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 #include "libm.h"
31
32 /* INDENT OFF */
33 /*
34 * float __k_sin(double x);
35 * kernel (float) sin function on [-pi/4, pi/4], pi/4 ~ 0.785398164
36 * Input x is in double and assumed to be bounded by ~pi/4 in magnitude.
37 *
38 * Method: Let z = x * x, then
39 * S(x) = x(S0 + S1*z)(S2 + S3*z + z*z)
40 * where
41 * S0 = 1.85735322054308378716204874632872525989806770558e-0003,
42 * S1 = -1.95035094218403635082921458859320791358115801259e-0004,
43 * S2 = 5.38400550766074785970952495168558701485841707252e+0002,
44 * S3 = -3.31975110777873728964197739157371509422022905947e+0001,
45 *
46 * The remez error is bound by |(sin(x) - S(x))/x| < 2**(-28.2)
47 *
48 * Constants:
49 * The hexadecimal values are the intended ones for the following constants.
50 * The decimal values may be used, provided that the compiler will convert
51 * from decimal to binary accurately enough to produce the hexadecimal values
52 * shown.
53 */
54 /* INDENT ON */
55
56 static const double q[] = {
57 /* S0 = */ 1.85735322054308378716204874632872525989806770558e-0003,
58 /* S1 = */ -1.95035094218403635082921458859320791358115801259e-0004,
59 /* S2 = */ 5.38400550766074785970952495168558701485841707252e+0002,
60 /* S3 = */ -3.31975110777873728964197739157371509422022905947e+0001,
61 };
62
63 #define S0 q[0]
64 #define S1 q[1]
65 #define S2 q[2]
66 #define S3 q[3]
67
68 float
__k_sinf(double x)69 __k_sinf(double x) {
70 float ft;
71 double z;
72 int hx;
73
74 hx = ((int *) &x)[HIWORD]; /* hx = leading x */
75 if ((hx & ~0x80000000) < 0x3f100000) { /* if |x| < 2**-14 */
76 ft = (float) x;
77 if ((int) x == 0) /* raise inexact if x != 0 */
78 return (ft);
79 }
80 z = x * x;
81 ft = (float) ((x * (S0 + z * S1)) * (S2 + z * (S3 + z)));
82 return (ft);
83 }
84