1/* Round float to integer away from zero.
2 Copyright (C) 1997-2021 Free Software Foundation, Inc.
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
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#define NO_MATH_REDIRECT
21#include <math.h>
22
23#include <math_private.h>
24#include <libm-alias-float.h>
25#include <math-use-builtins.h>
26
27
28float
29__roundf (float x)
30{
31#if USE_ROUNDF_BUILTIN
32 return __builtin_roundf (x);
33#else
34 /* Use generic implementation. */
35 int32_t i0, j0;
36
37 GET_FLOAT_WORD (i0, x);
38 j0 = ((i0 >> 23) & 0xff) - 0x7f;
39 if (j0 < 23)
40 {
41 if (j0 < 0)
42 {
43 i0 &= 0x80000000;
44 if (j0 == -1)
45 i0 |= 0x3f800000;
46 }
47 else
48 {
49 uint32_t i = 0x007fffff >> j0;
50 if ((i0 & i) == 0)
51 /* X is integral. */
52 return x;
53
54 i0 += 0x00400000 >> j0;
55 i0 &= ~i;
56 }
57 }
58 else
59 {
60 if (j0 == 0x80)
61 /* Inf or NaN. */
62 return x + x;
63 else
64 return x;
65 }
66
67 SET_FLOAT_WORD (x, i0);
68 return x;
69#endif /* ! USE_ROUNDF_BUILTIN */
70}
71libm_alias_float (__round, round)
72