1 /* Copyright (C) 2002 by Red Hat, Incorporated. All rights reserved.
2 *
3 * Permission to use, copy, modify, and distribute this software
4 * is freely granted, provided that this notice is preserved.
5 */
6 /*
7 FUNCTION
8 <<fdim>>, <<fdimf>>---positive difference
9 INDEX
10 fdim
11 INDEX
12 fdimf
13
14 SYNOPSIS
15 #include <math.h>
16 double fdim(double <[x]>, double <[y]>);
17 float fdimf(float <[x]>, float <[y]>);
18
19 DESCRIPTION
20 The <<fdim>> functions determine the positive difference between their
21 arguments, returning:
22 . <[x]> - <[y]> if <[x]> > <[y]>, or
23 @ifnottex
24 . +0 if <[x]> <= <[y]>, or
25 @end ifnottex
26 @tex
27 . +0 if <[x]> $\leq$ <[y]>, or
28 @end tex
29 . NAN if either argument is NAN.
30 A range error may occur.
31
32 RETURNS
33 The <<fdim>> functions return the positive difference value.
34
35 PORTABILITY
36 ANSI C, POSIX.
37
38 */
39
40 #include "fdlibm.h"
41
42 #ifdef _NEED_FLOAT64
43
44 __float64
fdim64(__float64 x,__float64 y)45 fdim64(__float64 x, __float64 y)
46 {
47 if (isnan(x) || isnan(y)) return(x+y);
48
49 __float64 z = x > y ? x - y : _F_64(0.0);
50 if (!isinf(x) && !isinf(y))
51 z = check_oflow(z);
52 return z;
53 }
54
55 _MATH_ALIAS_d_dd(fdim)
56
57 #endif /* _NEED_FLOAT64 */
58
