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_tan(double x);
35 * kernel (float) tan 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 * Constants:
39 * The hexadecimal values are the intended ones for the following constants.
40 * The decimal values may be used, provided that the compiler will convert
41 * from decimal to binary accurately enough to produce the hexadecimal values
42 * shown.
43 */
44
45 static const double q[] = {
46 /* one */ 1.0,
47 /* P0 */ 4.46066928428959230679140546271810308098793029785e-0003,
48 /* P1 */ 4.92165316309189027066395283327437937259674072266e+0000,
49 /* P2 */ -7.11410648161473480044492134766187518835067749023e-0001,
50 /* P3 */ 4.08549808374053391446523164631798863410949707031e+0000,
51 /* P4 */ 2.50411070398050927821032018982805311679840087891e+0000,
52 /* P5 */ 1.11492064560251158411574579076841473579406738281e+0001,
53 /* P6 */ -1.50565540968422650891511693771462887525558471680e+0000,
54 /* P7 */ -1.81484378878349295050043110677506774663925170898e+0000,
55 /* T0 */ 3.333335997532835641297409611782510896641e-0001,
56 /* T1 */ 2.999997598248363761541668282006867229939e+00,
57 };
58 /* INDENT ON */
59
60 #define one q[0]
61 #define P0 q[1]
62 #define P1 q[2]
63 #define P2 q[3]
64 #define P3 q[4]
65 #define P4 q[5]
66 #define P5 q[6]
67 #define P6 q[7]
68 #define P7 q[8]
69 #define T0 q[9]
70 #define T1 q[10]
71
72 float
__k_tanf(double x,int n)73 __k_tanf(double x, int n) {
74 float ft = 0.0;
75 double z, w;
76 int ix;
77
78 ix = ((int *) &x)[HIWORD] & ~0x80000000; /* ix = leading |x| */
79 /* small argument */
80 if (ix < 0x3f800000) { /* if |x| < 0.0078125 = 2**-7 */
81 if (ix < 0x3f100000) { /* if |x| < 2**-14 */
82 if ((int) x == 0) { /* raise inexact if x != 0 */
83 ft = n == 0 ? (float) x : (float) (-one / x);
84 }
85 return (ft);
86 }
87 z = (x * T0) * (T1 + x * x);
88 ft = n == 0 ? (float) z : (float) (-one / z);
89 return (ft);
90 }
91 z = x * x;
92 w = ((P0 * x) * (P1 + z * (P2 + z)) * (P3 + z * (P4 + z)))
93 * (P5 + z * (P6 + z * (P7 + z)));
94 ft = n == 0 ? (float) w : (float) (-one / w);
95 return (ft);
96 }
97