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 /*
27 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
28 * Use is subject to license terms.
29 */
30
31 #pragma weak nearbyintl = __nearbyintl
32
33 #include "libm.h"
34 #include "fma.h"
35 #include "fenv_inlines.h"
36
37 #if defined(__sparc)
38 static union {
39 unsigned i;
40 float f;
41 } snan = { 0x7f800001 };
42 long double
43 __nearbyintl(long double x)
44 {
45 union {
46 unsigned i[4];
47 long double q;
48 } xx;
49
50 unsigned hx, sx, i, frac;
51 unsigned int fsr;
52 int rm, j;
53 volatile float dummy;
54
55 xx.q = x;
56 sx = xx.i[0] & 0x80000000;
57 hx = xx.i[0] & ~0x80000000;
58
59 /* handle trivial cases */
60 if (hx >= 0x406f0000) { /* x is nan, inf, or already integral */
61 /* check for signaling nan */
62 if ((hx > 0x7fff0000 || (hx == 0x7fff0000 && (xx.i[1] |
63 xx.i[2] | xx.i[3]))) && !(hx & 0x8000)) {
64 dummy = snan.f;
65 dummy += snan.f;
66 xx.i[0] = sx | hx | 0x8000;
67 }
68
69 return (xx.q);
70 } else if ((hx | xx.i[1] | xx.i[2] | xx.i[3]) == 0) { /* x is zero */
71 return (x);
72 }
73
74 /* get the rounding mode */
75 __fenv_getfsr32(&fsr);
76 rm = fsr >> 30;
77
78 /* flip the sense of directed roundings if x is negative */
79 if (sx)
80 rm ^= rm >> 1;
81
82 /* handle |x| < 1 */
83 if (hx < 0x3fff0000) {
84 if (rm == FSR_RP || (rm == FSR_RN && (hx >= 0x3ffe0000 && ((hx &
85 0xffff) | xx.i[1] | xx.i[2] | xx.i[3]))))
86 xx.i[0] = sx | 0x3fff0000;
87 else
88 xx.i[0] = sx;
89
90 xx.i[1] = xx.i[2] = xx.i[3] = 0;
91 return (xx.q);
92 }
93
94 /* round x at the integer bit */
95 j = 0x406f - (hx >> 16);
96
97 if (j >= 96) {
98 i = 1 << (j - 96);
99 frac = ((xx.i[0] << 1) << (127 - j)) | (xx.i[1] >> (j - 96));
100
101 if ((xx.i[1] & (i - 1)) | xx.i[2] | xx.i[3])
102 frac |= 1;
103
104 if (!frac)
105 return (x);
106
107 xx.i[1] = xx.i[2] = xx.i[3] = 0;
108 xx.i[0] &= ~(i - 1);
109
110 if (rm == FSR_RP || (rm == FSR_RN && (frac > 0x80000000u ||
111 (frac == 0x80000000 && (xx.i[0] & i)))))
112 xx.i[0] += i;
113 } else if (j >= 64) {
114 i = 1 << (j - 64);
115 frac = ((xx.i[1] << 1) << (95 - j)) | (xx.i[2] >> (j - 64));
116
117 if ((xx.i[2] & (i - 1)) | xx.i[3])
118 frac |= 1;
119
120 if (!frac)
121 return (x);
122
123 xx.i[2] = xx.i[3] = 0;
124 xx.i[1] &= ~(i - 1);
125
126 if (rm == FSR_RP || (rm == FSR_RN && (frac > 0x80000000u ||
127 (frac == 0x80000000 && (xx.i[1] & i))))) {
128 xx.i[1] += i;
129
130 if (xx.i[1] == 0)
131 xx.i[0]++;
132 }
133 } else if (j >= 32) {
134 i = 1 << (j - 32);
135 frac = ((xx.i[2] << 1) << (63 - j)) | (xx.i[3] >> (j - 32));
136
137 if (xx.i[3] & (i - 1))
138 frac |= 1;
139
140 if (!frac)
141 return (x);
142
143 xx.i[3] = 0;
144 xx.i[2] &= ~(i - 1);
145
146 if (rm == FSR_RP || (rm == FSR_RN && (frac > 0x80000000u ||
147 (frac == 0x80000000 && (xx.i[2] & i))))) {
148 xx.i[2] += i;
149
150 if (xx.i[2] == 0)
151 if (++xx.i[1] == 0)
152 xx.i[0]++;
153 }
154 } else {
155 i = 1 << j;
156 frac = (xx.i[3] << 1) << (31 - j);
157
158 if (!frac)
159 return (x);
160
161 xx.i[3] &= ~(i - 1);
162
163 if (rm == FSR_RP || (rm == FSR_RN && (frac > 0x80000000u ||
164 (frac == 0x80000000 && (xx.i[3] & i))))) {
165 xx.i[3] += i;
166
167 if (xx.i[3] == 0)
168 if (++xx.i[2] == 0)
169 if (++xx.i[1] == 0)
170 xx.i[0]++;
171 }
172 }
173
174 return (xx.q);
175 }
176 #elif defined(__x86)
177 /* inline template */
178 extern long double frndint(long double);
179 long double
180 __nearbyintl(long double x)
181 {
182 long double z;
183 unsigned oldcwsw, cwsw;
184
185 /* save the control and status words, mask the inexact exception */
186 __fenv_getcwsw(&oldcwsw);
187 cwsw = oldcwsw | 0x00200000;
188 __fenv_setcwsw(&cwsw);
189
190 z = frndint(x);
191
192 /*
193 * restore the control and status words, preserving all but the
194 * inexact flag
195 */
196 __fenv_getcwsw(&cwsw);
197 oldcwsw |= (cwsw & 0x1f);
198 __fenv_setcwsw(&oldcwsw);
199
200 return (z);
201 }
202 #else
203 #error Unknown architecture
204 #endif