1 | /* k_cosf.c -- float version of k_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 | #if defined(LIBM_SCCS) && !defined(lint) |
17 | static char rcsid[] = "$NetBSD: k_cosf.c,v 1.4 1995/05/10 20:46:23 jtc Exp $" ; |
18 | #endif |
19 | |
20 | #include <math.h> |
21 | #include <math_private.h> |
22 | |
23 | static const float |
24 | one = 1.0000000000e+00, /* 0x3f800000 */ |
25 | C1 = 4.1666667908e-02, /* 0x3d2aaaab */ |
26 | C2 = -1.3888889225e-03, /* 0xbab60b61 */ |
27 | C3 = 2.4801587642e-05, /* 0x37d00d01 */ |
28 | C4 = -2.7557314297e-07, /* 0xb493f27c */ |
29 | C5 = 2.0875723372e-09, /* 0x310f74f6 */ |
30 | C6 = -1.1359647598e-11; /* 0xad47d74e */ |
31 | |
32 | float __kernel_cosf(float x, float y) |
33 | { |
34 | float a,hz,z,r,qx; |
35 | int32_t ix; |
36 | GET_FLOAT_WORD(ix,x); |
37 | ix &= 0x7fffffff; /* ix = |x|'s high word*/ |
38 | if(ix<0x32000000) { /* if x < 2**27 */ |
39 | if(((int)x)==0) return one; /* generate inexact */ |
40 | } |
41 | z = x*x; |
42 | r = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*C6))))); |
43 | if(ix < 0x3e99999a) /* if |x| < 0.3 */ |
44 | return one - ((float)0.5*z - (z*r - x*y)); |
45 | else { |
46 | if(ix > 0x3f480000) { /* x > 0.78125 */ |
47 | qx = (float)0.28125; |
48 | } else { |
49 | SET_FLOAT_WORD(qx,ix-0x01000000); /* x/4 */ |
50 | } |
51 | hz = (float)0.5*z-qx; |
52 | a = one-qx; |
53 | return a - (hz - (z*r-x*y)); |
54 | } |
55 | } |
56 | |