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46 lines
857 B
C
46 lines
857 B
C
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/* @(#)z_atanf.c 1.0 98/08/13 */
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/******************************************************************
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* Arctangent
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*
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* Input:
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* x - floating point value
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*
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* Output:
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* arctan of x
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*
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* Description:
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* This routine returns the arctan of x.
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*
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*****************************************************************/
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#include "fdlibm.h"
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#include "zmath.h"
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float
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_DEFUN (atanf, (float),
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float x)
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{
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switch (numtestf (x))
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{
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case NAN:
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errno = EDOM;
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return (x);
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case INF:
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/* this should check to see if neg NaN or pos NaN... */
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return (__PI_OVER_TWO);
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case 0:
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return (0.0);
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default:
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return (atangentf (x, 0, 0, 0));
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}
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}
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#ifdef _DOUBLE_IS_32BITS
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double atan (double x)
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{
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return (double) atangentf ((float) x, 0, 0, 0);
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}
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#endif /* defined(_DOUBLE_IS_32BITS) */
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