1 files changed, 117 insertions, 0 deletions
diff --git a/newlib/libm/mathfp/s_tanh.c b/newlib/libm/mathfp/s_tanh.c
new file mode 100644
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+++ b/newlib/libm/mathfp/s_tanh.c
@@ -0,0 +1,117 @@
+
+/* @(#)z_tanh.c 1.0 98/08/13 */
+/*****************************************************************
+ * The following routines are coded directly from the algorithms
+ * and coefficients given in "Software Manual for the Elementary
+ * Functions" by William J. Cody, Jr. and William Waite, Prentice
+ * Hall, 1980.
+ *****************************************************************/
+
+/*
+
+FUNCTION
+        <<tanh>>, <<tanhf>>---hyperbolic tangent
+
+INDEX
+tanh
+INDEX
+tanhf
+
+ANSI_SYNOPSIS
+        #include <math.h>
+        double tanh(double <[x]>);
+        float tanhf(float <[x]>);
+
+TRAD_SYNOPSIS
+        #include <math.h>
+        double tanh(<[x]>)
+        double <[x]>;
+
+        float tanhf(<[x]>)
+        float <[x]>;
+
+
+DESCRIPTION
+
+<<tanh>> computes the hyperbolic tangent of
+the argument <[x]>.  Angles are specified in radians.
+
+<<tanh(<[x]>)>> is defined as
+. sinh(<[x]>)/cosh(<[x]>)
+
+<<tanhf>> is identical, save that it takes and returns <<float>> values.
+
+RETURNS
+The hyperbolic tangent of <[x]> is returned.
+
+PORTABILITY
+<<tanh>> is ANSI C.  <<tanhf>> is an extension.
+
+*/
+
+/******************************************************************
+ * Hyperbolic Tangent
+ *
+ * Input:
+ *   x - floating point value
+ *
+ * Output:
+ *   hyperbolic tangent of x
+ *
+ * Description:
+ *   This routine calculates hyperbolic tangent.
+ *
+ *****************************************************************/
+
+#include <float.h>
+#include "fdlibm.h"
+#include "zmath.h"
+
+#ifndef _DOUBLE_IS_32BITS
+
+static const double LN3_OVER2 = 0.54930614433405484570;
+static const double p[] = { -0.16134119023996228053e+4,
+                            -0.99225929672236083313e+2,
+                            -0.96437492777225469787 };
+static const double q[] = { 0.48402357071988688686e+4,
+                            0.22337720718962312926e+4,
+                            0.11274474380534949335e+3 }; 
+
+double
+_DEFUN (tanh, (double),
+        double x)
+{
+  double f, res, g, P, Q, R;
+
+  f = fabs (x);
+
+  /* Check if the input is too big. */ 
+  if (f > BIGX)
+    res = 1.0; 
+
+  else if (f > LN3_OVER2)
+    res = 1.0 - 2.0 / (exp (2 * f) + 1.0);
+
+  /* Check if the input is too small. */
+  else if (f < z_rooteps)
+    res = f;
+
+  /* Calculate the Taylor series. */
+  else
+    {
+      g = f * f;
+
+      P = (p[2] * g + p[1]) * g + p[0];
+      Q = ((g + q[2]) * g + q[1]) * g + q[0];
+      R = g * (P / Q);
+
+      res = f + f * R;
+    }
+
+  if (x < 0.0)
+    res = -res;
+
+  return (res);
+}
+
+#endif /* _DOUBLE_IS_32BITS */