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comparison packages/language/c/libm/current/src/float/portable-api/sf_tan.c @ 3337:77f9d3253c3e

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Add: Complex number header and library (single and double precision floating point), port from Newlib. Add: Single precision floating point library, port from Newlib. [ Bugzilla 1001539 ]
author vae
date Sun, 25 Aug 2013 14:38:57 +0000
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3336:8ecac279f33c 3337:77f9d3253c3e
1 //===========================================================================
2 //
3 // sf_tan.c
4 //
5 // Part of the standard mathematical function library
6 //
7 //===========================================================================
8 // ####ECOSGPLCOPYRIGHTBEGIN####
9 // -------------------------------------------
10 // This file is part of eCos, the Embedded Configurable Operating System.
11 // Copyright (C) 2012 Free Software Foundation, Inc.
12 //
13 // eCos is free software; you can redistribute it and/or modify it under
14 // the terms of the GNU General Public License as published by the Free
15 // Software Foundation; either version 2 or (at your option) any later
16 // version.
17 //
18 // eCos is distributed in the hope that it will be useful, but WITHOUT
19 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
20 // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
21 // for more details.
22 //
23 // You should have received a copy of the GNU General Public License
24 // along with eCos; if not, write to the Free Software Foundation, Inc.,
25 // 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
26 //
27 // As a special exception, if other files instantiate templates or use
28 // macros or inline functions from this file, or you compile this file
29 // and link it with other works to produce a work based on this file,
30 // this file does not by itself cause the resulting work to be covered by
31 // the GNU General Public License. However the source code for this file
32 // must still be made available in accordance with section (3) of the GNU
33 // General Public License v2.
34 //
35 // This exception does not invalidate any other reasons why a work based
36 // on this file might be covered by the GNU General Public License.
37 // -------------------------------------------
38 // ####ECOSGPLCOPYRIGHTEND####
39 //===========================================================================
40 //#####DESCRIPTIONBEGIN####
41 //
42 // Author(s):
43 // Contributors: visar, ilijak
44 // Date: 2012-03-08
45 // Purpose:
46 // Description:
47 // Usage:
48 //
49 //####DESCRIPTIONEND####
50 //
51 //===========================================================================
52
53 // CONFIGURATION
54
55 #include <pkgconf/libm.h> // Configuration header
56
57 // Include the Math library?
58 #ifdef CYGPKG_LIBM
59
60 // Derived from code with the following copyright
61
62
63 /* sf_tan.c -- float version of s_tan.c.
64 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
65 */
66
67 /*
68 * ====================================================
69 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
70 *
71 * Developed at SunPro, a Sun Microsystems, Inc. business.
72 * Permission to use, copy, modify, and distribute this
73 * software is freely granted, provided that this notice
74 * is preserved.
75 * ====================================================
76 */
77
78
79 #include "mathincl/fdlibm.h"
80
81 #ifdef __STDC__
82 float tanf(float x)
83 #else
84 float tanf(x)
85 float x;
86 #endif
87 {
88 float y[2],z=0.0;
89 __int32_t n,ix;
90
91 ix = CYG_LIBM_WORD(x);
92
93 /* |x| ~< pi/4 */
94 ix &= 0x7fffffff;
95 if(ix <= 0x3f490fda) return __kernel_tanf(x,z,1);
96
97 /* tan(Inf or NaN) is NaN */
98 else if (!FLT_UWORD_IS_FINITE(ix)) return x-x; /* NaN */
99
100 /* argument reduction needed */
101 else {
102 n = __ieee754_rem_pio2f(x,y);
103 return __kernel_tanf(y[0],y[1],1-((n&1)<<1)); /* 1 -- n even
104 -1 -- n odd */
105 }
106 }
107
108 #endif // ifdef CYGPKG_LIBM
109
110 // EOF sf_tan.c