Make sure frexp() returns correct for argument 0.0

[gromacs.git] / src / gromacs / simd / impl_arm_neon_asimd / impl_arm_neon_asimd_simd_double.h

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#ifndef GMX_SIMD_IMPL_ARM_NEON_ASIMD_SIMD_DOUBLE_H
#define GMX_SIMD_IMPL_ARM_NEON_ASIMD_SIMD_DOUBLE_H

#include "config.h"

#include <cassert>

#include <arm_neon.h>

#include "gromacs/math/utilities.h"

#include "impl_arm_neon_asimd_simd_float.h"

namespace gmx
{

class SimdDouble
{
public:
    SimdDouble() {}

    SimdDouble(double d) : simdInternal_(vdupq_n_f64(d)) {}

    // Internal utility constructor to simplify return statements
    SimdDouble(float64x2_t simd) : simdInternal_(simd) {}

    float64x2_t simdInternal_;
};

class SimdDInt32
{
public:
    SimdDInt32() {}

    SimdDInt32(std::int32_t i) : simdInternal_(vdup_n_s32(i)) {}

    // Internal utility constructor to simplify return statements
    SimdDInt32(int32x2_t simd) : simdInternal_(simd) {}

    int32x2_t simdInternal_;
};

class SimdDBool
{
public:
    SimdDBool() {}

    SimdDBool(bool b) : simdInternal_(vdupq_n_u64(b ? 0xFFFFFFFFFFFFFFFF : 0)) {}

    // Internal utility constructor to simplify return statements
    SimdDBool(uint64x2_t simd) : simdInternal_(simd) {}

    uint64x2_t simdInternal_;
};

class SimdDIBool
{
public:
    SimdDIBool() {}

    SimdDIBool(bool b) : simdInternal_(vdup_n_u32(b ? 0xFFFFFFFF : 0)) {}

    // Internal utility constructor to simplify return statements
    SimdDIBool(uint32x2_t simd) : simdInternal_(simd) {}

    uint32x2_t simdInternal_;
};

static inline SimdDouble gmx_simdcall simdLoad(const double* m, SimdDoubleTag = {})
{
    assert(std::size_t(m) % 16 == 0);
    return { vld1q_f64(m) };
}

static inline void gmx_simdcall store(double* m, SimdDouble a)
{
    assert(std::size_t(m) % 16 == 0);
    vst1q_f64(m, a.simdInternal_);
}

static inline SimdDouble gmx_simdcall simdLoadU(const double* m, SimdDoubleTag = {})
{
    return { vld1q_f64(m) };
}

static inline void gmx_simdcall storeU(double* m, SimdDouble a)
{
    vst1q_f64(m, a.simdInternal_);
}

static inline SimdDouble gmx_simdcall setZeroD()
{
    return { vdupq_n_f64(0.0) };
}

static inline SimdDInt32 gmx_simdcall simdLoad(const std::int32_t* m, SimdDInt32Tag)
{
    assert(std::size_t(m) % 8 == 0);
    return { vld1_s32(m) };
}

static inline void gmx_simdcall store(std::int32_t* m, SimdDInt32 a)
{
    assert(std::size_t(m) % 8 == 0);
    vst1_s32(m, a.simdInternal_);
}

static inline SimdDInt32 gmx_simdcall simdLoadU(const std::int32_t* m, SimdDInt32Tag)
{
    return { vld1_s32(m) };
}

static inline void gmx_simdcall storeU(std::int32_t* m, SimdDInt32 a)
{
    vst1_s32(m, a.simdInternal_);
}

static inline SimdDInt32 gmx_simdcall setZeroDI()
{
    return { vdup_n_s32(0) };
}

template<int index>
gmx_simdcall static inline std::int32_t extract(SimdDInt32 a)
{
    return vget_lane_s32(a.simdInternal_, index);
}

static inline SimdDouble gmx_simdcall operator&(SimdDouble a, SimdDouble b)
{
    return { float64x2_t(vandq_s64(int64x2_t(a.simdInternal_), int64x2_t(b.simdInternal_))) };
}

static inline SimdDouble gmx_simdcall andNot(SimdDouble a, SimdDouble b)
{
    return { float64x2_t(vbicq_s64(int64x2_t(b.simdInternal_), int64x2_t(a.simdInternal_))) };
}

