Make sure frexp() returns correct for argument 0.0

[gromacs.git] / src / gromacs / simd / impl_ibm_vsx / impl_ibm_vsx_simd_float.h

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#ifndef GMX_SIMD_IMPLEMENTATION_IBM_VSX_SIMD_FLOAT_H
#define GMX_SIMD_IMPLEMENTATION_IBM_VSX_SIMD_FLOAT_H

#include "config.h"

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

#include "impl_ibm_vsx_definitions.h"

namespace gmx
{

class SimdFloat
{
public:
    SimdFloat() {}

    // gcc-4.9 does not recognize that we use the parameter
    SimdFloat(float gmx_unused f) : simdInternal_(vec_splats(f)) {}

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

    __vector float simdInternal_;
};

class SimdFInt32
{
public:
    SimdFInt32() {}

    // gcc-4.9 does not recognize that we use the parameter
    SimdFInt32(std::int32_t gmx_unused i) : simdInternal_(vec_splats(i)) {}

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

    __vector signed int simdInternal_;
};

class SimdFBool
{
public:
    SimdFBool() {}

    SimdFBool(bool b) :
        simdInternal_(reinterpret_cast<__vector vsxBool int>(vec_splats(b ? 0xFFFFFFFF : 0)))
    {
    }

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

    __vector vsxBool int simdInternal_;
};

class SimdFIBool
{
public:
    SimdFIBool() {}

    SimdFIBool(bool b) :
        simdInternal_(reinterpret_cast<__vector vsxBool int>(vec_splats(b ? 0xFFFFFFFF : 0)))
    {
    }

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

    __vector vsxBool int simdInternal_;
};

// Note that the interfaces we use here have been a mess in xlc;
// currently version 13.1.5 is required.

static inline SimdFloat gmx_simdcall simdLoad(const float* m, SimdFloatTag = {})
{
    return { *reinterpret_cast<const __vector float*>(m) };
}

static inline void gmx_simdcall store(float* m, SimdFloat a)
{
    *reinterpret_cast<__vector float*>(m) = a.simdInternal_;
}

static inline SimdFloat gmx_simdcall simdLoadU(const float* m, SimdFloatTag = {})
{
    return
    {
#if __GNUC__ < 7
        *reinterpret_cast<const __vector float*>(m)
#else
        vec_xl(0, m)
#endif
    };
}

static inline void gmx_simdcall storeU(float* m, SimdFloat a)
{
#if __GNUC__ < 7
    *reinterpret_cast<__vector float*>(m) = a.simdInternal_;
#else
    vec_xst(a.simdInternal_, 0, m);
#endif
}

static inline SimdFloat gmx_simdcall setZeroF()
{
    return { vec_splats(0.0F) };
}

static inline SimdFInt32 gmx_simdcall simdLoad(const std::int32_t* m, SimdFInt32Tag)
{
    return { *reinterpret_cast<const __vector int*>(m) };
}

static inline void gmx_simdcall store(std::int32_t* m, SimdFInt32 a)
{
    *reinterpret_cast<__vector int*>(m) = a.simdInternal_;
}

static inline SimdFInt32 gmx_simdcall simdLoadU(const std::int32_t* m, SimdFInt32Tag)
{
    return
    {
#if __GNUC__ < 7
        *reinterpret_cast<const __vector int*>(m)
#else
        vec_xl(0, m)
#endif
    };
}

static inline void gmx_simdcall storeU(std::int32_t* m, SimdFInt32 a)
{
#if __GNUC__ < 7
    *reinterpret_cast<__vector int*>(m) = a.simdInternal_;
#else
    vec_xst(a.simdInternal_, 0, m);
#endif
}

static inline SimdFInt32 gmx_simdcall setZeroFI()
{
    return { vec_splats(static_cast<int>(0)) };
}

// gcc-4.9 does not detect that vec_extract() uses its argument
template<int index>
static inline std::int32_t gmx_simdcall extract(SimdFInt32 gmx_unused a)
{
    return vec_extract(a.simdInternal_, index);
}

