1 | /* Round to int long double floating-point values. |
2 | IBM extended format long double version. |
3 | Copyright (C) 2006-2022 Free Software Foundation, Inc. |
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 |
17 | License along with the GNU C Library; if not, see |
18 | <https://www.gnu.org/licenses/>. */ |
19 | |
20 | /* This has been coded in assembler because GCC makes such a mess of it |
21 | when it's coded in C. */ |
22 | |
23 | #define NO_MATH_REDIRECT |
24 | #include <math.h> |
25 | #include <math_private.h> |
26 | #include <math_ldbl_opt.h> |
27 | #include <float.h> |
28 | #include <ieee754.h> |
29 | |
30 | double round (double) asm ("__round" ); |
31 | |
32 | |
33 | long double |
34 | __roundl (long double x) |
35 | { |
36 | double xh, xl, hi, lo; |
37 | |
38 | ldbl_unpack (x, &xh, &xl); |
39 | |
40 | /* Return Inf, Nan, +/-0 unchanged. */ |
41 | if (__builtin_expect (xh != 0.0 |
42 | && __builtin_isless (__builtin_fabs (xh), |
43 | __builtin_inf ()), 1)) |
44 | { |
45 | hi = round (xh); |
46 | if (hi != xh) |
47 | { |
48 | /* The high part is not an integer; the low part only |
49 | affects the result if the high part is exactly half way |
50 | between two integers and the low part is nonzero with the |
51 | opposite sign. */ |
52 | if (fabs (x: hi - xh) == 0.5) |
53 | { |
54 | if (xh > 0 && xl < 0) |
55 | xh = hi - 1; |
56 | else if (xh < 0 && xl > 0) |
57 | xh = hi + 1; |
58 | else |
59 | xh = hi; |
60 | } |
61 | else |
62 | xh = hi; |
63 | xl = 0; |
64 | } |
65 | else |
66 | { |
67 | /* The high part is a nonzero integer. */ |
68 | lo = round (xl); |
69 | if (fabs (x: lo - xl) == 0.5) |
70 | { |
71 | if (xh > 0 && xl < 0) |
72 | xl = lo + 1; |
73 | else if (xh < 0 && lo > 0) |
74 | xl = lo - 1; |
75 | else |
76 | xl = lo; |
77 | } |
78 | else |
79 | xl = lo; |
80 | xh = hi; |
81 | ldbl_canonicalize_int (&xh, &xl); |
82 | } |
83 | } |
84 | else |
85 | /* Quiet signaling NaN arguments. */ |
86 | xh += xh; |
87 | |
88 | return ldbl_pack (xh, xl); |
89 | } |
90 | |
91 | long_double_symbol (libm, __roundl, roundl); |
92 | |