd(_mm_add_pd(_mm_mul_pd(a.simdInternal_, b.simdInternal_), c.simdInternal_),
                        m.simdInternal_) };
}

// Override for SSE4.1 and higher
#if GMX_SIMD_X86_SSE2
static inline SimdDouble gmx_simdcall maskzRsqrt(SimdDouble x, SimdDBool m)
{
    // The result will always be correct since we mask the result with m, but
    // for debug builds we also want to make sure not to generate FP exceptions
#    ifndef NDEBUG
    x.simdInternal_ = _mm_or_pd(_mm_andnot_pd(m.simdInternal_, _mm_set1_pd(1.0)),
                                _mm_and_pd(m.simdInternal_, x.simdInternal_));
#    endif
    return { _mm_and_pd(_mm_cvtps_pd(_mm_rsqrt_ps(_mm_cvtpd_ps(x.simdInternal_))), m.simdInternal_) };
}

static inline SimdDouble gmx_simdcall maskzRcp(SimdDouble x, SimdDBool m)
{
    // The result will always be correct since we mask the result with m, but
    // for debug builds we also want to make sure not to generate FP exceptions
#    ifndef NDEBUG
    x.simdInternal_ = _mm_or_pd(_mm_andnot_pd(m.simdInternal_, _mm_set1_pd(1.0)),
                                _mm_and_pd(m.simdInternal_, x.simdInternal_));
#    endif
    return { _mm_and_pd(_mm_cvtps_pd(_mm_rcp_ps(_mm_cvtpd_ps(x.simdInternal_))), m.simdInternal_) };
}
#endif

static inline SimdDouble gmx_simdcall abs(SimdDouble x)
{
    return { _mm_andnot_pd(_mm_set1_pd(GMX_DOUBLE_NEGZERO), x.simdInternal_) };
}

static inline SimdDouble gmx_simdcall max(SimdDouble a, SimdDouble b)
{
    return { _mm_max_pd(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDouble gmx_simdcall min(SimdDouble a, SimdDouble b)
{
    return { _mm_min_pd(a.simdInternal_, b.simdInternal_) };
}

// Override for SSE4.1 and higher
#if GMX_SIMD_X86_SSE2
static inline SimdDouble gmx_simdcall round(SimdDouble x)
{
    return { _mm_cvtepi32_pd(_mm_cvtpd_epi32(x.simdInternal_)) };
}

static inline SimdDouble gmx_simdcall trunc(SimdDouble x)
{
    return { _mm_cvtepi32_pd(_mm_cvttpd_epi32(x.simdInternal_)) };
}

#endif

template<MathOptimization opt = MathOptimization::Safe>
static inline SimdDouble frexp(SimdDouble value, SimdDInt32* exponent)
{
    // Don't use _mm_set1_epi64x() - on MSVC it is only supported for 64-bit builds
    const __m128d exponentMask =
            _mm_castsi128_pd(_mm_set_epi32(0x7FF00000, 0x00000000, 0x7FF00000, 0x00000000));
    const __m128d mantissaMask =
            _mm_castsi128_pd(_mm_set_epi32(0x800FFFFF, 0xFFFFFFFF, 0x800FFFFF, 0xFFFFFFFF));
    const __m128i exponentBias = _mm_set1_epi32(1022); // add 1 to make our definition identical to frexp()
    const __m128d half         = _mm_set1_pd(0.5);

    __m128i iExponent = _mm_castpd_si128(_mm_and_pd(value.simdInternal_, exponentMask));
    iExponent         = _mm_sub_epi32(_mm_srli_epi64(iExponent, 52), exponentBias);

    __m128d result = _mm_or_pd(_mm_and_pd(value.simdInternal_, mantissaMask), half);

    if (opt == MathOptimization::Safe)
    {
        __m128d valueIsZero = _mm_cmpeq_pd(_mm_setzero_pd(), value.simdInternal_);
        // Set the upper/lower 64-bit-fields of "iExponent" to 0-bits if the corresponding input value was +-0.0
        iExponent = _mm_andnot_si128(_mm_castpd_si128(valueIsZero), iExponent);
        // Set result to +-0 if the corresponding input value was +-0
        result = _mm_or_pd(_mm_andnot_pd(valueIsZero, result),
                           _mm_and_pd(valueIsZero, value.simdInternal_));
    }

