1 /*-
2 * Copyright (c) 2007 Steven G. Kargl
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
10 * disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27
28 /*
29 * Limited testing on pseudorandom numbers drawn within [-2e8:4e8] shows
30 * an accuracy of <= 0.7412 ULP.
31 */
32
33
34 #include "e_rem_pio2l.h"
35
36 long double
cosl(long double x)37 cosl(long double x)
38 {
39 union IEEEl2bits z;
40 int e0;
41 long double y[2];
42 long double hi, lo;
43
44 z.e = x;
45 z.bits.sign = 0;
46
47 /* If x = NaN or Inf, then cos(x) = NaN. */
48 if (z.bits.exp == 32767)
49 return __math_invalidl(x);
50
51 /* If x = +-0, then cos(x) = 1 */
52 if (x == 0)
53 return (1.0L);
54
55 /* Optimize the case where x is already within range. */
56 if (z.e < _M_PI_4L)
57 return (__kernel_cosl(z.e, 0));
58
59 e0 = __ieee754_rem_pio2l(x, y);
60 hi = y[0];
61 lo = y[1];
62
63 switch (e0 & 3) {
64 case 0:
65 hi = __kernel_cosl(hi, lo);
66 break;
67 case 1:
68 hi = - __kernel_sinl(hi, lo, 1);
69 break;
70 case 2:
71 hi = - __kernel_cosl(hi, lo);
72 break;
73 case 3:
74 hi = __kernel_sinl(hi, lo, 1);
75 break;
76 }
77
78 return (hi);
79 }
80
81 #if defined(_HAVE_ALIAS_ATTRIBUTE)
82 #ifndef __clang__
83 #pragma GCC diagnostic ignored "-Wmissing-attributes"
84 #endif
85 __strong_reference(cosl, _cosl);
86 #endif
87
88
