Sk2x for NEON

src/opts/Sk2x_neon.h

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+// 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(SK2X_PREAMBLE)
+    #include <arm_neon.h>
+    #include <math.h>
+    template <typename T> struct SkScalarToSIMD;
+    template <> struct SkScalarToSIMD< float> { typedef float32x2_t Type; };
+    template <> struct SkScalarToSIMD<double> { typedef double Type[2];   };
+
+
+#elif defined(SK2X_PRIVATE)
+    typename SkScalarToSIMD<T>::Type fVec;
+    /*implicit*/ Sk2x(const typename SkScalarToSIMD<T>::Type vec) { fVec = vec; }
+
+#else
+
+#define M(...) template <> inline __VA_ARGS__ Sk2x<float>::
+
+M() Sk2x() {}
+M() Sk2x(float val)        { fVec = vdup_n_f32(val);    }
+M() Sk2x(float a, float b) {
+    fVec = vset_lane_f32(a, fVec, 0);
+    fVec = vset_lane_f32(b, fVec, 1);
+}
+M(Sk2f&) operator=(const Sk2f& o) { fVec = o.fVec; return *this; }
+
+M(Sk2f) Load(const float vals[2]) { return vld1_f32(vals); }
+M(void) store(float vals[2]) const { vst1_f32(vals, fVec); }
+
+M(Sk2f)      add(const Sk2f& o) const { return vadd_f32(fVec, o.fVec); }
+M(Sk2f) subtract(const Sk2f& o) const { return vsub_f32(fVec, o.fVec); }
+M(Sk2f) multiply(const Sk2f& o) const { return vmul_f32(fVec, o.fVec); }
+
+M(Sk2f) Min(const Sk2f& a, const Sk2f& b) { return vmin_f32(a.fVec, b.fVec); }
+M(Sk2f) Max(const Sk2f& a, const Sk2f& b) { return vmax_f32(a.fVec, b.fVec); }
+
+M(Sk2f) rsqrt() const {
+    float32x2_t est0 = vrsqrte_f32(fVec),
+                est1 = vmul_f32(vrsqrts_f32(fVec, vmul_f32(est0, est0)), est0);
+    return est1;
+}
+M(Sk2f)  sqrt() const {
+    float32x2_t est1 = this->rsqrt().fVec,
+    // An extra step of Newton's method to refine the estimate of 1/sqrt(this).
+                est2 = vmul_f32(vrsqrts_f32(fVec, vmul_f32(est1, est1)), est1);
+    return vmul_f32(fVec, est2);
+}
+
+#undef M
+
+#define M(...) template <> inline __VA_ARGS__ Sk2x<double>::
+
+// TODO: #ifdef SK_CPU_ARM64 use float64x2_t for Sk2d.
+
+M() Sk2x() {}
+M() Sk2x(double val)         { fVec[0] = fVec[1] = val; }
+M() Sk2x(double a, double b) { fVec[0] = a; fVec[1] = b; }
+M(Sk2d&) operator=(const Sk2d& o) {
+    fVec[0] = o.fVec[0];
+    fVec[1] = o.fVec[1];
+    return *this;
+}
+
+M(Sk2d) Load(const double vals[2]) { return Sk2d(vals[0], vals[1]); }
+M(void) store(double vals[2]) const { vals[0] = fVec[0]; vals[1] = fVec[1]; }
+
+M(Sk2d)      add(const Sk2d& o) const { return Sk2d(fVec[0] + o.fVec[0], fVec[1] + o.fVec[1]); }
+M(Sk2d) subtract(const Sk2d& o) const { return Sk2d(fVec[0] - o.fVec[0], fVec[1] - o.fVec[1]); }
+M(Sk2d) multiply(const Sk2d& o) const { return Sk2d(fVec[0] * o.fVec[0], fVec[1] * o.fVec[1]); }
+
+M(Sk2d) Min(const Sk2d& a, const Sk2d& b) {
+    return Sk2d(SkTMin(a.fVec[0], b.fVec[0]), SkTMin(a.fVec[1], b.fVec[1]));
+}
+M(Sk2d) Max(const Sk2d& a, const Sk2d& b) {
+    return Sk2d(SkTMax(a.fVec[0], b.fVec[0]), SkTMax(a.fVec[1], b.fVec[1]));
+}
+
+M(Sk2d) rsqrt() const { return Sk2d(1.0/::sqrt(fVec[0]), 1.0/::sqrt(fVec[1])); }
+M(Sk2d)  sqrt() const { return Sk2d(    ::sqrt(fVec[0]),     ::sqrt(fVec[1])); }
+
+#undef M
+
+#endif