| |
| /* @(#)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); |
| } |
| |
| #endif /* defined(_DOUBLE_IS_32BITS) */ |