Make sure frexp() returns correct for argument 0.0

[gromacs.git] / src / gromacs / simd / impl_x86_avx_512 / impl_x86_avx_512_simd_float.h

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#ifndef GMX_SIMD_IMPL_X86_AVX_512_SIMD_FLOAT_H
#define GMX_SIMD_IMPL_X86_AVX_512_SIMD_FLOAT_H

#include "config.h"

#include <cassert>
#include <cstdint>

#include <immintrin.h>

#include "gromacs/math/utilities.h"
#include "gromacs/utility/real.h"

#include "impl_x86_avx_512_general.h"

namespace gmx
{

class SimdFloat
{
public:
    SimdFloat() {}

    SimdFloat(float f) : simdInternal_(_mm512_set1_ps(f)) {}

    // Internal utility constructor to simplify return statements
    SimdFloat(__m512 simd) : simdInternal_(simd) {}

    __m512 simdInternal_;
};

class SimdFInt32
{
public:
    SimdFInt32() {}

    SimdFInt32(std::int32_t i) : simdInternal_(_mm512_set1_epi32(i)) {}

    // Internal utility constructor to simplify return statements
    SimdFInt32(__m512i simd) : simdInternal_(simd) {}

    __m512i simdInternal_;
};

class SimdFBool
{
public:
    SimdFBool() {}

    // Internal utility constructor to simplify return statements
    SimdFBool(__mmask16 simd) : simdInternal_(simd) {}

    __mmask16 simdInternal_;
};

class SimdFIBool
{
public:
    SimdFIBool() {}

    // Internal utility constructor to simplify return statements
    SimdFIBool(__mmask16 simd) : simdInternal_(simd) {}

    __mmask16 simdInternal_;
};

static inline SimdFloat gmx_simdcall simdLoad(const float* m, SimdFloatTag = {})
{
    assert(std::size_t(m) % 64 == 0);
    return { _mm512_load_ps(m) };
}

static inline void gmx_simdcall store(float* m, SimdFloat a)
{
    assert(std::size_t(m) % 64 == 0);
    _mm512_store_ps(m, a.simdInternal_);
}

static inline SimdFloat gmx_simdcall simdLoadU(const float* m, SimdFloatTag = {})
{
    return { _mm512_loadu_ps(m) };
}

static inline void gmx_simdcall storeU(float* m, SimdFloat a)
{
    _mm512_storeu_ps(m, a.simdInternal_);
}

static inline SimdFloat gmx_simdcall setZeroF()
{
    return { _mm512_setzero_ps() };
}

static inline SimdFInt32 gmx_simdcall simdLoad(const std::int32_t* m, SimdFInt32Tag)
{
    assert(std::size_t(m) % 64 == 0);
    return { _mm512_load_si512(m) };
}

static inline void gmx_simdcall store(std::int32_t* m, SimdFInt32 a)
{
    assert(std::size_t(m) % 64 == 0);
    _mm512_store_si512(m, a.simdInternal_);
}

static inline SimdFInt32 gmx_simdcall simdLoadU(const std::int32_t* m, SimdFInt32Tag)
{
    return { _mm512_loadu_si512(m) };
}

static inline void gmx_simdcall storeU(std::int32_t* m, SimdFInt32 a)
{
    _mm512_storeu_si512(m, a.simdInternal_);
}

static inline SimdFInt32 gmx_simdcall setZeroFI()
{
    return { _mm512_setzero_si512() };
}


static inline SimdFloat gmx_simdcall operator&(SimdFloat a, SimdFloat b)
{
    return { _mm512_castsi512_ps(_mm512_and_epi32(_mm512_castps_si512(a.simdInternal_),
                                                  _mm512_castps_si512(b.simdInternal_))) };
}

static inline SimdFloat gmx_simdcall andNot(SimdFloat a, SimdFloat b)
{
    return { _mm512_castsi512_ps(_mm512_andnot_epi32(_mm512_castps_si512(a.simdInternal_),
                                                     _mm512_castps_si512(b.simdInternal_))) };
}

static inline SimdFloat gmx_simdcall operator|(SimdFloat a, SimdFloat b)
{
    return { _mm512_castsi512_ps(_mm512_or_epi32(_mm512_castps_si512(a.simdInternal_),
                                                 _mm512_castps_si512(b.simdInternal_))) };
}

static inline SimdFloat gmx_simdcall operator^(SimdFloat a, SimdFloat b)
{
    return { _mm512_castsi512_ps(_mm512_xor_epi32(_mm512_castps_si512(a.simdInternal_),
                                                  _mm512_castps_si512(b.simdInternal_))) };
}

static inline SimdFloat gmx_simdcall operator+(SimdFloat a, SimdFloat b)
{
    return { _mm512_add_ps(a.simdInternal_, b.simdInternal_) };
}