    // Shuffle exponent so that 32-bit-fields 0 & 1 contain the relevant exponent values to return
    exponent->simdInternal_ = _mm_shuffle_epi32(iExponent, _MM_SHUFFLE(3, 1, 2, 0));

    return { result };
}

// Override for SSE4.1
#if GMX_SIMD_X86_SSE2
template<MathOptimization opt = MathOptimization::Safe>
static inline SimdDouble ldexp(SimdDouble value, SimdDInt32 exponent)
{
    const __m128i exponentBias = _mm_set1_epi32(1023);
    __m128i       iExponent    = _mm_add_epi32(exponent.simdInternal_, exponentBias);

    if (opt == MathOptimization::Safe)
    {
        // Make sure biased argument is not negative
        iExponent = _mm_and_si128(iExponent, _mm_cmpgt_epi32(iExponent, _mm_setzero_si128()));
    }

    // After conversion integers will be in slot 0,1. Move them to 0,2 so
    // we can do a 64-bit shift and get them to the dp exponents.
    iExponent = _mm_shuffle_epi32(iExponent, _MM_SHUFFLE(3, 1, 2, 0));
    iExponent = _mm_slli_epi64(iExponent, 52);

    return { _mm_mul_pd(value.simdInternal_, _mm_castsi128_pd(iExponent)) };
}
#endif

// Override for AVX-128-FMA and higher
#if GMX_SIMD_X86_SSE2 || GMX_SIMD_X86_SSE4_1
static inline double gmx_simdcall reduce(SimdDouble a)
{
    __m128d b = _mm_add_sd(a.simdInternal_,
                           _mm_shuffle_pd(a.simdInternal_, a.simdInternal_, _MM_SHUFFLE2(1, 1)));
    return *reinterpret_cast<double*>(&b);
}
#endif

static inline SimdDBool gmx_simdcall operator==(SimdDouble a, SimdDouble b)
{
    return { _mm_cmpeq_pd(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDBool gmx_simdcall operator!=(SimdDouble a, SimdDouble b)
{
    return { _mm_cmpneq_pd(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDBool gmx_simdcall operator<(SimdDouble a, SimdDouble b)
{
    return { _mm_cmplt_pd(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDBool gmx_simdcall operator<=(SimdDouble a, SimdDouble b)
{
    return { _mm_cmple_pd(a.simdInternal_, b.simdInternal_) };
}

// Override for SSE4.1 and higher
#if GMX_SIMD_X86_SSE2
static inline SimdDBool gmx_simdcall testBits(SimdDouble a)
{
    __m128i ia = _mm_castpd_si128(a.simdInternal_);
    __m128i res = _mm_andnot_si128(_mm_cmpeq_epi32(ia, _mm_setzero_si128()), _mm_cmpeq_epi32(ia, ia));

    // set each 64-bit element if low or high 32-bit part is set
    res = _mm_or_si128(res, _mm_shuffle_epi32(res, _MM_SHUFFLE(2, 3, 0, 1)));

    return { _mm_castsi128_pd(res) };
}
#endif

static inline SimdDBool gmx_simdcall operator&&(SimdDBool a, SimdDBool b)
{
    return { _mm_and_pd(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDBool gmx_simdcall operator||(SimdDBool a, SimdDBool b)
{
    return { _mm_or_pd(a.simdInternal_, b.simdInternal_) };
}

static inline bool gmx_simdcall anyTrue(SimdDBool a)
{
    return _mm_movemask_pd(a.simdInternal_) != 0;
}

static inline SimdDouble gmx_simdcall selectByMask(SimdDouble a, SimdDBool mask)
{
    return { _mm_and_pd(a.simdInternal_, mask.simdInternal_) };
}

static inline SimdDouble gmx_simdcall selectByNotMask(SimdDouble a, SimdDBool mask)
{
    return { _mm_andnot_pd(mask.simdInternal_, a.simdInternal_) };
}

// Override for SSE4.1 and higher
#if GMX_SIMD_X86_SSE2
static inline SimdDouble gmx_simdcall blend(SimdDouble a, SimdDouble b, SimdDBool sel)
{
    return { _mm_or_pd(_mm_andnot_pd(sel.simdInternal_, a.simdInternal_),
                       _mm_and_pd(sel.simdInternal_, b.simdInternal_)) };
}
#endif

static inline SimdDInt32 gmx_simdcall operator&(SimdDInt32 a, SimdDInt32 b)
{
    return { _mm_and_si128(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall andNot(SimdDInt32 a, SimdDInt32 b)
{
    return { _mm_andnot_si128(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall operator|(SimdDInt32 a, SimdDInt32 b)
{
    return { _mm_or_si128(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall operator^(SimdDInt32 a, SimdDInt32 b)
{
    return { _mm_xor_si128(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall operator+(SimdDInt32 a, SimdDInt32 b)
{
    return { _mm_add_epi32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall operator-(SimdDInt32 a, SimdDInt32 b)
{
    return { _mm_sub_epi32(a.simdInternal_, b.simdInternal_) };
}

