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n_sincos.c revision 1.5 
      1 /*	$NetBSD: n_sincos.c,v 1.5 2002/06/23 21:54:37 matt 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 #define _LIBM_DECLARE
     42 #include "mathimpl.h"
     43 #include "trig.h"
     44 
     45 double
     46 sin(double x)
     47 {
     48 	double a,c,z;
     49 
     50         if(!finite(x))		/* sin(NaN) and sin(INF) must be NaN */
     51 		return x-x;
     52 	x=drem(x,PI2);		/* reduce x into [-PI,PI] */
     53 	a=copysign(x,__one);
     54 	if (a >= PIo4) {
     55 		if(a >= PI3o4)		/* ... in [3PI/4,PI] */
     56 			x = copysign((a = PI-a),x);
     57 		else {			/* ... in [PI/4,3PI/4]  */
     58 			a = PIo2-a;		/* rtn. sign(x)*C(PI/2-|x|) */
     59 			z = a*a;
     60 			c = cos__C(z);
     61 			z *= __half;
     62 			a = (z >= thresh ? __half-((z-__half)-c) : __one-(z-c));
     63 			return copysign(a,x);
     64 		}
     65 	}
     66 
     67 	if (a < __small) {		/* rtn. S(x) */
     68 		z = __big+a;
     69 		return x;
     70 	}
     71 	return x+x*sin__S(x*x);
     72 }
     73 
     74 float
     75 sinf(float x)
     76 {
     77 	return sin(x);
     78 }
     79 
     80 double
     81 cos(double x)
     82 {
     83 	double a,c,z,s = 1.0;
     84 
     85 	if(!finite(x))		/* cos(NaN) and cos(INF) must be NaN */
     86 		return x-x;
     87 	x=drem(x,PI2);		/* reduce x into [-PI,PI] */
     88 	a=copysign(x,__one);
     89 	if (a >= PIo4) {
     90 		if (a >= PI3o4) {	/* ... in [3PI/4,PI] */
     91 			a = PI-a;
     92 			s = __negone;
     93 		}
     94 		else {			/* ... in [PI/4,3PI/4] */
     95 			a = PIo2-a;
     96 			return a+a*sin__S(a*a);	/* rtn. S(PI/2-|x|) */
     97 		}
     98 	}
     99 	if (a < __small) {
    100 		z = __big+a;
    101 		return s;		/* rtn. s*C(a) */
    102 	}
    103 	z = a*a;
    104 	c = cos__C(z);
    105 	z *= __half;
    106 	a = (z >= thresh ? __half-((z-__half)-c) : __one-(z-c));
    107 	return copysign(a,s);
    108 }
    109 
    110 float
    111 cosf(float x)
    112 {
    113 	return cos(x);
    114 }
    115