static inline SimdDouble gmx_simdcall operator|(SimdDouble a, SimdDouble b)
{
    return { float64x2_t(vorrq_s64(int64x2_t(a.simdInternal_), int64x2_t(b.simdInternal_))) };
}

static inline SimdDouble gmx_simdcall operator^(SimdDouble a, SimdDouble b)
{
    return { float64x2_t(veorq_s64(int64x2_t(a.simdInternal_), int64x2_t(b.simdInternal_))) };
}

static inline SimdDouble gmx_simdcall operator+(SimdDouble a, SimdDouble b)
{
    return { vaddq_f64(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDouble gmx_simdcall operator-(SimdDouble a, SimdDouble b)
{
    return { vsubq_f64(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDouble gmx_simdcall operator-(SimdDouble x)
{
    return { vnegq_f64(x.simdInternal_) };
}

static inline SimdDouble gmx_simdcall operator*(SimdDouble a, SimdDouble b)
{
    return { vmulq_f64(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDouble gmx_simdcall fma(SimdDouble a, SimdDouble b, SimdDouble c)
{
    return { vfmaq_f64(c.simdInternal_, b.simdInternal_, a.simdInternal_) };
}

static inline SimdDouble gmx_simdcall fms(SimdDouble a, SimdDouble b, SimdDouble c)
{
    return { vnegq_f64(vfmsq_f64(c.simdInternal_, b.simdInternal_, a.simdInternal_)) };
}

static inline SimdDouble gmx_simdcall fnma(SimdDouble a, SimdDouble b, SimdDouble c)
{
    return { vfmsq_f64(c.simdInternal_, b.simdInternal_, a.simdInternal_) };
}

static inline SimdDouble gmx_simdcall fnms(SimdDouble a, SimdDouble b, SimdDouble c)
{
    return { vnegq_f64(vfmaq_f64(c.simdInternal_, b.simdInternal_, a.simdInternal_)) };
}

static inline SimdDouble gmx_simdcall rsqrt(SimdDouble x)
{
    return { vrsqrteq_f64(x.simdInternal_) };
}

static inline SimdDouble gmx_simdcall rsqrtIter(SimdDouble lu, SimdDouble x)
{
    return { vmulq_f64(lu.simdInternal_,
                       vrsqrtsq_f64(vmulq_f64(lu.simdInternal_, lu.simdInternal_), x.simdInternal_)) };
}

static inline SimdDouble gmx_simdcall rcp(SimdDouble x)
{
    return { vrecpeq_f64(x.simdInternal_) };
}

static inline SimdDouble gmx_simdcall rcpIter(SimdDouble lu, SimdDouble x)
{
    return { vmulq_f64(lu.simdInternal_, vrecpsq_f64(lu.simdInternal_, x.simdInternal_)) };
}

static inline SimdDouble gmx_simdcall maskAdd(SimdDouble a, SimdDouble b, SimdDBool m)
{
    float64x2_t addend = float64x2_t(vandq_u64(uint64x2_t(b.simdInternal_), m.simdInternal_));

    return { vaddq_f64(a.simdInternal_, addend) };
}

static inline SimdDouble gmx_simdcall maskzMul(SimdDouble a, SimdDouble b, SimdDBool m)
{
    float64x2_t prod = vmulq_f64(a.simdInternal_, b.simdInternal_);
    return { float64x2_t(vandq_u64(uint64x2_t(prod), m.simdInternal_)) };
}

static inline SimdDouble gmx_simdcall maskzFma(SimdDouble a, SimdDouble b, SimdDouble c, SimdDBool m)
{
    float64x2_t prod = vfmaq_f64(c.simdInternal_, b.simdInternal_, a.simdInternal_);

    return { float64x2_t(vandq_u64(uint64x2_t(prod), m.simdInternal_)) };
}

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_ = vbslq_f64(m.simdInternal_, x.simdInternal_, vdupq_n_f64(1.0));
#endif
    return { float64x2_t(vandq_u64(uint64x2_t(vrsqrteq_f64(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_ = vbslq_f64(m.simdInternal_, x.simdInternal_, vdupq_n_f64(1.0));
#endif
    return { float64x2_t(vandq_u64(uint64x2_t(vrecpeq_f64(x.simdInternal_)), m.simdInternal_)) };
}

