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 2011 Nexenta Systems, Inc. All rights reserved.
24 */
25 /*
26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
27 * Use is subject to license terms.
28 */
29
30 #if defined(ELFOBJ)
31 #pragma weak roundl = __roundl
32 #endif
33
34 #include "libm.h"
35
36 #if defined(__sparc)
37 long double
38 roundl(long double x) {
39 union {
40 unsigned i[4];
41 long double q;
42 } xx;
43 unsigned hx, sx, v;
44 int j;
45
46 xx.q = x;
47 sx = xx.i[0] & 0x80000000;
48 hx = xx.i[0] & ~0x80000000;
49
50 /* handle trivial cases */
51 if (hx >= 0x406f0000) /* |x| >= 2^112 + ... or x is nan */
52 return (hx >= 0x7fff0000 ? x + x : x);
53
54 /* handle |x| < 1 */
55 if (hx < 0x3fff0000) {
56 if (hx >= 0x3ffe0000)
57 return (sx ? -1.0L : 1.0L);
58 return (sx ? -0.0L : 0.0L);
59 }
60
61 xx.i[0] = hx;
62 j = 0x406f - (hx >> 16); /* 1 <= j <= 112 */
63 if (j >= 96) { /* 96 <= j <= 112 */
64 v = (1U << (j - 96)) >> 1;
65 if (v) {
66 if (xx.i[0] & v)
67 xx.i[0] += v;
68 xx.i[0] &= ~(v - 1);
69 } else if (xx.i[1] & 0x80000000)
70 ++xx.i[0];
71 xx.i[1] = xx.i[2] = xx.i[3] = 0;
72 } else if (j >= 64) { /* 64 <= j <= 95 */
73 v = (1U << (j - 64)) >> 1;
74 if (v) {
75 if (xx.i[1] & v) {
76 xx.i[1] += v;
77 if (xx.i[1] < v)
78 ++xx.i[0];
79 }
80 xx.i[1] &= ~(v - 1);
81 } else if (xx.i[2] & 0x80000000) {
82 if (++xx.i[1] == 0)
83 ++xx.i[0];
84 }
85 xx.i[2] = xx.i[3] = 0;
86 } else if (j >= 32) { /* 32 <= j <= 63 */
87 v = (1U << (j - 32)) >> 1;
88 if (v) {
89 if (xx.i[2] & v) {
90 xx.i[2] += v;
91 if (xx.i[2] < v) {
92 if (++xx.i[1] == 0)
93 ++xx.i[0];
94 }
95 }
96 xx.i[2] &= ~(v - 1);
97 } else if (xx.i[3] & 0x80000000) {
98 if (++xx.i[2] == 0) {
99 if (++xx.i[1] == 0)
100 ++xx.i[0];
101 }
102 }
103 xx.i[3] = 0;
104 } else { /* 1 <= j <= 31 */
105 v = 1U << (j - 1);
106 if (xx.i[3] & v) {
107 xx.i[3] += v;
108 if (xx.i[3] < v) {
109 if (++xx.i[2] == 0) {
110 if (++xx.i[1] == 0)
111 ++xx.i[0];
112 }
113 }
114 }
115 xx.i[3] &= ~(v - 1);
116 }
117
118 /* negate result if need be */
119 if (sx)
120 xx.i[0] |= 0x80000000;
121 return (xx.q);
122 }
123 #elif defined(__x86)
124 long double
125 roundl(long double x) {
126 union {
127 unsigned i[3];
128 long double e;
129 } xx;
130 int ex, sx, i;
131
132 xx.e = x;
133 ex = xx.i[2] & 0x7fff;
134 sx = xx.i[2] & 0x8000;
135 if (ex < 0x403e) { /* |x| < 2^63 */
136 if (ex < 0x3fff) { /* |x| < 1 */
137 if (ex >= 0x3ffe)
138 return (sx ? -1.0L : 1.0L);
139 return (sx ? -0.0L : 0.0L);
140 }
141
142 /* round x at the integer bit */
143 if (ex < 0x401e) {
144 i = 1 << (0x401d - ex);
145 xx.i[1] = (xx.i[1] + i) & ~(i | (i - 1));
146 xx.i[0] = 0;
147 } else {
148 i = 1 << (0x403d - ex);
149 xx.i[0] += i;
150 if (xx.i[0] < i)
151 xx.i[1]++;
152 xx.i[0] &= ~(i | (i - 1));
153 }
154 if (xx.i[1] == 0) {
155 xx.i[2] = sx | ++ex;
156 xx.i[1] = 0x80000000U;
157 }
158 return (xx.e);
159 } else if (ex < 0x7fff) /* x is integral */
160 return (x);
161 else /* inf or nan */
162 return (x + x);
163 }
164 #else
165 #error Unknown architecture
166 #endif /* defined(__sparc) || defined(__x86) */