1 files changed, 91 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/s_tanhl.c b/sysdeps/libm-ieee754/s_tanhl.c
new file mode 100644
index 0000000000..984f67108b
--- /dev/null
+++ b/sysdeps/libm-ieee754/s_tanhl.c
@@ -0,0 +1,91 @@
+/* s_tanhl.c -- long double version of s_tanh.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
+
+/* tanhl(x)
+ * Return the Hyperbolic Tangent of x
+ *
+ * Method :
+ *				        x    -x
+ *				       e  - e
+ *	0. tanhl(x) is defined to be -----------
+ *				        x    -x
+ *				       e  + e
+ *	1. reduce x to non-negative by tanhl(-x) = -tanhl(x).
+ *	2.  0      <= x <= 2**-55 : tanhl(x) := x*(one+x)
+ *					         -t
+ *	    2**-55 <  x <=  1     : tanhl(x) := -----; t = expm1l(-2x)
+ *					        t + 2
+ *						      2
+ *	    1      <= x <=  23.0  : tanhl(x) := 1-  ----- ; t=expm1l(2x)
+ *						    t + 2
+ *	    23.0   <  x <= INF    : tanhl(x) := 1.
+ *
+ * Special cases:
+ *	tanhl(NaN) is NaN;
+ *	only tanhl(0)=0 is exact for finite argument.
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static const long double one=1.0, two=2.0, tiny = 1.0e-16380L;
+#else
+static long double one=1.0, two=2.0, tiny = 1.0e-16380L;
+#endif
+
+#ifdef __STDC__
+	long double __tanhl(long double x)
+#else
+	long double __tanhl(x)
+	long double x;
+#endif
+{
+	long double t,z;
+	int32_t se,j0,j1,ix;
+
+    /* High word of |x|. */
+	GET_LDOUBLE_WORDS(se,j0,j1,x);
+	ix = se&0x7fff;
+
+    /* x is INF or NaN */
+	if(ix==0x7fff) {
+	    if (se>=0x7fff) return one/x+one;    /* tanhl(+-inf)=+-1 */
+	    else            return one/x-one;    /* tanhl(NaN) = NaN */
+	}
+
+    /* |x| < 23 */
+	if (ix < 0x4003 || (ix == 0x4003 && j0 < 0xb8000000)) {	/* |x|<23 */
+	    if (ix<0x3fc8) 		/* |x|<2**-55 */
+		return x*(one+x);    	/* tanh(small) = small */
+	    if (ix>=0x3fff) {	/* |x|>=1  */
+		t = __expm1l(two*fabsl(x));
+		z = one - two/(t+two);
+	    } else {
+	        t = __expm1l(-two*fabsl(x));
+	        z= -t/(t+two);
+	    }
+    /* |x| > 23, return +-1 */
+	} else {
+	    z = one - tiny;		/* raised inexact flag */
+	}
+	return (se>0x7fff)? z: -z;
+}
+weak_alias (__tanhl, tanhl)