1 files changed, 74 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/ieee754/dbl-64/e_atanh.c b/REORG.TODO/sysdeps/ieee754/dbl-64/e_atanh.c
new file mode 100644
index 0000000000..a9d19a0472
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+++ b/REORG.TODO/sysdeps/ieee754/dbl-64/e_atanh.c
@@ -0,0 +1,74 @@
+/* Copyright (C) 2011-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+
+/* __ieee754_atanh(x)
+   Method :
+      1.Reduced x to positive by atanh(-x) = -atanh(x)
+      2.For x>=0.5
+		    1              2x                          x
+	atanh(x) = --- * log(1 + -------) = 0.5 * log1p(2 * --------)
+		    2             1 - x                      1 - x
+
+	For x<0.5
+	atanh(x) = 0.5*log1p(2x+2x*x/(1-x))
+
+   Special cases:
+	atanh(x) is NaN if |x| > 1 with signal;
+	atanh(NaN) is that NaN with no signal;
+	atanh(+-1) is +-INF with signal.
+
+ */
+
+#include <float.h>
+#include <inttypes.h>
+#include <math.h>
+#include <math_private.h>
+
+static const double huge = 1e300;
+
+double
+__ieee754_atanh (double x)
+{
+  double xa = fabs (x);
+  double t;
+  if (isless (xa, 0.5))
+    {
+      if (__glibc_unlikely (xa < 0x1.0p-28))
+	{
+	  math_force_eval (huge + x);
+	  math_check_force_underflow (x);
+	  return x;
+	}
+
+      t = xa + xa;
+      t = 0.5 * __log1p (t + t * xa / (1.0 - xa));
+    }
+  else if (__glibc_likely (isless (xa, 1.0)))
+    t = 0.5 * __log1p ((xa + xa) / (1.0 - xa));
+  else
+    {
+      if (isgreater (xa, 1.0))
+	return (x - x) / (x - x);
+
+      return x / 0.0;
+    }
+
+  return __copysign (t, x);
+}
+strong_alias (__ieee754_atanh, __atanh_finite)