src/opts/Sk4x_neon.h

// It is important _not_ to put header guards here.
// This file will be intentionally included three times.

#include "SkTypes.h"  // Keep this before any #ifdef for skbug.com/3362

#if defined(SK4X_PREAMBLE)
    #include <arm_neon.h>

    // Template metaprogramming to map scalar types to vector types.
    template <typename T> struct SkScalarToSIMD;
    template <> struct SkScalarToSIMD<float>   { typedef float32x4_t  Type; };
    template <> struct SkScalarToSIMD<int32_t> { typedef int32x4_t Type; };

#elif defined(SK4X_PRIVATE)
    Sk4x(float32x4_t);
    Sk4x(int32x4_t);

    typename SkScalarToSIMD<T>::Type fVec;

#else

// Vector Constructors
//template <> inline Sk4f::Sk4x(int32x4_t v) : fVec(vcvtq_f32_s32(v)) {}
template <> inline Sk4f::Sk4x(float32x4_t v) : fVec(v) {}
template <> inline Sk4i::Sk4x(int32x4_t v) : fVec(v) {}
//template <> inline Sk4i::Sk4x(float32x4_t v) : fVec(vcvtq_s32_f32(v)) {}

// Generic Methods
template <typename T> Sk4x<T>::Sk4x() {}
template <typename T> Sk4x<T>::Sk4x(const Sk4x& other) { *this = other; }
template <typename T> Sk4x<T>& Sk4x<T>::operator=(const Sk4x<T>& other) {
    fVec = other.fVec;
    return *this;
}

// Sk4f Methods
#define M(...) template <> inline __VA_ARGS__ Sk4f::

M() Sk4x(float v) : fVec(vdupq_n_f32(v)) {}
M() Sk4x(float a, float b, float c, float d) { fVec = (float32x4_t) { a, b, c, d }; }

// As far as I can tell, it's not possible to provide an alignment hint to
// NEON using intrinsics.  However, I think it is possible at the assembly
// level if we want to get into that.
// TODO: Write our own aligned load and store.
M(Sk4f) Load       (const float fs[4]) { return vld1q_f32(fs); }
M(Sk4f) LoadAligned(const float fs[4]) { return vld1q_f32(fs); }
M(void) store       (float fs[4]) const { vst1q_f32(fs, fVec); }
M(void) storeAligned(float fs[4]) const { vst1q_f32 (fs, fVec); }

template <>
M(Sk4i) reinterpret<Sk4i>() const { return vreinterpretq_s32_f32(fVec); }

template <>
M(Sk4i) cast<Sk4i>() const { return vcvtq_s32_f32(fVec); }

// We're going to skip allTrue(), anyTrue(), and bit-manipulators
// for Sk4f.  Code that calls them probably does so accidentally.
// Ask msarett or mtklein to fill these in if you really need them.
M(Sk4f) add     (const Sk4f& o) const { return vaddq_f32(fVec, o.fVec); }
M(Sk4f) subtract(const Sk4f& o) const { return vsubq_f32(fVec, o.fVec); }
M(Sk4f) multiply(const Sk4f& o) const { return vmulq_f32(fVec, o.fVec); }

M(Sk4f) divide  (const Sk4f& o) const {
#if defined(SK_CPU_ARM64)
    return vdivq_f32(fVec, o.fVec);
#else
    float32x4_t est0 = vrecpeq_f32(o.fVec),
                est1 = vmulq_f32(vrecpsq_f32(est0, o.fVec), est0),
                est2 = vmulq_f32(vrecpsq_f32(est1, o.fVec), est1);
    return vmulq_f32(est2, fVec);
#endif
}

M(Sk4f) rsqrt() const {
    float32x4_t est0 = vrsqrteq_f32(fVec),
                est1 = vmulq_f32(vrsqrtsq_f32(fVec, vmulq_f32(est0, est0)), est0);
    return est1;
}

M(Sk4f)  sqrt() const {
#if defined(SK_CPU_ARM64)
    return vsqrtq_f32(fVec);
#else
    float32x4_t est1 = this->rsqrt().fVec,
    // An extra step of Newton's method to refine the estimate of 1/sqrt(this).
                est2 = vmulq_f32(vrsqrtsq_f32(fVec, vmulq_f32(est1, est1)), est1);
    return vmulq_f32(fVec, est2);
#endif
}

