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 #include "math.h"
17 #include "math_private.h"
18
19 float
cosf(float x)20 cosf(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 1.0; /* generate inexact */
32 return __kernel_cosf(x,z);
33 }
34
35
36 /* cos(Inf or NaN) is NaN */
37 else if (ix>=0x7f800000) return x-x;
38
39 /* argument reduction needed */
40 else {
41 n = __ieee754_rem_pio2f(x,y);
42 switch(n&3) {
43 case 0: return __kernel_cosf(y[0],y[1]);
44 case 1: return -__kernel_sinf(y[0],y[1],1);
45 case 2: return -__kernel_cosf(y[0],y[1]);
46 default:
47 return __kernel_sinf(y[0],y[1],1);
48 }
49 }
50 }
51 DEF_STD(cosf);
52