Import of the watch repository from Pebble

third_party/jerryscript/jerry-libm/ceil.c

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+/* Copyright 2016 Samsung Electronics Co., Ltd.
+ * Copyright 2016 University of Szeged
+ *
+ * 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.
+ *
+ * This file is based on work under the following copyright and permission
+ * notice:
+ *
+ *     Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ *     Developed at SunSoft, a Sun Microsystems, Inc. business.
+ *     Permission to use, copy, modify, and distribute this
+ *     software is freely granted, provided that this notice
+ *     is preserved.
+ *
+ *     @(#)s_ceil.c 1.3 95/01/18
+ */
+
+#include "jerry-libm-internal.h"
+
+/* ceil(x)
+ * Return x rounded toward -inf to integral value
+ *
+ * Method:
+ *      Bit twiddling.
+ *
+ * Exception:
+ *      Inexact flag raised if x not equal to ceil(x).
+ */
+
+#define huge 1.0e300
+
+double
+ceil (double x)
+{
+  int i0, i1, j0;
+  unsigned i, j;
+
+  i0 = __HI (x);
+  i1 = __LO (x);
+  j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
+  if (j0 < 20)
+  {
+    if (j0 < 0) /* raise inexact if x != 0 */
+    {
+      if (huge + x > 0.0) /* return 0 * sign(x) if |x| < 1 */
+      {
+        if (i0 < 0)
+        {
+          i0 = 0x80000000;
+          i1 = 0;
+        }
+        else if ((i0 | i1) != 0)
+        {
+          i0 = 0x3ff00000;
+          i1 = 0;
+        }
+      }
+    }
+    else
+    {
+      i = (0x000fffff) >> j0;
+      if (((i0 & i) | i1) == 0) /* x is integral */
+      {
+        return x;
+      }
+      if (huge + x > 0.0) /* raise inexact flag */
+      {
+        if (i0 > 0)
+        {
+          i0 += (0x00100000) >> j0;
+        }
+        i0 &= (~i);
+        i1 = 0;
+      }
+    }
+  }
+  else if (j0 > 51)
+  {
+    if (j0 == 0x400) /* inf or NaN */
+    {
+      return x + x;
+    }
+    else /* x is integral */
+    {
+      return x;
+    }
+  }
+  else
+  {
+    i = ((unsigned) (0xffffffff)) >> (j0 - 20);
+    if ((i1 & i) == 0) /* x is integral */
+    {
+      return x;
+    }
+    if (huge + x > 0.0) /* raise inexact flag */
+    {
+      if (i0 > 0)
+      {
+        if (j0 == 20)
+        {
+          i0 += 1;
+        }
+        else
+        {
+          j = i1 + (1 << (52 - j0));
+          if (j < i1) /* got a carry */
+          {
+            i0 += 1;
+          }
+          i1 = j;
+        }
+      }
+      i1 &= (~i);
+    }
+  }
+  __HI (x) = i0;
+  __LO (x) = i1;
+  return x;
+} /* ceil */
+
+#undef huge