Implement missing hyperbolic Math functions from ES6 (#3670)

Math.cosh, Math.sinh, Math.tanh C implementation ported from fdlibm. Part of Issue #3568 JerryScript-DCO-1.0-Signed-off-by: Rafal Walczyna r.walczyna@samsung.com
2020-04-21 12:34:38 +02:00
parent d1bf9635c7
commit bcd5ff3f40
11 changed files with 718 additions and 12 deletions
@@ -0,0 +1,113 @@
+/* Copyright JS Foundation and other contributors, http://js.foundation
+ *
+ * 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.
+ *
+ *     @(#)e_cosh.c 1.3 95/01/18
+ */
+
+#include "jerry-libm-internal.h"
+
+/* cosh(x)
+ * Method:
+ * mathematically cosh(x) if defined to be (exp(x) + exp(-x)) / 2
+ *  1. Replace x by |x| (cosh(x) = cosh(-x)).
+ *  2.
+ *                                                 [ exp(x) - 1 ]^2
+ *      0        <= x <= ln2/2  :  cosh(x) := 1 + -------------------
+ *                                                     2*exp(x)
+ *
+ *                                             exp(x) +  1/exp(x)
+ *      ln2/2    <= x <= 22     :  cosh(x) := -------------------
+ *                                                    2
+ *
+ *      22       <= x <= lnovft :  cosh(x) := exp(x)/2
+ *      lnovft   <= x <= ln2ovft:  cosh(x) := exp(x/2)/2 * exp(x/2)
+ *      ln2ovft  <  x           :  cosh(x) := huge * huge (overflow)
+ *
+ * Special cases:
+ *  cosh(x) is |x| if x is +INF, -INF, or NaN.
+ *  only cosh(0) = 1 is exact for finite x.
+ */
+
+#define one 1.0
+#define half 0.5
+#define huge 1.0e300
+
+double
+cosh (double x)
+{
+  double t, w;
+  int ix;
+  unsigned lx;
+
+  /* High word of |x|. */
+  ix = __HI (x);
+  ix &= 0x7fffffff;
+
+  /* x is INF or NaN */
+  if (ix >= 0x7ff00000)
+  {
+    return x * x;
+  }
+  /* |x| in [0, 0.5 * ln2], return 1 + expm1(|x|)^2 / (2 * exp(|x|)) */
+  if (ix < 0x3fd62e43)
+  {
+    t = expm1 (fabs (x));
+    w = one + t;
+    if (ix < 0x3c800000)
+    {
+      /* cosh(tiny) = 1 */
+      return w;
+    }
+    return one + (t * t) / (w + w);
+  }
+
+  /* |x| in [0.5 * ln2, 22], return (exp(|x|) + 1 / exp(|x|) / 2; */
+  if (ix < 0x40360000)
+  {
+    t = exp (fabs (x));
+    return half * t + half / t;
+  }
+
+  /* |x| in [22, log(maxdouble)] return half * exp(|x|) */
+  if (ix < 0x40862E42)
+  {
+    return half * exp (fabs (x));
+  }
+  /* |x| in [log(maxdouble), overflowthresold] */
+  lx = ((1 >> 29) + (unsigned int) x);
+  if ((ix < 0x408633CE) ||
+      ((ix == 0x408633ce) && (lx <= (unsigned) 0x8fb9f87d)))
+  {
+    w = exp (half * fabs (x));
+    t = half * w;
+    return t * w;
+  }
+
+  /* |x| > overflowthresold, cosh(x) overflow */
+  return huge * huge;
+} /* cosh */
+
+#undef one
+#undef half
+#undef huge