1 files changed, 129 insertions, 0 deletions
diff --git a/libm/ldouble/tanhl.c b/libm/ldouble/tanhl.c
new file mode 100644
index 000000000..42c7133c3
--- /dev/null
+++ b/libm/ldouble/tanhl.c
@@ -0,0 +1,129 @@
+/*							tanhl.c
+ *
+ *	Hyperbolic tangent, long double precision
+ *
+ *
+ *
+ * SYNOPSIS:
+ *
+ * long double x, y, tanhl();
+ *
+ * y = tanhl( x );
+ *
+ *
+ *
+ * DESCRIPTION:
+ *
+ * Returns hyperbolic tangent of argument in the range MINLOGL to
+ * MAXLOGL.
+ *
+ * A rational function is used for |x| < 0.625.  The form
+ * x + x**3 P(x)/Q(x) of Cody _& Waite is employed.
+ * Otherwise,
+ *    tanh(x) = sinh(x)/cosh(x) = 1  -  2/(exp(2x) + 1).
+ *
+ *
+ *
+ * ACCURACY:
+ *
+ *                      Relative error:
+ * arithmetic   domain     # trials      peak         rms
+ *    IEEE      -2,2        30000       1.3e-19     2.4e-20
+ *
+ */
+
+/*
+Cephes Math Library Release 2.7:  May, 1998
+Copyright 1984, 1987, 1989, 1998 by Stephen L. Moshier
+*/
+
+#include <math.h>
+
+#ifdef UNK
+static long double P[] = {
+-6.8473739392677100872869E-5L,
+-9.5658283111794641589011E-1L,
+-8.4053568599672284488465E1L,
+-1.3080425704712825945553E3L,
+};
+static long double Q[] = {
+/* 1.0000000000000000000000E0L,*/
+ 9.6259501838840336946872E1L,
+ 1.8218117903645559060232E3L,
+ 3.9241277114138477845780E3L,
+};
+#endif
+
+#ifdef IBMPC
+static short P[] = {
+0xd2a4,0x1b0c,0x8f15,0x8f99,0xbff1, XPD
+0x5959,0x9111,0x9cc7,0xf4e2,0xbffe, XPD
+0xb576,0xef5e,0x6d57,0xa81b,0xc005, XPD
+0xe3be,0xbfbd,0x5cbc,0xa381,0xc009, XPD
+};
+static short Q[] = {
+/*0x0000,0x0000,0x0000,0x8000,0x3fff,*/
+0x687f,0xce24,0xdd6c,0xc084,0x4005, XPD
+0x3793,0xc95f,0xfa2f,0xe3b9,0x4009, XPD
+0xd5a2,0x1f9c,0x0b1b,0xf542,0x400a, XPD
+};
+#endif
+
+#ifdef MIEEE
+static long P[] = {
+0xbff10000,0x8f998f15,0x1b0cd2a4,
+0xbffe0000,0xf4e29cc7,0x91115959,
+0xc0050000,0xa81b6d57,0xef5eb576,
+0xc0090000,0xa3815cbc,0xbfbde3be,
+};
+static long Q[] = {
+/*0x3fff0000,0x80000000,0x00000000,*/
+0x40050000,0xc084dd6c,0xce24687f,
+0x40090000,0xe3b9fa2f,0xc95f3793,
+0x400a0000,0xf5420b1b,0x1f9cd5a2,
+};
+#endif
+
+extern long double MAXLOGL;
+#ifdef ANSIPROT
+extern long double fabsl ( long double );
+extern long double expl ( long double );
+extern long double polevll ( long double, void *, int );
+extern long double p1evll ( long double, void *, int );
+#else
+long double fabsl(), expl(), polevll(), p1evll();
+#endif
+
+long double tanhl(x)
+long double x;
+{
+long double s, z;
+
+#ifdef MINUSZERO
+if( x == 0.0L )
+	return(x);
+#endif
+z = fabsl(x);
+if( z > 0.5L * MAXLOGL )
+	{
+	if( x > 0 )
+		return( 1.0L );
+	else
+		return( -1.0L );
+	}
+if( z >= 0.625L )
+	{
+	s = expl(2.0*z);
+	z =  1.0L  - 2.0/(s + 1.0L);
+	if( x < 0 )
+		z = -z;
+	}
+else
+	{
+	s = x * x;
+	z = polevll( s, P, 3 )/p1evll(s, Q, 3);
+	z = x * s * z;
+	z = x + z;
+	}
+return( z );
+}