static inline SimdFloat gmx_simdcall operator-(SimdFloat a, SimdFloat b)
{
    return { _mm512_sub_ps(a.simdInternal_, b.simdInternal_) };
}

static inline SimdFloat gmx_simdcall operator-(SimdFloat x)
{
    return { _mm512_castsi512_ps(_mm512_xor_epi32(_mm512_castps_si512(x.simdInternal_),
                                                  _mm512_castps_si512(_mm512_set1_ps(GMX_FLOAT_NEGZERO)))) };
}

static inline SimdFloat gmx_simdcall operator*(SimdFloat a, SimdFloat b)
{
    return { _mm512_mul_ps(a.simdInternal_, b.simdInternal_) };
}

static inline SimdFloat gmx_simdcall fma(SimdFloat a, SimdFloat b, SimdFloat c)
{
    return { _mm512_fmadd_ps(a.simdInternal_, b.simdInternal_, c.simdInternal_) };
}

static inline SimdFloat gmx_simdcall fms(SimdFloat a, SimdFloat b, SimdFloat c)
{
    return { _mm512_fmsub_ps(a.simdInternal_, b.simdInternal_, c.simdInternal_) };
}

static inline SimdFloat gmx_simdcall fnma(SimdFloat a, SimdFloat b, SimdFloat c)
{
    return { _mm512_fnmadd_ps(a.simdInternal_, b.simdInternal_, c.simdInternal_) };
}

static inline SimdFloat gmx_simdcall fnms(SimdFloat a, SimdFloat b, SimdFloat c)
{
    return { _mm512_fnmsub_ps(a.simdInternal_, b.simdInternal_, c.simdInternal_) };
}

// Override for AVX-512-KNL
#if GMX_SIMD_X86_AVX_512
static inline SimdFloat gmx_simdcall rsqrt(SimdFloat x)
{
    return { _mm512_rsqrt14_ps(x.simdInternal_) };
}

static inline SimdFloat gmx_simdcall rcp(SimdFloat x)
{
    return { _mm512_rcp14_ps(x.simdInternal_) };
}
#endif

static inline SimdFloat gmx_simdcall maskAdd(SimdFloat a, SimdFloat b, SimdFBool m)
{
    return { _mm512_mask_add_ps(a.simdInternal_, m.simdInternal_, a.simdInternal_, b.simdInternal_) };
}

static inline SimdFloat gmx_simdcall maskzMul(SimdFloat a, SimdFloat b, SimdFBool m)
{
    return { _mm512_maskz_mul_ps(m.simdInternal_, a.simdInternal_, b.simdInternal_) };
}

static inline SimdFloat gmx_simdcall maskzFma(SimdFloat a, SimdFloat b, SimdFloat c, SimdFBool m)
{
    return { _mm512_maskz_fmadd_ps(m.simdInternal_, a.simdInternal_, b.simdInternal_, c.simdInternal_) };
}

// Override for AVX-512-KNL
#if GMX_SIMD_X86_AVX_512
static inline SimdFloat gmx_simdcall maskzRsqrt(SimdFloat x, SimdFBool m)
{
    return { _mm512_maskz_rsqrt14_ps(m.simdInternal_, x.simdInternal_) };
}

static inline SimdFloat gmx_simdcall maskzRcp(SimdFloat x, SimdFBool m)
{
    return { _mm512_maskz_rcp14_ps(m.simdInternal_, x.simdInternal_) };
}
#endif

static inline SimdFloat gmx_simdcall abs(SimdFloat x)
{
    return { _mm512_castsi512_ps(_mm512_andnot_epi32(_mm512_castps_si512(_mm512_set1_ps(GMX_FLOAT_NEGZERO)),
                                                     _mm512_castps_si512(x.simdInternal_))) };
}

static inline SimdFloat gmx_simdcall max(SimdFloat a, SimdFloat b)
{
    return { _mm512_max_ps(a.simdInternal_, b.simdInternal_) };
}

static inline SimdFloat gmx_simdcall min(SimdFloat a, SimdFloat b)
{
    return { _mm512_min_ps(a.simdInternal_, b.simdInternal_) };
}

static inline SimdFloat gmx_simdcall round(SimdFloat x)
{
    return { _mm512_roundscale_ps(x.simdInternal_, 0) };
}

static inline SimdFloat gmx_simdcall trunc(SimdFloat x)
{
#if defined(__INTEL_COMPILER) || defined(__ECC)
    return { _mm512_trunc_ps(x.simdInternal_) };
#else
    return { _mm512_cvtepi32_ps(_mm512_cvttps_epi32(x.simdInternal_)) };
#endif
}

template<MathOptimization opt = MathOptimization::Safe>
static inline SimdFloat gmx_simdcall frexp(SimdFloat value, SimdFInt32* exponent)
{
    __m512  rExponent;
    __m512i iExponent;
    __m512  result;

