xref: /openbsd/lib/libm/src/s_sinf.c (revision 5dea098c)
1 /* s_sinf.c -- float version of s_sin.c.
2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3  */
4 
5 /*
6  * ====================================================
7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8  *
9  * Developed at SunPro, a Sun Microsystems, Inc. business.
10  * Permission to use, copy, modify, and distribute this
11  * software is freely granted, provided that this notice
12  * is preserved.
13  * ====================================================
14  */
15 
16 #include "math.h"
17 #include "math_private.h"
18 
19 float
20 sinf(float x)
21 {
22 	float y[2],z=0.0;
23 	int32_t n, ix;
24 
25 	GET_FLOAT_WORD(ix,x);
26 
27     /* |x| ~< pi/4 */
28 	ix &= 0x7fffffff;
29 	if(ix <= 0x3f490fd8) {
30 	    if(ix<0x39800000)			/* if x < 2**-12 */
31 		if(((int)x)==0) return x;	/* generate inexact */
32 	    return __kernel_sinf(x,z,0);
33 	}
34 
35     /* sin(Inf or NaN) is NaN */
36 	else if (ix>=0x7f800000) return x-x;
37 
38     /* argument reduction needed */
39 	else {
40 	    n = __ieee754_rem_pio2f(x,y);
41 	    switch(n&3) {
42 		case 0: return  __kernel_sinf(y[0],y[1],1);
43 		case 1: return  __kernel_cosf(y[0],y[1]);
44 		case 2: return -__kernel_sinf(y[0],y[1],1);
45 		default:
46 			return -__kernel_cosf(y[0],y[1]);
47 	    }
48 	}
49 }
50 DEF_STD(sinf);
51