de-proc sk_float_rsqrt

src/opts/SkFloatingPoint_opts.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.
- */
-
-#ifndef SkFloatingPoint_opts_DEFINED
-#define SkFloatingPoint_opts_DEFINED
-
-#include "SkFloatingPoint.h"
-
-namespace SK_OPTS_NS {
-
-#if defined(SK_ARM_HAS_NEON)
-    static float rsqrt(float x) {
-        return sk_float_rsqrt(x);  // This sk_float_rsqrt copy will take the NEON compile-time path.
-    }
-#else
-    static float rsqrt(float x) {
-        // Get initial estimate.
-        int i = *SkTCast<int*>(&x);
-        i = 0x5F1FFFF9 - (i>>1);
-        float estimate = *SkTCast<float*>(&i);
-
-        // One step of Newton's method to refine.
-        const float estimate_sq = estimate*estimate;
-        estimate *= 0.703952253f*(2.38924456f-x*estimate_sq);
-        return estimate;
-    }
-#endif
-
-}  // namespace SK_OPTS_NS
-
-#endif//SkFloatingPoint_opts_DEFINED