1/* Round float value to long long int.
2 Copyright (C) 1997-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <fenv.h>
20#include <limits.h>
21#include <math.h>
22
23#include <math_private.h>
24#include <libm-alias-float.h>
25#include <fix-fp-int-convert-overflow.h>
26
27
28long long int
29__llroundf (float x)
30{
31 int32_t j0;
32 uint32_t i;
33 long long int result;
34 int sign;
35
36 GET_FLOAT_WORD (i, x);
37 j0 = ((i >> 23) & 0xff) - 0x7f;
38 sign = (i & 0x80000000) != 0 ? -1 : 1;
39 i &= 0x7fffff;
40 i |= 0x800000;
41
42 if (j0 < (int32_t) (8 * sizeof (long long int)) - 1)
43 {
44 if (j0 < 0)
45 return j0 < -1 ? 0 : sign;
46 else if (j0 >= 23)
47 result = (long long int) i << (j0 - 23);
48 else
49 {
50 i += 0x400000 >> j0;
51
52 result = i >> (23 - j0);
53 }
54 }
55 else
56 {
57#ifdef FE_INVALID
58 /* The number is too large. Unless it rounds to LLONG_MIN,
59 FE_INVALID must be raised and the return value is
60 unspecified. */
61 if (FIX_FLT_LLONG_CONVERT_OVERFLOW && x != (float) LLONG_MIN)
62 {
63 feraiseexcept (FE_INVALID);
64 return sign == 1 ? LLONG_MAX : LLONG_MIN;
65 }
66#endif
67 return (long long int) x;
68 }
69
70 return sign * result;
71}
72
73libm_alias_float (__llround, llround)
74

source code of glibc/sysdeps/ieee754/flt-32/s_llroundf.c