81 lines
1.4 KiB
C
81 lines
1.4 KiB
C
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/* @(#)z_fabs.c 1.0 98/08/13 */
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/*
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FUNCTION
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<<fabs>>, <<fabsf>>---absolute value (magnitude)
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INDEX
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fabs
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INDEX
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fabsf
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ANSI_SYNOPSIS
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#include <math.h>
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double fabs(double <[x]>);
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float fabsf(float <[x]>);
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TRAD_SYNOPSIS
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#include <math.h>
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double fabs(<[x]>)
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double <[x]>;
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float fabsf(<[x]>)
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float <[x]>;
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DESCRIPTION
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<<fabs>> and <<fabsf>> calculate
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@tex
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$|x|$,
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@end tex
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the absolute value (magnitude) of the argument <[x]>, by direct
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manipulation of the bit representation of <[x]>.
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RETURNS
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The calculated value is returned.
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PORTABILITY
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<<fabs>> is ANSI.
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<<fabsf>> is an extension.
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*/
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/******************************************************************
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* Floating-Point Absolute Value
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*
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* Input:
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* x - floating-point number
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*
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* Output:
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* absolute value of x
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*
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* Description:
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* fabs computes the absolute value of a floating point number.
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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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#ifndef _DOUBLE_IS_32BITS
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double
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_DEFUN (fabs, (double),
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double x)
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{
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switch (numtest (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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errno = ERANGE;
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return (x);
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case 0:
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return (0.0);
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default:
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return (x < 0.0 ? -x : x);
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}
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}
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#endif /* _DOUBLE_IS_32BITS */
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