Sk4px: Difference and Exclusion

src/opts/Sk4px_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.
  */
 
 inline Sk4px::Sk4px(SkPMColor px) : INHERITED((uint8x16_t)vdupq_n_u32(px)) {}
 
 inline Sk4px Sk4px::Load4(const SkPMColor px[4]) {
@@ skipping 60 matching lines @@
 
 inline Sk4px Sk4px::Load2Alphas(const SkAlpha a[2]) {
     uint8x16_t a8 = vdupq_n_u8(0);                        // ____ ____ ____ ____
     a8 = vld1q_lane_u8(a+0, a8,  0);                      // ____ ____ ____ ___0
     a8 = vld1q_lane_u8(a+1, a8,  4);                      // ____ ____ ___1 ___0
     auto a32 = (uint32x4_t)a8;                            //
     a32 = vorrq_u32(a32, vshlq_n_u32(a32,  8));           // ____ ____ __11 __00
     a32 = vorrq_u32(a32, vshlq_n_u32(a32, 16));           // ____ ____ 1111 0000
     return Sk16b((uint8x16_t)a32);
 }
+
+inline Sk4px Sk4px::zeroColors() const {
+    return Sk16b(vandq_u8(this->fVec, (uint8x16_t)vdupq_n_u32(0xFF << SK_A32_SHIFT)));
+}
+
+inline Sk4px Sk4px::zeroAlphas() const {
+    // vbic(a,b) == a & ~b
+    return Sk16b(vbicq_u8(this->fVec, (uint8x16_t)vdupq_n_u32(0xFF << SK_A32_SHIFT)));
+}
+