M(Sk4i) equal           (const Sk4f& o) const { return vreinterpretq_s32_u32(vceqq_f32(fVec, o.fVec)); }
M(Sk4i) notEqual        (const Sk4f& o) const { return vreinterpretq_s32_u32(vmvnq_u32(vceqq_f32(fVec, o.fVec))); }
M(Sk4i) lessThan        (const Sk4f& o) const { return vreinterpretq_s32_u32(vcltq_f32(fVec, o.fVec)); }
M(Sk4i) greaterThan     (const Sk4f& o) const { return vreinterpretq_s32_u32(vcgtq_f32(fVec, o.fVec)); }
M(Sk4i) lessThanEqual   (const Sk4f& o) const { return vreinterpretq_s32_u32(vcleq_f32(fVec, o.fVec)); }
M(Sk4i) greaterThanEqual(const Sk4f& o) const { return vreinterpretq_s32_u32(vcgeq_f32(fVec, o.fVec)); }

M(Sk4f) Min(const Sk4f& a, const Sk4f& b) { return vminq_f32(a.fVec, b.fVec); }
M(Sk4f) Max(const Sk4f& a, const Sk4f& b) { return vmaxq_f32(a.fVec, b.fVec); }

M(Sk4f) badc() const { return vrev64q_f32(fVec); }

// Sk4i Methods
#undef M
#define M(...) template <> inline __VA_ARGS__ Sk4i::

M() Sk4x(int32_t v) : fVec(vdupq_n_s32(v)) {}
M() Sk4x(int32_t a, int32_t b, int32_t c, int32_t d) { fVec = (int32x4_t) { a, b, c, d }; }

// As far as I can tell, it's not possible to provide an alignment hint to
// NEON using intrinsics.  However, I think it is possible at the assembly
// level if we want to get into that.
M(Sk4i) Load       (const int32_t is[4]) { return vld1q_s32(is); }
M(Sk4i) LoadAligned(const int32_t is[4]) { return vld1q_s32(is); }
M(void) store       (int32_t is[4]) const { vst1q_s32(is, fVec); }
M(void) storeAligned(int32_t is[4]) const { vst1q_s32 (is, fVec); }

template <>
M(Sk4f) reinterpret<Sk4f>() const { return vreinterpretq_f32_s32(fVec); }

template <>
M(Sk4f) cast<Sk4f>() const { return vcvtq_f32_s32(fVec); }

M(bool) allTrue() const {
    int32_t a = vgetq_lane_s32(fVec, 0);
    int32_t b = vgetq_lane_s32(fVec, 1);
    int32_t c = vgetq_lane_s32(fVec, 2);
    int32_t d = vgetq_lane_s32(fVec, 3);
    return a & b & c & d;
}
M(bool) anyTrue() const {
    int32_t a = vgetq_lane_s32(fVec, 0);
    int32_t b = vgetq_lane_s32(fVec, 1);
    int32_t c = vgetq_lane_s32(fVec, 2);
    int32_t d = vgetq_lane_s32(fVec, 3);
    return a | b | c | d;
}

M(Sk4i) bitNot() const { return vmvnq_s32(fVec); }
M(Sk4i) bitAnd(const Sk4i& o) const { return vandq_s32(fVec, o.fVec); }
M(Sk4i) bitOr (const Sk4i& o) const { return vorrq_s32(fVec, o.fVec); }

M(Sk4i) equal           (const Sk4i& o) const { return vreinterpretq_s32_u32(vceqq_s32(fVec, o.fVec)); }
M(Sk4i) notEqual        (const Sk4i& o) const { return vreinterpretq_s32_u32(vmvnq_u32(vceqq_s32(fVec, o.fVec))); }
M(Sk4i) lessThan        (const Sk4i& o) const { return vreinterpretq_s32_u32(vcltq_s32(fVec, o.fVec)); }
M(Sk4i) greaterThan     (const Sk4i& o) const { return vreinterpretq_s32_u32(vcgtq_s32(fVec, o.fVec)); }
M(Sk4i) lessThanEqual   (const Sk4i& o) const { return vreinterpretq_s32_u32(vcleq_s32(fVec, o.fVec)); }
M(Sk4i) greaterThanEqual(const Sk4i& o) const { return vreinterpretq_s32_u32(vcgeq_s32(fVec, o.fVec)); }

M(Sk4i) add     (const Sk4i& o) const { return vaddq_s32(fVec, o.fVec); }
M(Sk4i) subtract(const Sk4i& o) const { return vsubq_s32(fVec, o.fVec); }
M(Sk4i) multiply(const Sk4i& o) const { return vmulq_s32(fVec, o.fVec); }
// NEON does not have integer reciprocal, sqrt, or division.
M(Sk4i) Min(const Sk4i& a, const Sk4i& b) { return vminq_s32(a.fVec, b.fVec); }
M(Sk4i) Max(const Sk4i& a, const Sk4i& b) { return vmaxq_s32(a.fVec, b.fVec); }

M(Sk4i) badc() const { return vrev64q_s32(fVec); }

#undef M

#endif