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