Import of the watch repository from Pebble

tests/libc/math/test_log.c

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <string.h>
+#include <stdio.h>
+#include <limits.h>
+#include <math.h>
+#include <fenv.h>
+
+#include "clar.h"
+
+double log_theirs(double x) {
+  return log(x);
+}
+
+// "Define" libc functions we're testing
+#include "pblibc_private.h"
+
+void test_pow__initialize(void) {
+  fesetround(FE_TONEAREST);
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+//! Tests
+
+void test_log__basic(void) {
+  for(int i = 1; i < 10000; i++) {
+    double v = i * 0.001;
+    double us = log(v);
+    double them = log_theirs(v);
+
+    // 1 ulps is acceptable error
+    // To actually check this, we need to do some sorta gross raw operations on the doubles
+    int64_t diff = *(int64_t*)&us - *(int64_t*)&them;
+    cl_assert(diff <= 1 && diff >= -1);
+  }
+  cl_assert(isnan(log(-1.0)));
+  cl_assert(log(0) == -HUGE_VAL);
+  cl_assert(isnan(log(NAN)));
+  cl_assert(isinf(log(INFINITY)));
+}