1 files changed, 139 insertions, 0 deletions
diff --git a/newlib/libm/mathfp/s_tan.c b/newlib/libm/mathfp/s_tan.c
new file mode 100644
index 00000000000..725aeec265d
--- /dev/null
+++ b/newlib/libm/mathfp/s_tan.c
@@ -0,0 +1,139 @@
+
+/* @(#)z_tan.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
+        <<tan>>, <<tanf>>---tangent
+
+INDEX
+tan
+INDEX
+tanf
+
+ANSI_SYNOPSIS
+        #include <math.h>
+        double tan(double <[x]>);
+        float tanf(float <[x]>);
+
+TRAD_SYNOPSIS
+        #include <math.h>
+        double tan(<[x]>)
+        double <[x]>;
+
+        float tanf(<[x]>)
+        float <[x]>;
+
+
+DESCRIPTION
+<<tan>> computes the tangent of the argument <[x]>.
+Angles are specified in radians.
+
+<<tanf>> is identical, save that it takes and returns <<float>> values.
+
+RETURNS
+The tangent of <[x]> is returned.
+
+PORTABILITY
+<<tan>> is ANSI. <<tanf>> is an extension.
+*/
+
+/******************************************************************
+ * Tangent
+ *
+ * Input:
+ *   x - floating point value
+ *
+ * Output:
+ *   tangent of x
+ *
+ * Description:
+ *   This routine calculates the tangent of x.
+ *
+ *****************************************************************/
+
+#include "fdlibm.h"
+#include "zmath.h"
+
+#ifndef _DOUBLE_IS_32BITS
+
+static const double TWO_OVER_PI = 0.63661977236758134308;
+static const double p[] = { -0.13338350006421960681,
+                             0.34248878235890589960e-2,
+                            -0.17861707342254426711e-4 };
+static const double q[] = { -0.46671683339755294240,
+                             0.25663832289440112864e-1,
+                            -0.31181531907010027307e-3,
+                             0.49819433993786512270e-6 };
+
+double
+_DEFUN (tan, (double),
+        double x)
+{
+  double y, f, g, XN, xnum, xden, res;
+  int N;
+
+  /* Check for special values. */
+  switch (numtest (x))
+    {
+      case NAN:
+        errno = EDOM;
+        return (x);
+      case INF:
+        errno = EDOM;
+        return (z_notanum.d);
+    }
+
+  y = fabs (x);
+
+  /* Check for values that are out of our range. */
+  if (y > 105414357.0)
+    {
+      errno = ERANGE;
+      return (y);
+    }
+
+  if (x < 0.0)
+    N = (int) (x * TWO_OVER_PI - 0.5);
+  else
+    N = (int) (x * TWO_OVER_PI + 0.5);
+
+  XN = (double) N;
+
+  f = x - N * __PI_OVER_TWO;
+
+  /* Check for values that are too small. */
+  if (-z_rooteps < f && f < z_rooteps)
+    {
+      xnum = f;
+      xden = 1.0;
+    }
+
+  /* Calculate the polynomial. */ 
+  else
+    { 
+      g = f * f;
+
+      xnum = f * ((p[2] * g + p[1]) * g + p[0]) * g + f;
+      xden = (((q[3] * g + q[2]) * g + q[1]) * g + q[0]) * g + 1.0;
+    }
+
+  if (N & 1)
+    {
+      xnum = -xnum;
+      res = xden / xnum;
+    } 
+  else
+    {
+      res = xnum / xden;
+    }
+
+  return (res);
+}
+
+#endif /* _DOUBLE_IS_32BITS */