xref: /freebsd/lib/msun/src/s_sinf.c (revision a0b9e2e854027e6ff61fb075a1309dbc71c42b54)
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 #include <sys/cdefs.h>
18 __FBSDID("$FreeBSD$");
19 
20 #include <float.h>
21 
22 #include "math.h"
23 #define	INLINE_KERNEL_COSDF
24 #define	INLINE_KERNEL_SINDF
25 #define INLINE_REM_PIO2F
26 #include "math_private.h"
27 #include "e_rem_pio2f.c"
28 #include "k_cosf.c"
29 #include "k_sinf.c"
30 
31 /* Small multiples of pi/2 rounded to double precision. */
32 static const double
33 s1pio2 = 1*M_PI_2,			/* 0x3FF921FB, 0x54442D18 */
34 s2pio2 = 2*M_PI_2,			/* 0x400921FB, 0x54442D18 */
35 s3pio2 = 3*M_PI_2,			/* 0x4012D97C, 0x7F3321D2 */
36 s4pio2 = 4*M_PI_2;			/* 0x401921FB, 0x54442D18 */
37 
38 float
39 sinf(float x)
40 {
41 	double y;
42 	int32_t n, hx, ix;
43 
44 	GET_FLOAT_WORD(hx,x);
45 	ix = hx & 0x7fffffff;
46 
47 	if(ix <= 0x3f490fda) {		/* |x| ~<= pi/4 */
48 	    if(ix<0x39800000)		/* |x| < 2**-12 */
49 		if(((int)x)==0) return x;	/* x with inexact if x != 0 */
50 	    return __kernel_sindf(x);
51 	}
52 	if(ix<=0x407b53d1) {		/* |x| ~<= 5*pi/4 */
53 	    if(ix<=0x4016cbe3) {	/* |x| ~<= 3pi/4 */
54 		if(hx>0)
55 		    return __kernel_cosdf(x - s1pio2);
56 		else
57 		    return -__kernel_cosdf(x + s1pio2);
58 	    } else
59 		return __kernel_sindf((hx > 0 ? s2pio2 : -s2pio2) - x);
60 	}
61 	if(ix<=0x40e231d5) {		/* |x| ~<= 9*pi/4 */
62 	    if(ix<=0x40afeddf) {	/* |x| ~<= 7*pi/4 */
63 		if(hx>0)
64 		    return -__kernel_cosdf(x - s3pio2);
65 		else
66 		    return __kernel_cosdf(x + s3pio2);
67 	    } else
68 		return __kernel_sindf(x + (hx > 0 ? -s4pio2 : s4pio2));
69 	}
70 
71     /* sin(Inf or NaN) is NaN */
72 	else if (ix>=0x7f800000) return x-x;
73 
74     /* general argument reduction needed */
75 	else {
76 	    n = __ieee754_rem_pio2f(x,&y);
77 	    switch(n&3) {
78 		case 0: return  __kernel_sindf(y);
79 		case 1: return  __kernel_cosdf(y);
80 		case 2: return  __kernel_sindf(-y);
81 		default:
82 			return -__kernel_cosdf(y);
83 	    }
84 	}
85 }
86