xref: /titanic_41/usr/src/lib/libm/common/Q/rndintl.c (revision dfa1896db444d8b104da7cb009f39f1a89a438aa)
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  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
23  */
24 /*
25  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
26  * Use is subject to license terms.
27  */
28 
29 /*
30  * aintl(x)	return x chopped to integral value
31  * anintl(x)	return sign(x)*(|x|+0.5) chopped to integral value
32  * irintl(x)	return rint(x) in integer format
33  * nintl(x)	return anint(x) in integer format
34  *
35  * NOTE: aintl(x), anintl(x), ceill(x), floorl(x), and rintl(x) return result
36  * with the same sign as x's,  including 0.0.
37  */
38 
39 #include "libm.h"
40 #include "longdouble.h"
41 
42 extern enum fp_direction_type __swapRD(enum fp_direction_type);
43 
44 static const long double qone = 1.0L, qhalf = 0.5L, qmhalf = -0.5L;
45 
46 long double
47 aintl(long double x) {
48 	long double t, w;
49 
50 	if (!finitel(x))
51 		return (x + x);
52 	w = fabsl(x);
53 	t = rintl(w);
54 	if (t <= w)
55 		return (copysignl(t, x));	/* NaN or already aint(|x|) */
56 	else	/* |t|>|x| case */
57 		return (copysignl(t - qone, x));	/* |t-1|*sign(x) */
58 }
59 
60 long double
61 anintl(long double x) {
62 	long double t, w, z;
63 
64 	if (!finitel(x))
65 		return (x + x);
66 	w = fabsl(x);
67 	t = rintl(w);
68 	if (t == w)
69 		return (copysignl(t, x));
70 	z = t - w;
71 	if (z > qhalf)
72 		t = t - qone;
73 	else if (z <= qmhalf)
74 		t = t + qone;
75 	return (copysignl(t, x));
76 }
77 
78 int
79 irintl(long double x) {
80 	enum fp_direction_type rd;
81 
82 	rd = __swapRD(fp_nearest);
83 	(void) __swapRD(rd);	/* restore Rounding Direction */
84 	switch (rd) {
85 	case fp_nearest:
86 		if (x < 2147483647.5L && x >= -2147483648.5L)
87 			return ((int)rintl(x));
88 		break;
89 	case fp_tozero:
90 		if (x < 2147483648.0L && x > -2147483649.0L)
91 			return ((int)rintl(x));
92 		break;
93 	case fp_positive:
94 		if (x <= 2147483647.0L && x > -2147483649.0L)
95 			return ((int)rintl(x));
96 		break;
97 	case fp_negative:
98 		if (x < 2147483648.0L && x >= -2147483648.0L)
99 			return ((int)rintl(x));
100 		break;
101 	}
102 	return ((int)copysignl(1.0e100L, x));
103 }
104 
105 int
106 nintl(long double x) {
107 	if ((x < 2147483647.5L) && (x > -2147483648.5L))
108 		return ((int)anintl(x));
109 	else
110 		return ((int)copysignl(1.0e100L, x));
111 }
112