1 /* $NetBSD: n_sincos.c,v 1.3 1999/07/02 15:37:37 simonb 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 #if 0 37 static char sccsid[] = "@(#)sincos.c 8.1 (Berkeley) 6/4/93"; 38 #endif 39 #endif /* not lint */ 40 41 #include "mathimpl.h" 42 #include "trig.h" 43 double 44 sin(x) 45 double x; 46 { 47 double a,c,z; 48 49 if(!finite(x)) /* sin(NaN) and sin(INF) must be NaN */ 50 return x-x; 51 x=drem(x,PI2); /* reduce x into [-PI,PI] */ 52 a=copysign(x,one); 53 if (a >= PIo4) { 54 if(a >= PI3o4) /* ... in [3PI/4,PI] */ 55 x = copysign((a = PI-a),x); 56 else { /* ... in [PI/4,3PI/4] */ 57 a = PIo2-a; /* rtn. sign(x)*C(PI/2-|x|) */ 58 z = a*a; 59 c = cos__C(z); 60 z *= half; 61 a = (z >= thresh ? half-((z-half)-c) : one-(z-c)); 62 return copysign(a,x); 63 } 64 } 65 66 if (a < small) { /* rtn. S(x) */ 67 z = big+a; 68 return x; 69 } 70 return x+x*sin__S(x*x); 71 } 72 73 double 74 cos(x) 75 double x; 76 { 77 double a,c,z,s = 1.0; 78 79 if(!finite(x)) /* cos(NaN) and cos(INF) must be NaN */ 80 return x-x; 81 x=drem(x,PI2); /* reduce x into [-PI,PI] */ 82 a=copysign(x,one); 83 if (a >= PIo4) { 84 if (a >= PI3o4) { /* ... in [3PI/4,PI] */ 85 a = PI-a; 86 s = negone; 87 } 88 else { /* ... in [PI/4,3PI/4] */ 89 a = PIo2-a; 90 return a+a*sin__S(a*a); /* rtn. S(PI/2-|x|) */ 91 } 92 } 93 if (a < small) { 94 z = big+a; 95 return s; /* rtn. s*C(a) */ 96 } 97 z = a*a; 98 c = cos__C(z); 99 z *= half; 100 a = (z >= thresh ? half-((z-half)-c) : one-(z-c)); 101 return copysign(a,s); 102 } 103