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 #pragma weak modf = __modf
31 #pragma weak _modf = __modf
32
33 /*
34 * modf(x, iptr) decomposes x into an integral part and a fractional
35 * part both having the same sign as x. It stores the integral part
36 * in *iptr and returns the fractional part.
37 *
38 * If x is infinite, modf sets *iptr to x and returns copysign(0.0,x).
39 * If x is NaN, modf sets *iptr to x and returns x.
40 *
41 * If x is a signaling NaN, this code does not attempt to raise the
42 * invalid operation exception.
43 */
44
45 #include "libm.h"
46
47 double
__modf(double x,double * iptr)48 __modf(double x, double *iptr) {
49 union {
50 unsigned i[2];
51 double d;
52 } xx, yy;
53 unsigned hx, s;
54
55 xx.d = x;
56 hx = xx.i[HIWORD] & ~0x80000000;
57
58 if (hx >= 0x43300000) { /* x is NaN, infinite, or integral */
59 *iptr = x;
60 if (hx < 0x7ff00000 || (hx == 0x7ff00000 &&
61 xx.i[LOWORD] == 0)) {
62 xx.i[HIWORD] &= 0x80000000;
63 xx.i[LOWORD] = 0;
64 }
65 return (xx.d);
66 }
67
68 if (hx < 0x3ff00000) { /* |x| < 1 */
69 xx.i[HIWORD] &= 0x80000000;
70 xx.i[LOWORD] = 0;
71 *iptr = xx.d;
72 return (x);
73 }
74
75 /* split x at the binary point */
76 s = xx.i[HIWORD] & 0x80000000;
77 if (hx < 0x41400000) {
78 yy.i[HIWORD] = xx.i[HIWORD] & ~((1 << (0x413 - (hx >> 20))) -
79 1);
80 yy.i[LOWORD] = 0;
81 } else {
82 yy.i[HIWORD] = xx.i[HIWORD];
83 yy.i[LOWORD] = xx.i[LOWORD] & ~((1 << (0x433 - (hx >> 20))) -
84 1);
85 }
86 *iptr = yy.d;
87 xx.d -= yy.d;
88 xx.i[HIWORD] = (xx.i[HIWORD] & ~0x80000000) | s;
89 /* keep sign of x */
90 return (xx.d);
91 }
92