s_cosf.c revision 8870 
1/* s_cosf.c -- float version of s_cos.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#ifndef lint
17static char rcsid[] = "$Id: s_cosf.c,v 1.1.1.1 1994/08/19 09:39:58 jkh Exp $";
18#endif
19
20#include "math.h"
21#include "math_private.h"
22
23#ifdef __STDC__
24static const float one=1.0;
25#else
26static float one=1.0;
27#endif
28
29#ifdef __STDC__
30	float cosf(float x)
31#else
32	float cosf(x)
33	float x;
34#endif
35{
36	float y[2],z=0.0;
37	int32_t n,ix;
38
39	GET_FLOAT_WORD(ix,x);
40
41    /* |x| ~< pi/4 */
42	ix &= 0x7fffffff;
43	if(ix <= 0x3f490fd8) return __kernel_cosf(x,z);
44
45    /* cos(Inf or NaN) is NaN */
46	else if (ix>=0x7f800000) return x-x;
47
48    /* argument reduction needed */
49	else {
50	    n = __ieee754_rem_pio2f(x,y);
51	    switch(n&3) {
52		case 0: return  __kernel_cosf(y[0],y[1]);
53		case 1: return -__kernel_sinf(y[0],y[1],1);
54		case 2: return -__kernel_cosf(y[0],y[1]);
55		default:
56		        return  __kernel_sinf(y[0],y[1],1);
57	    }
58	}
59}
60