xref: /illumos-gate/usr/src/lib/libc/port/fp/finite.c (revision 1da57d55)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 /*	IEEE recommended functions */
31 
32 #pragma weak _finite = finite
33 #pragma weak _fpclass = fpclass
34 #pragma weak _unordered = unordered
35 
36 #include "lint.h"
37 #include <values.h>
38 #include "fpparts.h"
39 
40 #define	P754_NOFAULT 1		/* avoid generating extra code */
41 #include <ieeefp.h>
42 
43 /*
44  * FINITE(X)
45  * finite(x) returns 1 if x > -inf and x < +inf and 0 otherwise
46  * NaN returns 0
47  */
48 
49 int
finite(double x)50 finite(double x)
51 {
52 	return ((EXPONENT(x) != MAXEXP));
53 }
54 
55 /*
56  * UNORDERED(x,y)
57  * unordered(x,y) returns 1 if x is unordered with y, otherwise
58  * it returns 0; x is unordered with y if either x or y is NAN
59  */
60 
61 int
unordered(double x,double y)62 unordered(double x, double y)
63 {
64 	if ((EXPONENT(x) == MAXEXP) && (HIFRACTION(x) || LOFRACTION(x)))
65 		return (1);
66 	if ((EXPONENT(y) == MAXEXP) && (HIFRACTION(y) || LOFRACTION(y)))
67 		return (1);
68 	return (0);
69 }
70 
71 /*
72  * FPCLASS(X)
73  * fpclass(x) returns the floating point class x belongs to
74  */
75 
76 fpclass_t
fpclass(double x)77 fpclass(double x)
78 {
79 	int	sign, exp;
80 
81 	exp = EXPONENT(x);
82 	sign = SIGNBIT(x);
83 	if (exp == 0) { /* de-normal or zero */
84 		if (HIFRACTION(x) || LOFRACTION(x)) /* de-normal */
85 			return (sign ? FP_NDENORM : FP_PDENORM);
86 		else
87 			return (sign ? FP_NZERO : FP_PZERO);
88 	}
89 	if (exp == MAXEXP) { /* infinity or NaN */
90 		if ((HIFRACTION(x) == 0) && (LOFRACTION(x) == 0)) /* infinity */
91 			return (sign ? FP_NINF : FP_PINF);
92 		else
93 			if (QNANBIT(x))
94 			/* hi-bit of mantissa set - quiet nan */
95 				return (FP_QNAN);
96 			else	return (FP_SNAN);
97 	}
98 	/* if we reach here we have non-zero normalized number */
99 	return (sign ? FP_NNORM : FP_PNORM);
100 }
101