s_sinf.c revision 152871 
1/* s_sinf.c -- float version of s_sin.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 * Optimized by Bruce D. Evans.
4 */
5
6/*
7 * ====================================================
8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9 *
10 * Developed at SunPro, a Sun Microsystems, Inc. business.
11 * Permission to use, copy, modify, and distribute this
12 * software is freely granted, provided that this notice
13 * is preserved.
14 * ====================================================
15 */
16
17#ifndef lint
18static char rcsid[] = "$FreeBSD: head/lib/msun/src/s_sinf.c 152871 2005-11-28 05:46:13Z bde $";
19#endif
20
21#include "math.h"
22#define	INLINE_KERNEL_COSDF
23#define	INLINE_KERNEL_SINDF
24#include "math_private.h"
25#include "k_cosf.c"
26#include "k_sinf.c"
27
28/* Small multiples of pi/2 rounded to double precision. */
29static const double
30s1pio2 = 1*M_PI_2,			/* 0x3FF921FB, 0x54442D18 */
31s2pio2 = 2*M_PI_2,			/* 0x400921FB, 0x54442D18 */
32s3pio2 = 3*M_PI_2,			/* 0x4012D97C, 0x7F3321D2 */
33s4pio2 = 4*M_PI_2;			/* 0x401921FB, 0x54442D18 */
34
35float
36sinf(float x)
37{
38	float y[2];
39	int32_t n, hx, ix;
40
41	GET_FLOAT_WORD(hx,x);
42	ix = hx & 0x7fffffff;
43
44	if(ix <= 0x3f490fda) {		/* |x| ~<= pi/4 */
45	    if(ix<0x39800000)		/* |x| < 2**-12 */
46		if(((int)x)==0) return x;	/* x with inexact if x != 0 */
47	    return __kernel_sindf(x);
48	}
49	if(ix<=0x407b53d1) {		/* |x| ~<= 5*pi/4 */
50	    if(ix<=0x4016cbe3) {	/* |x| ~<= 3pi/4 */
51		if(hx>0)
52		    return __kernel_cosdf(x - s1pio2);
53		else
54		    return -__kernel_cosdf(x + s1pio2);
55	    } else
56		return -__kernel_sindf(x + (hx > 0 ? -s2pio2 : s2pio2));
57	}
58	if(ix<=0x40e231d5) {		/* |x| ~<= 9*pi/4 */
59	    if(ix<=0x40afeddf) {	/* |x| ~<= 7*pi/4 */
60		if(hx>0)
61		    return -__kernel_cosdf(x - s3pio2);
62		else
63		    return __kernel_cosdf(x + s3pio2);
64	    } else
65		return __kernel_sindf(x + (hx > 0 ? -s4pio2 : s4pio2));
66	}
67
68    /* sin(Inf or NaN) is NaN */
69	else if (ix>=0x7f800000) return x-x;
70
71    /* general argument reduction needed */
72	else {
73	    n = __ieee754_rem_pio2f(x,y);
74	    switch(n&3) {
75		case 0: return  __kernel_sindf((double)y[0]+y[1]);
76		case 1: return  __kernel_cosdf((double)y[0]+y[1]);
77		case 2: return -__kernel_sindf((double)y[0]+y[1]);
78		default:
79			return -__kernel_cosdf((double)y[0]+y[1]);
80	    }
81	}
82}
83