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bc9f6000 1/* Truncate argument to nearest integral value not larger than the argument.
04277e02 2 Copyright (C) 1997-2019 Free Software Foundation, Inc.
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3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
5
6 The GNU C Library is free software; you can redistribute it and/or
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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.
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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
41bdb6e2 14 Lesser General Public License for more details.
bc9f6000 15
41bdb6e2 16 You should have received a copy of the GNU Lesser General Public
59ba27a6 17 License along with the GNU C Library; if not, see
5a82c748 18 <https://www.gnu.org/licenses/>. */
bc9f6000 19
7abf97be 20#define NO_MATH_REDIRECT
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21#include <math.h>
22
1ed0291c 23#include <math_private.h>
a1132b5e 24#include <libm-alias-double.h>
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25
26
27double
28__trunc (double x)
29{
30 int32_t i0, j0;
24ab7723 31 uint32_t i1;
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32 int sx;
33
34 EXTRACT_WORDS (i0, i1, x);
35 sx = i0 & 0x80000000;
36 j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
37 if (j0 < 20)
38 {
39 if (j0 < 0)
40 /* The magnitude of the number is < 1 so the result is +-0. */
41 INSERT_WORDS (x, sx, 0);
42 else
48252123 43 INSERT_WORDS (x, sx | (i0 & ~(0x000fffff >> j0)), 0);
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44 }
45 else if (j0 > 51)
46 {
47 if (j0 == 0x400)
48 /* x is inf or NaN. */
49 return x + x;
50 }
51 else
52 {
53 INSERT_WORDS (x, i0, i1 & ~(0xffffffffu >> (j0 - 20)));
54 }
55
56 return x;
57}
bdf20bea 58#ifndef __trunc
a1132b5e 59libm_alias_double (__trunc, trunc)
bc9f6000 60#endif