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n_sincos.c revision 1.6 
      1 /*	$NetBSD: n_sincos.c,v 1.6 2003/08/07 16:44:52 agc 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. Neither the name of the University nor the names of its contributors
     15  *    may be used to endorse or promote products derived from this software
     16  *    without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     28  * SUCH DAMAGE.
     29  */
     30 
     31 #ifndef lint
     32 #if 0
     33 static char sccsid[] = "@(#)sincos.c	8.1 (Berkeley) 6/4/93";
     34 #endif
     35 #endif /* not lint */
     36 
     37 #define _LIBM_DECLARE
     38 #include "mathimpl.h"
     39 #include "trig.h"
     40 
     41 double
     42 sin(double x)
     43 {
     44 	double a,c,z;
     45 
     46         if(!finite(x))		/* sin(NaN) and sin(INF) must be NaN */
     47 		return x-x;
     48 	x=drem(x,PI2);		/* reduce x into [-PI,PI] */
     49 	a=copysign(x,__one);
     50 	if (a >= PIo4) {
     51 		if(a >= PI3o4)		/* ... in [3PI/4,PI] */
     52 			x = copysign((a = PI-a),x);
     53 		else {			/* ... in [PI/4,3PI/4]  */
     54 			a = PIo2-a;		/* rtn. sign(x)*C(PI/2-|x|) */
     55 			z = a*a;
     56 			c = cos__C(z);
     57 			z *= __half;
     58 			a = (z >= thresh ? __half-((z-__half)-c) : __one-(z-c));
     59 			return copysign(a,x);
     60 		}
     61 	}
     62 
     63 	if (a < __small) {		/* rtn. S(x) */
     64 		z = __big+a;
     65 		return x;
     66 	}
     67 	return x+x*sin__S(x*x);
     68 }
     69 
     70 float
     71 sinf(float x)
     72 {
     73 	return sin(x);
     74 }
     75 
     76 double
     77 cos(double x)
     78 {
     79 	double a,c,z,s = 1.0;
     80 
     81 	if(!finite(x))		/* cos(NaN) and cos(INF) must be NaN */
     82 		return x-x;
     83 	x=drem(x,PI2);		/* reduce x into [-PI,PI] */
     84 	a=copysign(x,__one);
     85 	if (a >= PIo4) {
     86 		if (a >= PI3o4) {	/* ... in [3PI/4,PI] */
     87 			a = PI-a;
     88 			s = __negone;
     89 		}
     90 		else {			/* ... in [PI/4,3PI/4] */
     91 			a = PIo2-a;
     92 			return a+a*sin__S(a*a);	/* rtn. S(PI/2-|x|) */
     93 		}
     94 	}
     95 	if (a < __small) {
     96 		z = __big+a;
     97 		return s;		/* rtn. s*C(a) */
     98 	}
     99 	z = a*a;
    100 	c = cos__C(z);
    101 	z *= __half;
    102 	a = (z >= thresh ? __half-((z-__half)-c) : __one-(z-c));
    103 	return copysign(a,s);
    104 }
    105 
    106 float
    107 cosf(float x)
    108 {
    109 	return cos(x);
    110 }
    111