1 files changed, 84 insertions, 0 deletions
diff --git a/sysdeps/ieee754/ldbl-128/e_atanhl.c b/sysdeps/ieee754/ldbl-128/e_atanhl.c
new file mode 100644
index 0000000000..dd681c847c
--- /dev/null
+++ b/sysdeps/ieee754/ldbl-128/e_atanhl.c
@@ -0,0 +1,84 @@
+/* s_atanhl.c -- long double version of s_atan.c.
+ * Conversion to long double by Ulrich Drepper,
+ * Cygnus Support, drepper@cygnus.com.
+ */
+
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+#if defined(LIBM_SCCS) && !defined(lint)
+static char rcsid[] = "$NetBSD: $";
+#endif
+
+/* __ieee754_atanhl(x)
+ * Method :
+ *    1.Reduced x to positive by atanh(-x) = -atanh(x)
+ *    2.For x>=0.5
+ *                   1              2x                          x
+ *	atanhl(x) = --- * log(1 + -------) = 0.5 * log1p(2 * --------)
+ *                   2             1 - x                      1 - x
+ *
+ * 	For x<0.5
+ *	atanhl(x) = 0.5*log1pl(2x+2x*x/(1-x))
+ *
+ * Special cases:
+ *	atanhl(x) is NaN if |x| > 1 with signal;
+ *	atanhl(NaN) is that NaN with no signal;
+ *	atanhl(+-1) is +-INF with signal.
+ *
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static const long double one = 1.0L, huge = 1e4900L;
+#else
+static long double one = 1.0L, huge = 1e4900L;
+#endif
+
+#ifdef __STDC__
+static const long double zero = 0.0L;
+#else
+static double long zero = 0.0L;
+#endif
+
+#ifdef __STDC__
+	long double __ieee754_atanhl(long double x)
+#else
+	long double __ieee754_atanhl(x)
+	long double x;
+#endif
+{
+	long double t;
+	u_int32_t jx, ix;
+	ieee854_long_double_shape_type u;
+
+	u.value = x;
+	jx = u.parts32.w0;
+	ix = jx & 0x7fffffff;
+	u.parts32.w0 = ix;
+	if (ix >= 0x3fff0000) /* |x| >= 1.0 or infinity or NaN */
+	  {
+	    if (u.value == one)
+	      return x/zero;
+	    else
+	      return (x-x)/(x-x);
+	  }
+	if(ix<0x3fc60000 && (huge+x)>zero) return x;	/* x < 2^-57 */
+
+	if(ix<0x3ffe0000) {		/* x < 0.5 */
+	    t = u.value+u.value;
+	    t = 0.5*__log1pl(t+t*u.value/(one-u.value));
+	} else
+	    t = 0.5*__log1pl((u.value+u.value)/(one-u.value));
+	if(jx & 0x80000000) return -t; else return t;
+}