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