include/elf.h: sync with GNU C library
[uclibc-ng.git] / libm / s_lround.c
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1 /* Round double value to long int.
2 Copyright (C) 1997, 2004 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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.
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.
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 <http://www.gnu.org/licenses/>. */
20 #include <math.h>
21 #include "math_private.h"
23 long int
24 lround (double x)
26 int32_t _j0;
27 u_int32_t i1, i0;
28 long int result;
29 int sign;
31 EXTRACT_WORDS (i0, i1, x);
32 _j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
33 sign = (i0 & 0x80000000) != 0 ? -1 : 1;
34 i0 &= 0xfffff;
35 i0 |= 0x100000;
37 if (_j0 < 20)
39 if (_j0 < 0)
40 return _j0 < -1 ? 0 : sign;
41 else
43 i0 += 0x80000 >> _j0;
45 result = i0 >> (20 - _j0);
48 else if (_j0 < (int32_t) (8 * sizeof (long int)) - 1)
50 if (_j0 >= 52)
51 result = ((long int) i0 << (_j0 - 20)) | (i1 << (_j0 - 52));
52 else
54 u_int32_t j = i1 + (0x80000000 >> (_j0 - 20));
55 if (j < i1)
56 ++i0;
58 if (_j0 == 20)
59 result = (long int) i0;
60 else
61 result = ((long int) i0 << (_j0 - 20)) | (j >> (52 - _j0));
64 else
66 /* The number is too large. It is left implementation defined
67 what happens. */
68 return (long int) x;
71 return sign * result;
73 libm_hidden_def(lround)