n_sincos.c revision 1.1 1 /* $NetBSD: n_sincos.c,v 1.1 1995/10/10 23:37:04 ragge Exp $ */
2 /*
3 * Copyright (c) 1987, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 * must display the following acknowledgement:
16 * This product includes software developed by the University of
17 * California, Berkeley and its contributors.
18 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #ifndef lint
36 static char sccsid[] = "@(#)sincos.c 8.1 (Berkeley) 6/4/93";
37 #endif /* not lint */
38
39 #include "mathimpl.h"
40 #include "trig.h"
41 double
42 sin(x)
43 double x;
44 {
45 double a,c,z;
46
47 if(!finite(x)) /* sin(NaN) and sin(INF) must be NaN */
48 return x-x;
49 x=drem(x,PI2); /* reduce x into [-PI,PI] */
50 a=copysign(x,one);
51 if (a >= PIo4) {
52 if(a >= PI3o4) /* ... in [3PI/4,PI] */
53 x = copysign((a = PI-a),x);
54 else { /* ... in [PI/4,3PI/4] */
55 a = PIo2-a; /* rtn. sign(x)*C(PI/2-|x|) */
56 z = a*a;
57 c = cos__C(z);
58 z *= half;
59 a = (z >= thresh ? half-((z-half)-c) : one-(z-c));
60 return copysign(a,x);
61 }
62 }
63
64 if (a < small) { /* rtn. S(x) */
65 big+a;
66 return x;
67 }
68 return x+x*sin__S(x*x);
69 }
70
71 double
72 cos(x)
73 double x;
74 {
75 double a,c,z,s = 1.0;
76
77 if(!finite(x)) /* cos(NaN) and cos(INF) must be NaN */
78 return x-x;
79 x=drem(x,PI2); /* reduce x into [-PI,PI] */
80 a=copysign(x,one);
81 if (a >= PIo4) {
82 if (a >= PI3o4) { /* ... in [3PI/4,PI] */
83 a = PI-a;
84 s = negone;
85 }
86 else { /* ... in [PI/4,3PI/4] */
87 a = PIo2-a;
88 return a+a*sin__S(a*a); /* rtn. S(PI/2-|x|) */
89 }
90 }
91 if (a < small) {
92 big+a;
93 return s; /* rtn. s*C(a) */
94 }
95 z = a*a;
96 c = cos__C(z);
97 z *= half;
98 a = (z >= thresh ? half-((z-half)-c) : one-(z-c));
99 return copysign(a,s);
100 }
101