add Min to SkNi, specialized for u8 and u16 on SSE and NEON

src/core/SkNx.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_DEFINED
 #define SkNx_DEFINED
 
@@ skipping 50 matching lines @@
         return SkNi(fLo.saturatedAdd(o.fLo), fHi.saturatedAdd(o.fHi));
     }
 
     SkNi operator + (const SkNi& o) const { return SkNi(fLo + o.fLo, fHi + o.fHi); }
     SkNi operator - (const SkNi& o) const { return SkNi(fLo - o.fLo, fHi - o.fHi); }
     SkNi operator * (const SkNi& o) const { return SkNi(fLo * o.fLo, fHi * o.fHi); }
 
     SkNi operator << (int bits) const { return SkNi(fLo << bits, fHi << bits); }
     SkNi operator >> (int bits) const { return SkNi(fLo >> bits, fHi >> bits); }
 
-    // TODO: comparisons, min, max?
+    static SkNi Min(const SkNi& a, const SkNi& b) {
+        return SkNi(SkNi<N/2, T>::Min(a.fLo, b.fLo), SkNi<N/2, T>::Min(a.fHi, b.fHi));
+    }
+
+    // TODO: comparisons, max?
 
     template <int k> T kth() const {
         SkASSERT(0 <= k && k < N);
         return k < N/2 ? fLo.template kth<k>() : fHi.template kth<k-N/2>();
     }
 
 protected:
     REQUIRE(0 == (N & (N-1)));
 
     SkNi<N/2, T> fLo, fHi;
@@ skipping 94 matching lines @@
         return SkNi(sum > fVal ? sum : (T)(~0));
     }
 
     SkNi operator + (const SkNi& o) const { return SkNi(fVal + o.fVal); }
     SkNi operator - (const SkNi& o) const { return SkNi(fVal - o.fVal); }
     SkNi operator * (const SkNi& o) const { return SkNi(fVal * o.fVal); }
 
     SkNi operator << (int bits) const { return SkNi(fVal << bits); }
     SkNi operator >> (int bits) const { return SkNi(fVal >> bits); }
 
+    static SkNi Min(const SkNi& a, const SkNi& b) { return SkNi(SkTMin(a.fVal, b.fVal)); }
+
     template <int k> T kth() const {
         SkASSERT(0 == k);
         return fVal;
     }
 
 protected:
     T fVal;
 };
 
 template <typename T>
@@ skipping 83 matching lines @@
 typedef SkNi<4,  uint16_t> Sk4h;
 typedef SkNi<8,  uint16_t> Sk8h;
 typedef SkNi<16, uint16_t> Sk16h;
 
 typedef SkNi<16, uint8_t> Sk16b;
 
 typedef SkNi<4,  int32_t> Sk4i;
 typedef SkNi<4, uint32_t> Sk4u;
 
 #endif//SkNx_DEFINED