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

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

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

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

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

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

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

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

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

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

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

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

static inline SimdFloat gmx_simdcall rsqrt(SimdFloat x)
{
    return { vec_rsqrte(x.simdInternal_) };
}

static inline SimdFloat gmx_simdcall rcp(SimdFloat x)
{
    return { vec_re(x.simdInternal_) };
}

static inline SimdFloat gmx_simdcall maskAdd(SimdFloat a, SimdFloat b, SimdFBool m)
{
    return { vec_add(a.simdInternal_,
                     vec_and(b.simdInternal_, reinterpret_cast<__vector float>(m.simdInternal_))) };
}

static inline SimdFloat gmx_simdcall maskzMul(SimdFloat a, SimdFloat b, SimdFBool m)
{
    SimdFloat prod = a * b;

    return { vec_and(prod.simdInternal_, reinterpret_cast<__vector float>(m.simdInternal_)) };
}

static inline SimdFloat gmx_simdcall maskzFma(SimdFloat a, SimdFloat b, SimdFloat c, SimdFBool m)
{
    SimdFloat prod = fma(a, b, c);

    return { vec_and(prod.simdInternal_, reinterpret_cast<__vector float>(m.simdInternal_)) };
}

static inline SimdFloat gmx_simdcall maskzRsqrt(SimdFloat x, SimdFBool m)
{
#ifndef NDEBUG
    x.simdInternal_ = vec_sel(vec_splats(1.0F), x.simdInternal_, m.simdInternal_);
#endif
    return { vec_and(vec_rsqrte(x.simdInternal_), reinterpret_cast<__vector float>(m.simdInternal_)) };
}

static inline SimdFloat gmx_simdcall maskzRcp(SimdFloat x, SimdFBool m)
{
#ifndef NDEBUG
    x.simdInternal_ = vec_sel(vec_splats(1.0F), x.simdInternal_, m.simdInternal_);
#endif
    return { vec_and(vec_re(x.simdInternal_), reinterpret_cast<__vector float>(m.simdInternal_)) };
}

static inline SimdFloat gmx_simdcall abs(SimdFloat x)
{
    return { vec_abs(x.simdInternal_) };
}

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

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

static inline SimdFloat gmx_simdcall round(SimdFloat x)
{
    return { vec_round(x.simdInternal_) };
}

static inline SimdFloat gmx_simdcall trunc(SimdFloat x)
{
    return { vec_trunc(x.simdInternal_) };
}

template<MathOptimization opt = MathOptimization::Safe>
static inline SimdFloat gmx_simdcall frexp(SimdFloat value, SimdFInt32* exponent)
{
    const __vector float exponentMask = reinterpret_cast<__vector float>(vec_splats(0x7F800000U));
    const __vector signed int exponentBias = vec_splats(126);
    const __vector float      half         = vec_splats(0.5F);
    __vector signed int       iExponent;

    __vector vsxBool int valueIsZero =
            vec_cmpeq(value.simdInternal_, reinterpret_cast<__vector float>(vec_splats(0.0)));

    iExponent = reinterpret_cast<__vector signed int>(vec_and(value.simdInternal_, exponentMask));
    iExponent = vec_sub(vec_sr(iExponent, vec_splats(23U)), exponentBias);
    iExponent = vec_andc(iExponent, reinterpret_cast<__vector int>(valueIsZero));

    __vector float result = vec_or(vec_andc(value.simdInternal_, exponentMask), half);
    result                = vec_sel(result, value.simdInternal_, valueIsZero);

    exponent->simdInternal_ = iExponent;

    return { result };
}

template<MathOptimization opt = MathOptimization::Safe>
static inline SimdFloat gmx_simdcall ldexp(SimdFloat value, SimdFInt32 exponent)
{
    const __vector signed int exponentBias = vec_splats(127);
    __vector signed int       iExponent;

    iExponent = vec_add(exponent.simdInternal_, exponentBias);

    if (opt == MathOptimization::Safe)
    {
        // Make sure biased argument is not negative
        iExponent = vec_max(iExponent, vec_splat_s32(0));
    }

