POK
tanf.c
1 /*
2  * POK header
3  *
4  * The following file is a part of the POK project. Any modification should
5  * made according to the POK licence. You CANNOT use this file or a part of
6  * this file is this part of a file for your own project
7  *
8  * For more information on the POK licence, please see our LICENCE FILE
9  *
10  * Please follow the coding guidelines described in doc/CODING_GUIDELINES
11  *
12  * Copyright (c) 2007-2009 POK team
13  *
14  * Created by julien on Fri Jan 30 14:41:34 2009
15  */
16 
17 /* s_tanf.c -- float version of s_tan.c.
18  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
19  */
20 
21 /*
22  * ====================================================
23  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
24  *
25  * Developed at SunPro, a Sun Microsystems, Inc. business.
26  * Permission to use, copy, modify, and distribute this
27  * software is freely granted, provided that this notice
28  * is preserved.
29  * ====================================================
30  */
31 
32 #ifdef POK_NEEDS_LIBMATH
33 
34 #include <libm.h>
35 #include "math_private.h"
36 
37 float
38 tanf(float x)
39 {
40  float y[2],z=0.0;
41  int32_t n, ix;
42 
43  GET_FLOAT_WORD(ix,x);
44 
45  /* |x| ~< pi/4 */
46  ix &= 0x7fffffff;
47  if(ix <= 0x3f490fda) return __kernel_tanf(x,z,1);
48 
49  /* tan(Inf or NaN) is NaN */
50  else if (ix>=0x7f800000) return x-x; /* NaN */
51 
52  /* argument reduction needed */
53  else {
54  n = __ieee754_rem_pio2f(x,y);
55  return __kernel_tanf(y[0],y[1],1-((n&1)<<1)); /* 1 -- n even
56  -1 -- n odd */
57  }
58 }
59 
60 #endif