138 lines
3.4 KiB
C
138 lines
3.4 KiB
C
/* sincos.c - math routines */
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/* Copyright 1992-1993 Wind River Systems, Inc. */
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/*
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modification history
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--------------------
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01f,05feb93,jdi doc changes based on kdl review.
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01e,02dec92,jdi doc tweaks.
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01d,28oct92,jdi documentation cleanup.
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01c,21sep92,smb changed function headers for mg.
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01b,20sep92,smb documentation additions
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01a,08jul92,smb documentation.
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*/
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/*
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DESCRIPTION
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* Copyright (c) 1987 Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by the University of California, Berkeley. The name of the
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* University may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*
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* All recipients should regard themselves as participants in an ongoing
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* research project and hence should feel obligated to report their
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* experiences (good or bad) with these elementary function codes, using
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* the sendbug(8) program, to the authors.
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*
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SEE ALSO: American National Standard X3.159-1989
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NOMANUAL
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*/
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#include "vxWorks.h"
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#include "math.h"
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#include "private/trigP.h"
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/*******************************************************************************
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*
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* sin - compute a sine (ANSI)
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*
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* This routine computes the sine of <x> in double precision.
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* The angle <x> is expressed in radians.
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*
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* INCLUDE FILES: math.h
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*
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* RETURNS: The double-precision sine of <x>.
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*
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* SEE ALSO: mathALib
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*/
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double sin
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(
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double x /* angle in radians */
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)
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{
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double a,c,z;
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if(!finite(x)) /* sin(NaN) and sin(INF) must be NaN */
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return x-x;
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x=drem(x,PI2); /* reduce x into [-PI,PI] */
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a=copysign(x,one);
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if (a >= PIo4) {
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if(a >= PI3o4) /* ... in [3PI/4,PI] */
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x = copysign((a = PI-a),x);
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else { /* ... in [PI/4,3PI/4] */
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a = PIo2-a; /* rtn. sign(x)*C(PI/2-|x|) */
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z = a*a;
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c = cos__C(z);
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z *= half;
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a = (z >= thresh ? half-((z-half)-c) : one-(z-c));
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return copysign(a,x);
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}
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}
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if (a < small) { /* rtn. S(x) */
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big+a;
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return x;
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}
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return x+x*sin__S(x*x);
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}
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/*******************************************************************************
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*
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* cos - compute a cosine (ANSI)
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*
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* This routine computes the cosine of <x> in double precision.
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* The angle <x> is expressed in radians.
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*
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* INCLUDE FILES: math.h
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*
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* RETURNS: The double-precision cosine of <x>.
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*
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* SEE ALSO: mathALib
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*/
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double cos
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(
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double x /* angle in radians */
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)
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{
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double a,c,z,s = 1.0;
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if(!finite(x)) /* cos(NaN) and cos(INF) must be NaN */
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return x-x;
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x=drem(x,PI2); /* reduce x into [-PI,PI] */
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a=copysign(x,one);
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if (a >= PIo4) {
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if (a >= PI3o4) { /* ... in [3PI/4,PI] */
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a = PI-a;
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s = negone;
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}
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else { /* ... in [PI/4,3PI/4] */
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a = PIo2-a;
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return a+a*sin__S(a*a); /* rtn. S(PI/2-|x|) */
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}
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}
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if (a < small) {
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big+a;
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return s; /* rtn. s*C(a) */
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}
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z = a*a;
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c = cos__C(z);
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z *= half;
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a = (z >= thresh ? half-((z-half)-c) : one-(z-c));
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return copysign(a,s);
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}
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