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/* $NetBSD: n_sincos.c,v 1.1 1995/10/10 23:37:04 ragge Exp $ */
/*
* Copyright (c) 1987, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static char sccsid[] = "@(#)sincos.c 8.1 (Berkeley) 6/4/93";
#endif /* not lint */
#include "mathimpl.h"
#include "trig.h"
double
sin(x)
double x;
{
double a,c,z;
if(!finite(x)) /* sin(NaN) and sin(INF) must be NaN */
return x-x;
x=drem(x,PI2); /* reduce x into [-PI,PI] */
a=copysign(x,one);
if (a >= PIo4) {
if(a >= PI3o4) /* ... in [3PI/4,PI] */
x = copysign((a = PI-a),x);
else { /* ... in [PI/4,3PI/4] */
a = PIo2-a; /* rtn. sign(x)*C(PI/2-|x|) */
z = a*a;
c = cos__C(z);
z *= half;
a = (z >= thresh ? half-((z-half)-c) : one-(z-c));
return copysign(a,x);
}
}
if (a < small) { /* rtn. S(x) */
big+a;
return x;
}
return x+x*sin__S(x*x);
}
double
cos(x)
double x;
{
double a,c,z,s = 1.0;
if(!finite(x)) /* cos(NaN) and cos(INF) must be NaN */
return x-x;
x=drem(x,PI2); /* reduce x into [-PI,PI] */
a=copysign(x,one);
if (a >= PIo4) {
if (a >= PI3o4) { /* ... in [3PI/4,PI] */
a = PI-a;
s = negone;
}
else { /* ... in [PI/4,3PI/4] */
a = PIo2-a;
return a+a*sin__S(a*a); /* rtn. S(PI/2-|x|) */
}
}
if (a < small) {
big+a;
return s; /* rtn. s*C(a) */
}
z = a*a;
c = cos__C(z);
z *= half;
a = (z >= thresh ? half-((z-half)-c) : one-(z-c));
return copysign(a,s);
}
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