text: /* 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 */
  