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/* @(#)z_atanf.c 1.0 98/08/13 */

/******************************************************************

 * Arctangent

 *

 * Input:

 *   x - floating point value

 *

 * Output:

 *   arctan of x

 *

 * Description:

 *   This routine returns the arctan of x.

 *

 *****************************************************************/

#include "fdlibm.h"

#include "zmath.h"

float

_DEFUN (atanf, (float),

        float x)

{

  switch (numtestf (x))

    {

      case NAN:

        errno = EDOM;

        return (x);

      case INF:

        /* this should check to see if neg NaN or pos NaN... */

        return (__PI_OVER_TWO);

      case 0:

        return (0.0);

      default:

        return (atangentf (x, 0, 0, 0));

    }

}

#ifdef _DOUBLE_IS_32BITS

double atan (double x)

{

  return (double) atangentf ((float) x, 0);

}

#endif /* defined(_DOUBLE_IS_32BITS) */