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/* Copyright (C) 2002 by  Red Hat, Incorporated. All rights reserved.

 *

 * Permission to use, copy, modify, and distribute this software

 * is freely granted, provided that this notice is preserved.

 */

/*

FUNCTION

<<fdim>>, <<fdimf>>--positive difference

INDEX

        fdim

INDEX

        fdimf

ANSI_SYNOPSIS

        #include <math.h>

        double fdim(double <[x]>, double <[y]>);

        float fdimf(float <[x]>, float <[y]>);

DESCRIPTION

The <<fdim>> functions determine the positive difference between their

arguments, returning:

.       <[x]> - <[y]>   if <[x]> > <[y]>, or

        @ifnottex

.       +0      if <[x]> <= <[y]>, or

        @end ifnottex

        @tex

.       +0      if <[x]> $\leq$ <[y]>, or

        @end tex

.       NAN     if either argument is NAN.

A range error may occur.

RETURNS

The <<fdim>> functions return the positive difference value.

PORTABILITY

ANSI C, POSIX.

*/

#include "fdlibm.h"

#ifndef _DOUBLE_IS_32BITS

#ifdef __STDC__

        double fdim(double x, double y)

#else

        double fdim(x,y)

        double x;

        double y;

#endif

{

  int c = __fpclassifyd(x);

  if (c == FP_NAN)  return(x);

  if (__fpclassifyd(y) == FP_NAN)  return(y);

  if (c == FP_INFINITE)

    return HUGE_VAL;

  return x > y ? x - y : 0.0;

}

#endif /* _DOUBLE_IS_32BITS */