static inline SimdDouble gmx_simdcall abs(SimdDouble x)
{
    return { vabsq_f64(x.simdInternal_) };
}

static inline SimdDouble gmx_simdcall max(SimdDouble a, SimdDouble b)
{
    return { vmaxq_f64(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDouble gmx_simdcall min(SimdDouble a, SimdDouble b)
{
    return { vminq_f64(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDouble gmx_simdcall round(SimdDouble x)
{
    return { vrndnq_f64(x.simdInternal_) };
}

static inline SimdDouble gmx_simdcall trunc(SimdDouble x)
{
    return { vrndq_f64(x.simdInternal_) };
}

template<MathOptimization opt = MathOptimization::Safe>
static inline SimdDouble frexp(SimdDouble value, SimdDInt32* exponent)
{
    const float64x2_t exponentMask = float64x2_t(vdupq_n_s64(0x7FF0000000000000LL));
    const float64x2_t mantissaMask = float64x2_t(vdupq_n_s64(0x800FFFFFFFFFFFFFLL));

    const int64x2_t exponentBias = vdupq_n_s64(1022); // add 1 to make our definition identical to frexp()
    const float64x2_t half = vdupq_n_f64(0.5);
    int64x2_t         iExponent;

    iExponent               = vandq_s64(int64x2_t(value.simdInternal_), int64x2_t(exponentMask));
    iExponent               = vsubq_s64(vshrq_n_s64(iExponent, 52), exponentBias);
    exponent->simdInternal_ = vmovn_s64(iExponent);

    return { float64x2_t(vorrq_s64(
            vandq_s64(int64x2_t(value.simdInternal_), int64x2_t(mantissaMask)), int64x2_t(half))) };
}

template<MathOptimization opt = MathOptimization::Safe>
static inline SimdDouble ldexp(SimdDouble value, SimdDInt32 exponent)
{
    const int32x2_t exponentBias = vdup_n_s32(1023);
    int32x2_t       iExponent    = vadd_s32(exponent.simdInternal_, exponentBias);
    int64x2_t       iExponent64;

    if (opt == MathOptimization::Safe)
    {
        // Make sure biased argument is not negative
        iExponent = vmax_s32(iExponent, vdup_n_s32(0));
    }

    iExponent64 = vmovl_s32(iExponent);
    iExponent64 = vshlq_n_s64(iExponent64, 52);

    return { vmulq_f64(value.simdInternal_, float64x2_t(iExponent64)) };
}

static inline double gmx_simdcall reduce(SimdDouble a)
{
    float64x2_t b = vpaddq_f64(a.simdInternal_, a.simdInternal_);
    return vgetq_lane_f64(b, 0);
}

static inline SimdDBool gmx_simdcall operator==(SimdDouble a, SimdDouble b)
{
    return { vceqq_f64(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDBool gmx_simdcall operator!=(SimdDouble a, SimdDouble b)
{
    return { vreinterpretq_u64_u32(
            vmvnq_u32(vreinterpretq_u32_u64(vceqq_f64(a.simdInternal_, b.simdInternal_)))) };
}

static inline SimdDBool gmx_simdcall operator<(SimdDouble a, SimdDouble b)
{
    return { vcltq_f64(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDBool gmx_simdcall operator<=(SimdDouble a, SimdDouble b)
{
    return { vcleq_f64(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDBool gmx_simdcall testBits(SimdDouble a)
{
    return { vtstq_s64(int64x2_t(a.simdInternal_), int64x2_t(a.simdInternal_)) };
}

static inline SimdDBool gmx_simdcall operator&&(SimdDBool a, SimdDBool b)
{
    return { vandq_u64(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDBool gmx_simdcall operator||(SimdDBool a, SimdDBool b)
{
    return { vorrq_u64(a.simdInternal_, b.simdInternal_) };
}

static inline bool gmx_simdcall anyTrue(SimdDBool a)
{
    return (vmaxvq_u32((uint32x4_t)(a.simdInternal_)) != 0);
}

static inline SimdDouble gmx_simdcall selectByMask(SimdDouble a, SimdDBool m)
{
    return { float64x2_t(vandq_u64(uint64x2_t(a.simdInternal_), m.simdInternal_)) };
}

static inline SimdDouble gmx_simdcall selectByNotMask(SimdDouble a, SimdDBool m)
{
    return { float64x2_t(vbicq_u64(uint64x2_t(a.simdInternal_), m.simdInternal_)) };
}