    iExponent = vec_sl(iExponent, vec_splats(23U));

    return { vec_mul(value.simdInternal_, reinterpret_cast<__vector float>(iExponent)) };
}

static inline float gmx_simdcall reduce(SimdFloat x)
{
    const __vector unsigned char perm1 = { 8, 9, 10, 11, 12, 13, 14, 15, 0, 1, 2, 3, 4, 5, 6, 7 };
    const __vector unsigned char perm2 = { 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3 };

    x.simdInternal_ = vec_add(x.simdInternal_, vec_perm(x.simdInternal_, x.simdInternal_, perm1));
    x.simdInternal_ = vec_add(x.simdInternal_, vec_perm(x.simdInternal_, x.simdInternal_, perm2));
    return vec_extract(x.simdInternal_, 0);
}

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

static inline SimdFBool gmx_simdcall operator!=(SimdFloat a, SimdFloat b)
{
    return { vec_or(vec_cmpgt(a.simdInternal_, b.simdInternal_),
                    vec_cmplt(a.simdInternal_, b.simdInternal_)) };
}

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

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

static inline SimdFBool gmx_simdcall testBits(SimdFloat a)
{
    return { vec_cmpgt(reinterpret_cast<__vector unsigned int>(a.simdInternal_), vec_splats(0U)) };
}

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

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

static inline bool gmx_simdcall anyTrue(SimdFBool a)
{
    return vec_any_ne(a.simdInternal_, reinterpret_cast<__vector vsxBool int>(vec_splats(0)));
}

static inline SimdFloat gmx_simdcall selectByMask(SimdFloat a, SimdFBool m)
{
    return { vec_and(a.simdInternal_, reinterpret_cast<__vector float>(m.simdInternal_)) };
}

static inline SimdFloat gmx_simdcall selectByNotMask(SimdFloat a, SimdFBool m)
{
    return { vec_andc(a.simdInternal_, reinterpret_cast<__vector float>(m.simdInternal_)) };
}

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

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

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

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

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

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

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

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

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

static inline SimdFIBool gmx_simdcall testBits(SimdFInt32 a)
{
    return { vec_cmpgt(reinterpret_cast<__vector unsigned int>(a.simdInternal_), vec_splats(0U)) };
}

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

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

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

static inline bool gmx_simdcall anyTrue(SimdFIBool a)
{
    return vec_any_ne(a.simdInternal_, reinterpret_cast<__vector vsxBool int>(vec_splats(0)));
}

static inline SimdFInt32 gmx_simdcall selectByMask(SimdFInt32 a, SimdFIBool m)
{
    return { vec_and(a.simdInternal_, reinterpret_cast<__vector signed int>(m.simdInternal_)) };
}

static inline SimdFInt32 gmx_simdcall selectByNotMask(SimdFInt32 a, SimdFIBool m)
{
    return { vec_andc(a.simdInternal_, reinterpret_cast<__vector signed int>(m.simdInternal_)) };
}

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

static inline SimdFInt32 gmx_simdcall cvtR2I(SimdFloat a)
{
    return { vec_cts(vec_round(a.simdInternal_), 0) };
}

static inline SimdFInt32 gmx_simdcall cvttR2I(SimdFloat a)
{
    return { vec_cts(a.simdInternal_, 0) };
}

static inline SimdFloat gmx_simdcall cvtI2R(SimdFInt32 a)
{
    return { vec_ctf(a.simdInternal_, 0) };
}

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

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

static inline SimdFloat gmx_simdcall copysign(SimdFloat x, SimdFloat y)
{
#if defined(__GNUC__) && !defined(__ibmxl__) && !defined(__xlC__)
    __vector float res;
    __asm__("xvcpsgnsp %x0,%x1,%x2" : "=wf"(res) : "wf"(y.simdInternal_), "wf"(x.simdInternal_));
    return { res };
#else
    return { vec_cpsgn(y.simdInternal_, x.simdInternal_) };
#endif
}

} // namespace gmx

#endif // GMX_SIMD_IMPLEMENTATION_IBM_VSX_SIMD_FLOAT_H