/*--------------------------------------------------------------------

 *© Portions copyright (c) 2006 Nokia Corporation.  All rights reserved.

 *--------------------------------------------------------------------

*/

/* @(#)s_sin.c 5.1 93/09/24 */

/*

 * ====================================================

 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.

 *

 * Developed at SunPro, a Sun Microsystems, Inc. business.

 * Permission to use, copy, modify, and distribute this

 * software is freely granted, provided that this notice

 * is preserved.

 * ====================================================

 */

#ifndef __SYMBIAN32__

#ifndef lint

static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_sin.c,v 1.9 2003/07/23 04:53:47 peter Exp $";

#endif

#endif //__SYMBIAN32__

/* sin(x)

 * Return sine function of x.

 *

 * kernel function:

 *	__kernel_sin		... sine function on [-pi/4,pi/4]

 *	__kernel_cos		... cose function on [-pi/4,pi/4]

 *	__ieee754_rem_pio2	... argument reduction routine

 *

 * Method.

 *      Let S,C and T denote the sin, cos and tan respectively on

 *	[-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2

 *	in [-pi/4 , +pi/4], and let n = k mod 4.

 *	We have

 *

 *          n        sin(x)      cos(x)        tan(x)

 *     ----------------------------------------------------------

 *	    0	       S	   C		 T

 *	    1	       C	  -S		-1/T

 *	    2	      -S	  -C		 T

 *	    3	      -C	   S		-1/T

 *     ----------------------------------------------------------

 *

 * Special cases:

 *      Let trig be any of sin, cos, or tan.

 *      trig(+-INF)  is NaN, with signals;

 *      trig(NaN)    is that NaN;

 *

 * Accuracy:

 *	TRIG(x) returns trig(x) nearly rounded

 */

#include <math.h>

#include "math_private.h"

EXPORT_C double sin(double x)

{

	double y[2],z=0.0;

	int32_t n, ix;

    /* High word of x. */

	GET_HIGH_WORD(ix,x);

    /* |x| ~< pi/4 */

	ix &= 0x7fffffff;

	if(ix <= 0x3fe921fb) return __kernel_sin(x,z,0);

    /* sin(Inf or NaN) is NaN */

	else if (ix>=0x7ff00000)

	#ifdef __SYMBIAN32__

	return (0.0/0.0);

	#else

	return x-x;

	#endif //__SYMBIAN32__

    /* argument reduction needed */

	else {

	    n = __ieee754_rem_pio2(x,y);

	    switch(n&3) {

		case 0: return  __kernel_sin(y[0],y[1],1);

		case 1: return  __kernel_cos(y[0],y[1]);

		case 2: return -__kernel_sin(y[0],y[1],1);

		default:

			return -__kernel_cos(y[0],y[1]);

	    }

	}

}