// Override for SSE4.1 and higher
#if GMX_SIMD_X86_SSE2
static inline SimdDInt32 gmx_simdcall operator*(SimdDInt32 a, SimdDInt32 b)
{

    __m128i tmpA = _mm_unpacklo_epi32(a.simdInternal_, _mm_setzero_si128()); // 0 a[1] 0 a[0]
    __m128i tmpB = _mm_unpacklo_epi32(b.simdInternal_, _mm_setzero_si128()); // 0 b[1] 0 b[0]

    __m128i tmpC = _mm_mul_epu32(tmpA, tmpB); // 0 a[1]*b[1] 0 a[0]*b[0]

    return { _mm_shuffle_epi32(tmpC, _MM_SHUFFLE(3, 1, 2, 0)) };
}
#endif

static inline SimdDIBool gmx_simdcall operator==(SimdDInt32 a, SimdDInt32 b)
{
    return { _mm_cmpeq_epi32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDIBool gmx_simdcall testBits(SimdDInt32 a)
{
    __m128i x   = a.simdInternal_;
    __m128i res = _mm_andnot_si128(_mm_cmpeq_epi32(x, _mm_setzero_si128()), _mm_cmpeq_epi32(x, x));

    return { res };
}

static inline SimdDIBool gmx_simdcall operator<(SimdDInt32 a, SimdDInt32 b)
{
    return { _mm_cmplt_epi32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDIBool gmx_simdcall operator&&(SimdDIBool a, SimdDIBool b)
{
    return { _mm_and_si128(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDIBool gmx_simdcall operator||(SimdDIBool a, SimdDIBool b)
{
    return { _mm_or_si128(a.simdInternal_, b.simdInternal_) };
}

static inline bool gmx_simdcall anyTrue(SimdDIBool a)
{
    return _mm_movemask_epi8(_mm_shuffle_epi32(a.simdInternal_, _MM_SHUFFLE(1, 0, 1, 0))) != 0;
}

static inline SimdDInt32 gmx_simdcall selectByMask(SimdDInt32 a, SimdDIBool mask)
{
    return { _mm_and_si128(a.simdInternal_, mask.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall selectByNotMask(SimdDInt32 a, SimdDIBool mask)
{
    return { _mm_andnot_si128(mask.simdInternal_, a.simdInternal_) };
}

// Override for SSE4.1 and higher
#if GMX_SIMD_X86_SSE2
static inline SimdDInt32 gmx_simdcall blend(SimdDInt32 a, SimdDInt32 b, SimdDIBool sel)
{
    return { _mm_or_si128(_mm_andnot_si128(sel.simdInternal_, a.simdInternal_),
                          _mm_and_si128(sel.simdInternal_, b.simdInternal_)) };
}
#endif

static inline SimdDInt32 gmx_simdcall cvtR2I(SimdDouble a)
{
    return { _mm_cvtpd_epi32(a.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall cvttR2I(SimdDouble a)
{
    return { _mm_cvttpd_epi32(a.simdInternal_) };
}

static inline SimdDouble gmx_simdcall cvtI2R(SimdDInt32 a)
{
    return { _mm_cvtepi32_pd(a.simdInternal_) };
}

static inline SimdDIBool gmx_simdcall cvtB2IB(SimdDBool a)
{
    return { _mm_shuffle_epi32(_mm_castpd_si128(a.simdInternal_), _MM_SHUFFLE(2, 0, 2, 0)) };
}

static inline SimdDBool gmx_simdcall cvtIB2B(SimdDIBool a)
{
    return { _mm_castsi128_pd(_mm_shuffle_epi32(a.simdInternal_, _MM_SHUFFLE(1, 1, 0, 0))) };
}

static inline void gmx_simdcall cvtF2DD(SimdFloat f, SimdDouble* d0, SimdDouble* d1)
{
    d0->simdInternal_ = _mm_cvtps_pd(f.simdInternal_);
    d1->simdInternal_ = _mm_cvtps_pd(_mm_movehl_ps(f.simdInternal_, f.simdInternal_));
}

static inline SimdFloat gmx_simdcall cvtDD2F(SimdDouble d0, SimdDouble d1)
{
    return { _mm_movelh_ps(_mm_cvtpd_ps(d0.simdInternal_), _mm_cvtpd_ps(d1.simdInternal_)) };
}

} // namespace gmx

#endif // GMX_SIMD_IMPL_X86_SSE2_SIMD_DOUBLE_H
