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 /*
31 * __rem_pio2l(x,y)
32 *
33 * return the remainder of x rem pi/2 in y[0]+y[1]
34 * by calling __rem_pio2m
35 */
36
37 #include "libm.h"
38 #include "longdouble.h"
39
40 extern const int _TBL_ipio2l_inf[];
41
42 static const long double
43 two24l = 16777216.0L,
44 pio4 = 0.7853981633974483096156608458198757210495L;
45
46 int
__rem_pio2l(long double x,long double * y)47 __rem_pio2l(long double x, long double *y)
48 {
49 long double z, w;
50 double t[3], v[5];
51 int e0, i, nx, n, sign;
52
53 sign = signbitl(x);
54 z = fabsl(x);
55 if (z <= pio4) {
56 y[0] = x;
57 y[1] = 0;
58 return (0);
59 }
60 e0 = ilogbl(z) - 23;
61 z = scalbnl(z, -e0);
62 for (i = 0; i < 3; i++) {
63 t[i] = (double)((int)(z));
64 z = (z - (long double)t[i]) * two24l;
65 }
66 nx = 3;
67 while (t[nx-1] == 0.0)
68 nx--; /* omit trailing zeros */
69 n = __rem_pio2m(t, v, e0, nx, 2, _TBL_ipio2l_inf);
70 z = (long double)v[1];
71 w = (long double)v[0];
72 y[0] = z + w;
73 y[1] = z - (y[0] - w);
74 if (sign != 0) {
75 y[0] = -y[0];
76 y[1] = -y[1];
77 return (-n);
78 }
79 return (n);
80 }
81