4x library for NEON

tests/Sk4xTest.cpp

Index: tests/Sk4xTest.cpp
diff --git a/tests/Sk4xTest.cpp b/tests/Sk4xTest.cpp
index 23eaf6853e6bc7ddab62b44f1be51bd1b01f5a51..7c49dd8137bfdcb909dd62e62e5680e534a6922d 100644
--- a/tests/Sk4xTest.cpp
+++ b/tests/Sk4xTest.cpp
@@ -75,8 +75,13 @@ DEF_TEST(Sk4x_Arith, r) {
     ASSERT_EQ(Sk4f(-2,-2,-2,-2), Sk4f(1,2,3,4).subtract(Sk4f(3,4,5,6)));
     ASSERT_EQ(Sk4f(3,8,15,24),   Sk4f(1,2,3,4).multiply(Sk4f(3,4,5,6)));
 
+    // NEON implements division as multiplication by a reciprocal estimate.
+    // It may have some error.
     float third = 1.0f/3.0f;
-    ASSERT_EQ(Sk4f(1*third, 0.5f, 0.6f, 2*third), Sk4f(1,2,3,4).divide(Sk4f(3,4,5,6)));
+    Sk4f quotients = Sk4f(1*third, 0.5f, 0.6f, 2*third);
+    Sk4f error = quotients.subtract(Sk4f(1,2,3,4).divide(Sk4f(3,4,5,6)));
+    REPORTER_ASSERT(r, error.greaterThan(-0.001f).allTrue());
+    REPORTER_ASSERT(r, error.lessThan(0.001f).allTrue());
 
     ASSERT_EQ(Sk4i(4,6,8,10),    Sk4i(1,2,3,4).add(Sk4i(3,4,5,6)));
     ASSERT_EQ(Sk4i(-2,-2,-2,-2), Sk4i(1,2,3,4).subtract(Sk4i(3,4,5,6)));
@@ -96,7 +101,7 @@ DEF_TEST(Sk4x_Sqrt, r) {
     // .rsqrt() isn't so precise, but should be pretty close.
     Sk4f error = roots.subtract(squares.multiply(squares.rsqrt()));
     REPORTER_ASSERT(r, error.greaterThan(0.0f).allTrue());
-    REPORTER_ASSERT(r, error.lessThan(0.01f).allTrue());
+    REPORTER_ASSERT(r, error.lessThan(0.011f).allTrue());
 }
 
 DEF_TEST(Sk4x_Comparison, r) {