static inline SimdDouble gmx_simdcall blend(SimdDouble a, SimdDouble b, SimdDBool sel)
{
    return { vbslq_f64(sel.simdInternal_, b.simdInternal_, a.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall operator&(SimdDInt32 a, SimdDInt32 b)
{
    return { vand_s32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall andNot(SimdDInt32 a, SimdDInt32 b)
{
    return { vbic_s32(b.simdInternal_, a.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall operator|(SimdDInt32 a, SimdDInt32 b)
{
    return { vorr_s32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall operator^(SimdDInt32 a, SimdDInt32 b)
{
    return { veor_s32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall operator+(SimdDInt32 a, SimdDInt32 b)
{
    return { vadd_s32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall operator-(SimdDInt32 a, SimdDInt32 b)
{
    return { vsub_s32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall operator*(SimdDInt32 a, SimdDInt32 b)
{
    return { vmul_s32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDIBool gmx_simdcall operator==(SimdDInt32 a, SimdDInt32 b)
{
    return { vceq_s32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDIBool gmx_simdcall testBits(SimdDInt32 a)
{
    return { vtst_s32(a.simdInternal_, a.simdInternal_) };
}

static inline SimdDIBool gmx_simdcall operator<(SimdDInt32 a, SimdDInt32 b)
{
    return { vclt_s32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDIBool gmx_simdcall operator&&(SimdDIBool a, SimdDIBool b)
{
    return { vand_u32(a.simdInternal_, b.simdInternal_) };
}

static inline SimdDIBool gmx_simdcall operator||(SimdDIBool a, SimdDIBool b)
{
    return { vorr_u32(a.simdInternal_, b.simdInternal_) };
}

static inline bool gmx_simdcall anyTrue(SimdDIBool a)
{
    return (vmaxv_u32(a.simdInternal_) != 0);
}

static inline SimdDInt32 gmx_simdcall selectByMask(SimdDInt32 a, SimdDIBool m)
{
    return { vand_s32(a.simdInternal_, vreinterpret_s32_u32(m.simdInternal_)) };
}

static inline SimdDInt32 gmx_simdcall selectByNotMask(SimdDInt32 a, SimdDIBool m)
{
    return { vbic_s32(a.simdInternal_, vreinterpret_s32_u32(m.simdInternal_)) };
}

static inline SimdDInt32 gmx_simdcall blend(SimdDInt32 a, SimdDInt32 b, SimdDIBool sel)
{
    return { vbsl_s32(sel.simdInternal_, b.simdInternal_, a.simdInternal_) };
}

static inline SimdDInt32 gmx_simdcall cvtR2I(SimdDouble a)
{
    return { vmovn_s64(vcvtnq_s64_f64(a.simdInternal_)) };
}

static inline SimdDInt32 gmx_simdcall cvttR2I(SimdDouble a)
{
    return { vmovn_s64(vcvtq_s64_f64(a.simdInternal_)) };
}

static inline SimdDouble gmx_simdcall cvtI2R(SimdDInt32 a)
{
    return { vcvtq_f64_s64(vmovl_s32(a.simdInternal_)) };
}

static inline SimdDIBool gmx_simdcall cvtB2IB(SimdDBool a)
{
    return { vqmovn_u64(a.simdInternal_) };
}

static inline SimdDBool gmx_simdcall cvtIB2B(SimdDIBool a)
{
    return { vorrq_u64(vmovl_u32(a.simdInternal_), vshlq_n_u64(vmovl_u32(a.simdInternal_), 32)) };
}

static inline void gmx_simdcall cvtF2DD(SimdFloat f, SimdDouble* d0, SimdDouble* d1)
{
    d0->simdInternal_ = vcvt_f64_f32(vget_low_f32(f.simdInternal_));
    d1->simdInternal_ = vcvt_high_f64_f32(f.simdInternal_);
}

static inline SimdFloat gmx_simdcall cvtDD2F(SimdDouble d0, SimdDouble d1)
{
    return { vcvt_high_f32_f64(vcvt_f32_f64(d0.simdInternal_), d1.simdInternal_) };
}

} // namespace gmx

#endif // GMX_SIMD_IMPL_ARM_NEON_ASIMD_SIMD_DOUBLE_H