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 modfl = __modfl
32 #endif
33
34 #include "libm.h"
35
36 #if defined(__sparc)
37
38 long double
39 __modfl(long double x, long double *iptr) {
40 union {
41 unsigned i[4];
42 long double q;
43 } xx, yy;
44 unsigned hx, s;
45
46 xx.q = x;
47 hx = xx.i[0] & ~0x80000000;
48
49 if (hx >= 0x406f0000) { /* x is NaN, infinite, or integral */
50 *iptr = x;
51 if (hx < 0x7fff0000 || (hx == 0x7fff0000 &&
52 (xx.i[1] | xx.i[2] | xx.i[3]) == 0)) {
53 xx.i[0] &= 0x80000000;
54 xx.i[1] = xx.i[2] = xx.i[3] = 0;
55 }
56 return (xx.q);
57 }
58
59 if (hx < 0x3fff0000) { /* |x| < 1 */
60 xx.i[0] &= 0x80000000;
61 xx.i[1] = xx.i[2] = xx.i[3] = 0;
62 *iptr = xx.q;
63 return (x);
64 }
65
66 /* split x at the binary point */
67 s = xx.i[0] & 0x80000000;
68 if (hx < 0x40100000) {
69 yy.i[0] = xx.i[0] & ~((1 << (0x400f - (hx >> 16))) - 1);
70 yy.i[1] = yy.i[2] = yy.i[3] = 0;
71 } else if (hx < 0x40300000) {
72 yy.i[0] = xx.i[0];
73 yy.i[1] = xx.i[1] & ~((1 << (0x402f - (hx >> 16))) - 1);
74 yy.i[2] = yy.i[3] = 0;
75 } else if (hx < 0x40500000) {
76 yy.i[0] = xx.i[0];
77 yy.i[1] = xx.i[1];
78 yy.i[2] = xx.i[2] & ~((1 << (0x404f - (hx >> 16))) - 1);
79 yy.i[3] = 0;
80 } else {
81 yy.i[0] = xx.i[0];
82 yy.i[1] = xx.i[1];
83 yy.i[2] = xx.i[2];
84 yy.i[3] = xx.i[3] & ~((1 << (0x406f - (hx >> 16))) - 1);
85 }
86 *iptr = yy.q;
87
88 /*
89 * we could implement the following more efficiently than by using
90 * software emulation of fsubq, but we'll do it this way for now
91 * (and hope hardware support becomes commonplace)
92 */
93 xx.q -= yy.q;
94 xx.i[0] = (xx.i[0] & ~0x80000000) | s; /* keep sign of x */
95 return (xx.q);
96 }
97
98 #elif defined(__x86)
99
100 long double
101 __modfl(long double x, long double *iptr) {
102 union {
103 unsigned i[3];
104 long double e;
105 } xx, yy;
106 unsigned hx, s;
107
108 /*
109 * It might be faster to use one of the x86 fpops instead of
110 * the following.
111 */
112 xx.e = x;
113 hx = xx.i[2] & 0x7fff;
114
115 if (hx >= 0x403e) { /* x is NaN, infinite, or integral */
116 *iptr = x;
117 if (hx < 0x7fff || (hx == 0x7fff &&
118 ((xx.i[1] << 1) | xx.i[0]) == 0)) {
119 xx.i[2] &= 0x8000;
120 xx.i[1] = xx.i[0] = 0;
121 }
122 return (xx.e);
123 }
124
125 if (hx < 0x3fff) { /* |x| < 1 */
126 xx.i[2] &= 0x8000;
127 xx.i[1] = xx.i[0] = 0;
128 *iptr = xx.e;
129 return (x);
130 }
131
132 /* split x at the binary point */
133 s = xx.i[2] & 0x8000;
134 yy.i[2] = xx.i[2];
135 if (hx < 0x401f) {
136 yy.i[1] = xx.i[1] & ~((1 << (0x401e - hx)) - 1);
137 yy.i[0] = 0;
138 } else {
139 yy.i[1] = xx.i[1];
140 yy.i[0] = xx.i[0] & ~((1 << (0x403e - hx)) - 1);
141 }
142 *iptr = yy.e;
143 xx.e -= yy.e;
144 xx.i[2] = (xx.i[2] & ~0x8000) | s; /* keep sign of x */
145 return (xx.e);
146 }
147
148 #else
149 #error Unknown architecture
150 #endif