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] by calling __rem_pio2m
34 */
35
36 #ifndef FDLIBM_BASED
37 #include "libm.h"
38 extern int __rem_pio2m(double *, double *, int, int, int, const int *);
39 #else /* FDLIBM_BASED */
40 #include "fdlibm.h"
41 #define __rem_pio2m __kernel_rem_pio2
42 #endif /* FDLIBM_BASED */
43
44 #include "longdouble.h"
45
46 extern const int _TBL_ipio2l_inf[];
47
48 static const long double
49 two24l = 16777216.0L,
50 pio4 = 0.7853981633974483096156608458198757210495L;
51
52 int
__rem_pio2l(long double x,long double * y)53 __rem_pio2l(long double x, long double *y)
54 {
55 long double z, w;
56 double t[5], v[5];
57 int e0, i, nx, n, sign;
58 const int *ipio2;
59
60 sign = signbitl(x);
61 z = fabsl(x);
62 if (z <= pio4) {
63 y[0] = x;
64 y[1] = 0;
65 return (0);
66 }
67 e0 = ilogbl(z) - 23;
68 z = scalbnl(z, -e0);
69 for (i = 0; i < 5; i++) {
70 t[i] = (double)((int)(z));
71 z = (z - (long double)t[i]) * two24l;
72 }
73 nx = 5;
74 while (t[nx - 1] == 0.0)
75 nx--; /* skip zero term */
76 ipio2 = _TBL_ipio2l_inf;
77 n = __rem_pio2m(t, v, e0, nx, 3, (const int *)ipio2);
78 z = (long double)v[2] + (long double)v[1];
79 w = (long double)v[0];
80 y[0] = z + w;
81 y[1] = z - (y[0] - w);
82 if (sign != 0) {
83 y[0] = -y[0];
84 y[1] = -y[1];
85 return (-n);
86 }
87 return (n);
88 }
89