    if (opt == MathOptimization::Safe)
    {
        // For the safe branch, we use the masked operations to only assign results if the
        // input value was nonzero, and otherwise set exponent to 0, and the fraction to the input (+-0).
        __mmask16 valueIsNonZero =
                _mm512_cmp_ps_mask(_mm512_setzero_ps(), value.simdInternal_, _CMP_NEQ_OQ);
        rExponent = _mm512_mask_getexp_ps(_mm512_setzero_ps(), valueIsNonZero, value.simdInternal_);
        iExponent = _mm512_cvtps_epi32(rExponent);
        iExponent = _mm512_mask_add_epi32(iExponent, valueIsNonZero, iExponent, _mm512_set1_epi32(1));

        // Set result to input value when the latter is +-0
        result = _mm512_mask_getmant_ps(value.simdInternal_, valueIsNonZero, value.simdInternal_,
                                        _MM_MANT_NORM_p5_1, _MM_MANT_SIGN_src);
    }
    else
    {
        // For the fast branch, it's the user's responsibility to make sure never to call the
        // function with input values of +-0.0
        rExponent = _mm512_getexp_ps(value.simdInternal_);
        iExponent = _mm512_cvtps_epi32(rExponent);
        iExponent = _mm512_add_epi32(iExponent, _mm512_set1_epi32(1));

        result = _mm512_getmant_ps(value.simdInternal_, _MM_MANT_NORM_p5_1, _MM_MANT_SIGN_src);
    }

    exponent->simdInternal_ = iExponent;

    return { result };
}

template<MathOptimization opt = MathOptimization::Safe>
static inline SimdFloat gmx_simdcall ldexp(SimdFloat value, SimdFInt32 exponent)
{
    const __m512i exponentBias = _mm512_set1_epi32(127);
    __m512i       iExponent    = _mm512_add_epi32(exponent.simdInternal_, exponentBias);

    if (opt == MathOptimization::Safe)
    {
        // Make sure biased argument is not negative
        iExponent = _mm512_max_epi32(iExponent, _mm512_setzero_epi32());
    }

    iExponent = _mm512_slli_epi32(iExponent, 23);

    return { _mm512_mul_ps(value.simdInternal_, _mm512_castsi512_ps(iExponent)) };
}

static inline float gmx_simdcall reduce(SimdFloat a)
{
    __m512 x = a.simdInternal_;
    x        = _mm512_add_ps(x, _mm512_shuffle_f32x4(x, x, 0xEE));
    x        = _mm512_add_ps(x, _mm512_shuffle_f32x4(x, x, 0x11));
    x        = _mm512_add_ps(x, _mm512_permute_ps(x, 0xEE));
    x        = _mm512_add_ps(x, _mm512_permute_ps(x, 0x11));
    return *reinterpret_cast<float*>(&x);
}

static inline SimdFBool gmx_simdcall operator==(SimdFloat a, SimdFloat b)
{
    return { _mm512_cmp_ps_mask(a.simdInternal_, b.simdInternal_, _CMP_EQ_OQ) };
}

static inline SimdFBool gmx_simdcall operator!=(SimdFloat a, SimdFloat b)
{
    return { _mm512_cmp_ps_mask(a.simdInternal_, b.simdInternal_, _CMP_NEQ_OQ) };
}

static inline SimdFBool gmx_simdcall operator<(SimdFloat a, SimdFloat b)
{
    return { _mm512_cmp_ps_mask(a.simdInternal_, b.simdInternal_, _CMP_LT_OQ) };
}

static inline SimdFBool gmx_simdcall operator<=(SimdFloat a, SimdFloat b)
{
    return { _mm512_cmp_ps_mask(a.simdInternal_, b.simdInternal_, _CMP_LE_OQ) };
}

static inline SimdFBool gmx_simdcall testBits(SimdFloat a)
{
    return { _mm512_test_epi32_mask(_mm512_castps_si512(a.simdInternal_),
                                    _mm512_castps_si512(a.simdInternal_)) };
}

static inline SimdFBool gmx_simdcall operator&&(SimdFBool a, SimdFBool b)
{
    return { _mm512_kand(a.simdInternal_, b.simdInternal_) };
}

static inline SimdFBool gmx_simdcall operator||(SimdFBool a, SimdFBool b)
{
    return { _mm512_kor(a.simdInternal_, b.simdInternal_) };
}

static inline bool gmx_simdcall anyTrue(SimdFBool a)
{
    return (avx512Mask2Int(a.simdInternal_) != 0);
}

static inline SimdFloat gmx_simdcall selectByMask(SimdFloat a, SimdFBool m)
{
    return { _mm512_mask_mov_ps(_mm512_setzero_ps(), m.simdInternal_, a.simdInternal_) };
}

