newlib-cygwin/newlib/libm/mathfp/sf_atan.c

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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, 0, 0);
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}
#endif /* defined(_DOUBLE_IS_32BITS) */