Color dodge and burn with SkPMFloat.

src/opts/SkNx_sse.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 SkNx_sse_DEFINED
 #define SkNx_sse_DEFINED
 
@@ skipping 175 matching lines @@
 
     template <int k> float kth() const {
         SkASSERT(0 <= k && k < 4);
         union { __m128 v; float fs[4]; } pun = {fVec};
         return pun.fs[k&3];
     }
 
     bool allTrue() const { return 0xffff == _mm_movemask_epi8(_mm_castps_si128(fVec)); }
     bool anyTrue() const { return 0x0000 != _mm_movemask_epi8(_mm_castps_si128(fVec)); }
 
+    SkNf thenElse(const SkNf& t, const SkNf& e) const {
+        return _mm_or_ps(_mm_and_ps   (fVec, t.fVec),
+                         _mm_andnot_ps(fVec, e.fVec));
+    }
+
     __m128 fVec;
 };
 
 template <>
 class SkNi<4, uint16_t> {
 public:
     SkNi(const __m128i& vec) : fVec(vec) {}
 
     SkNi() {}
     explicit SkNi(uint16_t val) : fVec(_mm_set1_epi16(val)) {}
@@ skipping 93 matching lines @@
         return _mm_or_si128(_mm_and_si128   (fVec, t.fVec),
                             _mm_andnot_si128(fVec, e.fVec));
     }
 
     __m128i fVec;
 };
 
 }  // namespace
 
 #endif//SkNx_sse_DEFINED