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 * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
23 */
24/*
25 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
26 * Use is subject to license terms.
27 */
28
29#pragma weak __tanf = tanf
30
31#include "libm.h"
32
33extern const int _TBL_ipio2_inf[];
34extern int __rem_pio2m(double *, double *, int, int, int, const int *);
35#if defined(__i386) && !defined(__amd64)
36extern int __swapRP(int);
37#endif
38
39static const double C[] = {
40	1.0,
41	4.46066928428959230679140546271810308098793029785e-0003,
42	4.92165316309189027066395283327437937259674072266e+0000,
43	-7.11410648161473480044492134766187518835067749023e-0001,
44	4.08549808374053391446523164631798863410949707031e+0000,
45	2.50411070398050927821032018982805311679840087891e+0000,
46	1.11492064560251158411574579076841473579406738281e+0001,
47	-1.50565540968422650891511693771462887525558471680e+0000,
48	-1.81484378878349295050043110677506774663925170898e+0000,
49	3.333335997532835641297409611782510896641e-0001,
50	2.999997598248363761541668282006867229939e+00,
51	0.636619772367581343075535,	/* 2^ -1  * 1.45F306DC9C883 */
52	0.5,
53	1.570796326734125614166,	/* 2^  0  * 1.921FB54400000 */
54	6.077100506506192601475e-11,	/* 2^-34  * 1.0B4611A626331 */
55};
56
57#define	one	C[0]
58#define	P0	C[1]
59#define	P1	C[2]
60#define	P2	C[3]
61#define	P3	C[4]
62#define	P4	C[5]
63#define	P5	C[6]
64#define	P6	C[7]
65#define	P7	C[8]
66#define	T0	C[9]
67#define	T1	C[10]
68#define	invpio2	C[11]
69#define	half	C[12]
70#define	pio2_1  C[13]
71#define	pio2_t	C[14]
72
73float
74tanf(float x)
75{
76	double	y, z, w;
77	float	f;
78	int	n, ix, hx, hy;
79	volatile int i __unused;
80
81	hx = *((int *)&x);
82	ix = hx & 0x7fffffff;
83
84	y = (double)x;
85
86	if (ix <= 0x4016cbe4) {		/* |x| < 3*pi/4 */
87		if (ix <= 0x3f490fdb) {		/* |x| < pi/4 */
88			if (ix < 0x3c000000) {		/* |x| < 2**-7 */
89				if (ix <= 0x39800000) {	/* |x| < 2**-12 */
90					i = (int)y;
91#ifdef lint
92					i = i;
93#endif
94					return (x);
95				}
96				return ((float)((y * T0) * (T1 + y * y)));
97			}
98			z = y * y;
99			return ((float)(((P0 * y) * (P1 + z * (P2 + z)) *
100			    (P3 + z * (P4 + z))) *
101			    (P5 + z * (P6 + z * (P7 + z)))));
102		}
103		if (hx > 0)
104			y = (y - pio2_1) - pio2_t;
105		else
106			y = (y + pio2_1) + pio2_t;
107		hy = ((int *)&y)[HIWORD] & ~0x80000000;
108		if (hy < 0x3f800000) {		/* |y| < 2**-7 */
109			z = (y * T0) * (T1 + y * y);
110			return ((float)(-one / z));
111		}
112		z = y * y;
113		w = ((P0 * y) * (P1 + z * (P2 + z)) * (P3 + z * (P4 + z))) *
114		    (P5 + z * (P6 + z * (P7 + z)));
115		return ((float)(-one / w));
116	}
117
118	if (ix <= 0x49c90fdb) {	/* |x| < 2^19*pi */
119#if defined(__i386) && !defined(__amd64)
120		int	rp;
121
122		rp = __swapRP(fp_extended);
123#endif
124		w = y * invpio2;
125		if (hx < 0)
126			n = (int)(w - half);
127		else
128			n = (int)(w + half);
129		y = (y - n * pio2_1) - n * pio2_t;
130#if defined(__i386) && !defined(__amd64)
131		if (rp != fp_extended)
132			(void) __swapRP(rp);
133#endif
134	} else {
135		if (ix >= 0x7f800000)
136			return (x / x);	/* sin(Inf or NaN) is NaN */
137		hy = ((int *)&y)[HIWORD];
138		n = ((hy >> 20) & 0x7ff) - 1046;
139		((int *)&w)[HIWORD] = (hy & 0xfffff) | 0x41600000;
140		((int *)&w)[LOWORD] = ((int *)&y)[LOWORD];
141		n = __rem_pio2m(&w, &y, n, 1, 0, _TBL_ipio2_inf);
142		if (hy < 0) {
143			y = -y;
144			n = -n;
145		}
146	}
147
148	hy = ((int *)&y)[HIWORD] & ~0x80000000;
149	if (hy < 0x3f800000) {		/* |y| < 2**-7 */
150		z = (y * T0) * (T1 + y * y);
151		f = ((n & 1) == 0)? (float)z : (float)(-one / z);
152		return (f);
153	}
154	z = y * y;
155	w = ((P0 * y) * (P1 + z * (P2 + z)) * (P3 + z * (P4 + z))) *
156	    (P5 + z * (P6 + z * (P7 + z)));
157	f = ((n & 1) == 0)? (float)w : (float)(-one / w);
158	return (f);
159}
160