1 files changed, 104 insertions, 0 deletions
diff --git a/newlib/libm/mathfp/sf_tan.c b/newlib/libm/mathfp/sf_tan.c
new file mode 100644
index 00000000000..fcde19ab3d4
--- /dev/null
+++ b/newlib/libm/mathfp/sf_tan.c
@@ -0,0 +1,104 @@
+
+/* @(#)z_tanf.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.
+ ******************************************************************/
+/******************************************************************
+ * Tangent
+ *
+ * Input:
+ *   x - floating point value
+ *
+ * Output:
+ *   tangent of x
+ *
+ * Description:
+ *   This routine calculates the tangent of x.
+ *
+ *****************************************************************/
+
+#include "fdlibm.h"
+#include "zmath.h"
+
+static const float TWO_OVER_PI = 0.6366197723;
+static const float p[] = { -0.958017723e-1 };
+static const float q[] = { -0.429135777,
+                            0.971685835e-2 };
+
+float
+_DEFUN (tanf, (float),
+        float x)
+{
+  float y, f, g, XN, xnum, xden, res;
+  int N;
+
+  /* Check for special values. */
+  switch (numtestf (x))
+    {
+      case NAN:
+        errno = EDOM;
+        return (x);
+      case INF:
+        errno = EDOM;
+        return (z_notanum_f.f);
+    }
+
+  y = fabsf (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 = (float) N;
+
+  f = x - N * __PI_OVER_TWO;
+
+  /* Check for values that are too small. */
+  if (-z_rooteps_f < f && f < z_rooteps_f)
+    {
+      xnum = f;
+      xden = 1.0;
+    }
+
+  /* Calculate the polynomial. */ 
+  else
+    { 
+      g = f * f;
+
+      xnum = f * (p[0] * g) + f;
+      xden = (q[1] * g + q[0]) * g + 1.0;
+    }
+
+  /* Check for odd or even values. */
+  if (N & 1)
+    {
+      xnum = -xnum;
+      res = xden / xnum;
+    } 
+  else
+    {
+      res = xnum / xden;
+    }
+
+  return (res);
+}
+
+#ifdef _DOUBLE_IS_32BITS
+
+double tan (double x)
+{
+  return (double) tanf ((float) x);
+}
+
+#endif /* _DOUBLE_IS_32BITS */