static inline SimdFloat gmx_simdcall selectByNotMask(SimdFloat a, SimdFBool m)
{
    return { _mm512_mask_mov_ps(a.simdInternal_, m.simdInternal_, _mm512_setzero_ps()) };
}

static inline SimdFloat gmx_simdcall blend(SimdFloat a, SimdFloat b, SimdFBool sel)
{
    return { _mm512_mask_blend_ps(sel.simdInternal_, a.simdInternal_, b.simdInternal_) };
}

static inline SimdFloat gmx_simdcall copysign(SimdFloat a, SimdFloat b)
{
    return { _mm512_castsi512_ps(_mm512_ternarylogic_epi32(_mm512_castps_si512(a.simdInternal_),
                                                           _mm512_castps_si512(b.simdInternal_),
                                                           _mm512_set1_epi32(INT32_MIN), 0xD8)) };
}

static inline SimdFInt32 gmx_simdcall operator&(SimdFInt32 a, SimdFInt32 b)
{
    return { _mm512_and_epi32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdFInt32 gmx_simdcall andNot(SimdFInt32 a, SimdFInt32 b)
{
    return { _mm512_andnot_epi32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdFInt32 gmx_simdcall operator|(SimdFInt32 a, SimdFInt32 b)
{
    return { _mm512_or_epi32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdFInt32 gmx_simdcall operator^(SimdFInt32 a, SimdFInt32 b)
{
    return { _mm512_xor_epi32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdFInt32 gmx_simdcall operator+(SimdFInt32 a, SimdFInt32 b)
{
    return { _mm512_add_epi32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdFInt32 gmx_simdcall operator-(SimdFInt32 a, SimdFInt32 b)
{
    return { _mm512_sub_epi32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdFInt32 gmx_simdcall operator*(SimdFInt32 a, SimdFInt32 b)
{
    return { _mm512_mullo_epi32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdFIBool gmx_simdcall operator==(SimdFInt32 a, SimdFInt32 b)
{
    return { _mm512_cmp_epi32_mask(a.simdInternal_, b.simdInternal_, _MM_CMPINT_EQ) };
}

static inline SimdFIBool gmx_simdcall testBits(SimdFInt32 a)
{
    return { _mm512_test_epi32_mask(a.simdInternal_, a.simdInternal_) };
}

static inline SimdFIBool gmx_simdcall operator<(SimdFInt32 a, SimdFInt32 b)
{
    return { _mm512_cmp_epi32_mask(a.simdInternal_, b.simdInternal_, _MM_CMPINT_LT) };
}

static inline SimdFIBool gmx_simdcall operator&&(SimdFIBool a, SimdFIBool b)
{
    return { _mm512_kand(a.simdInternal_, b.simdInternal_) };
}

static inline SimdFIBool gmx_simdcall operator||(SimdFIBool a, SimdFIBool b)
{
    return { _mm512_kor(a.simdInternal_, b.simdInternal_) };
}

static inline bool gmx_simdcall anyTrue(SimdFIBool a)
{
    return (avx512Mask2Int(a.simdInternal_) != 0);
}

static inline SimdFInt32 gmx_simdcall selectByMask(SimdFInt32 a, SimdFIBool m)
{
    return { _mm512_mask_mov_epi32(_mm512_setzero_epi32(), m.simdInternal_, a.simdInternal_) };
}

static inline SimdFInt32 gmx_simdcall selectByNotMask(SimdFInt32 a, SimdFIBool m)
{
    return { _mm512_mask_mov_epi32(a.simdInternal_, m.simdInternal_, _mm512_setzero_epi32()) };
}

static inline SimdFInt32 gmx_simdcall blend(SimdFInt32 a, SimdFInt32 b, SimdFIBool sel)
{
    return { _mm512_mask_blend_epi32(sel.simdInternal_, a.simdInternal_, b.simdInternal_) };
}

static inline SimdFInt32 gmx_simdcall cvtR2I(SimdFloat a)
{
    return { _mm512_cvtps_epi32(a.simdInternal_) };
}

static inline SimdFInt32 gmx_simdcall cvttR2I(SimdFloat a)
{
    return { _mm512_cvttps_epi32(a.simdInternal_) };
}

static inline SimdFloat gmx_simdcall cvtI2R(SimdFInt32 a)
{
    return { _mm512_cvtepi32_ps(a.simdInternal_) };
}

static inline SimdFIBool gmx_simdcall cvtB2IB(SimdFBool a)
{
    return { a.simdInternal_ };
}

static inline SimdFBool gmx_simdcall cvtIB2B(SimdFIBool a)
{
    return { a.simdInternal_ };
}

} // namespace gmx

#endif // GMX_SIMD_IMPL_X86_AVX_512_SIMD_FLOAT_H