Sk4f: add floor()

tests/SkNxTest.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Sk4px.h"
 #include "SkNx.h"
 #include "SkRandom.h"
@@ skipping 197 matching lines @@
 }
 
 DEF_TEST(SkNx_abs, r) {
     auto fs = Sk4f(0.0f, -0.0f, 2.0f, -4.0f).abs();
     REPORTER_ASSERT(r, fs.kth<0>() == 0.0f);
     REPORTER_ASSERT(r, fs.kth<1>() == 0.0f);
     REPORTER_ASSERT(r, fs.kth<2>() == 2.0f);
     REPORTER_ASSERT(r, fs.kth<3>() == 4.0f);
 }
 
+DEF_TEST(SkNx_floor, r) {
+    auto fs = Sk4f(0.4f, -0.4f, 0.6f, -0.6f).floor();
+    REPORTER_ASSERT(r, fs.kth<0>() ==  0.0f);
+    REPORTER_ASSERT(r, fs.kth<1>() == -1.0f);
+    REPORTER_ASSERT(r, fs.kth<2>() ==  0.0f);
+    REPORTER_ASSERT(r, fs.kth<3>() == -1.0f);
+}
+
 DEF_TEST(SkNx_shuffle, r) {
     Sk4f f4(0,10,20,30);
 
     Sk2f f2 = SkNx_shuffle<2,1>(f4);
     REPORTER_ASSERT(r, f2[0] == 20);
     REPORTER_ASSERT(r, f2[1] == 10);
 
     f4 = SkNx_shuffle<0,1,1,0>(f2);
     REPORTER_ASSERT(r, f4[0] == 20);
     REPORTER_ASSERT(r, f4[1] == 10);
@@ skipping 32 matching lines @@
             (uint16_t)rand.nextU16(), (uint16_t)rand.nextU16(),
         };
         auto u4_0 = Sk4h::Load(s16);
         auto f4 = SkNx_cast<float>(u4_0);
         auto u4_1 = SkNx_cast<uint16_t>(f4);
         uint16_t d16[4];
         u4_1.store(d16);
         REPORTER_ASSERT(r, !memcmp(s16, d16, sizeof(s16)));
     }
 }