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1 | /* Ceil (round to +inf) long double floating-point values. |
2 | IBM extended format long double version. | |
d4697bc9 | 3 | Copyright (C) 2006-2014 Free Software Foundation, Inc. |
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4 | This file is part of the GNU C Library. |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
7 | modify it under the terms of the GNU Lesser General Public | |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
10 | ||
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 PE |
17 | License along with the GNU C Library; if not, see |
18 | <http://www.gnu.org/licenses/>. */ | |
f964490f | 19 | |
f964490f | 20 | #include <math.h> |
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21 | #include <math_ldbl_opt.h> |
22 | #include <float.h> | |
23 | #include <ieee754.h> | |
24 | ||
25 | ||
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26 | long double |
27 | __ceill (long double x) | |
f964490f | 28 | { |
5c68d401 | 29 | double xh, xl, hi, lo; |
f964490f | 30 | |
5c68d401 | 31 | ldbl_unpack (x, &xh, &xl); |
f964490f | 32 | |
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33 | /* Return Inf, Nan, +/-0 unchanged. */ |
34 | if (__builtin_expect (xh != 0.0 | |
35 | && __builtin_isless (__builtin_fabs (xh), | |
36 | __builtin_inf ()), 1)) | |
16f0eced | 37 | { |
5c68d401 | 38 | double orig_xh; |
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39 | |
40 | /* Long double arithmetic, including the canonicalisation below, | |
41 | only works in round-to-nearest mode. */ | |
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42 | |
43 | /* Convert the high double to integer. */ | |
44 | orig_xh = xh; | |
45 | hi = ldbl_nearbyint (xh); | |
46 | ||
47 | /* Subtract integral high part from the value. */ | |
48 | xh -= hi; | |
49 | ldbl_canonicalize (&xh, &xl); | |
50 | ||
51 | /* Now convert the low double, adjusted for any remainder from the | |
52 | high double. */ | |
53 | lo = ldbl_nearbyint (xh); | |
54 | ||
55 | /* Adjust the result when the remainder is non-zero. nearbyint | |
56 | rounds values to the nearest integer, and values halfway | |
57 | between integers to the nearest even integer. ceill must | |
58 | round towards +Inf. */ | |
59 | xh -= lo; | |
60 | ldbl_canonicalize (&xh, &xl); | |
61 | ||
62 | if (xh > 0.0 || (xh == 0.0 && xl > 0.0)) | |
63 | lo += 1.0; | |
64 | ||
65 | /* Ensure the final value is canonical. In certain cases, | |
66 | rounding causes hi,lo calculated so far to be non-canonical. */ | |
67 | xh = hi; | |
68 | xl = lo; | |
69 | ldbl_canonicalize (&xh, &xl); | |
70 | ||
71 | /* Ensure we return -0 rather than +0 when appropriate. */ | |
72 | if (orig_xh < 0.0) | |
73 | xh = -__builtin_fabs (xh); | |
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74 | } |
75 | ||
5c68d401 | 76 | return ldbl_pack (xh, xl); |
f964490f RM |
77 | } |
78 | ||
79 | long_double_symbol (libm, __ceill, ceill); |