1 /* Round argument to nearest integral value according to current rounding
2 direction.
3 Copyright (C) 1997-2022 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 #include <fenv.h>
21 #include <limits.h>
22 #include <math.h>
23
24 #include <math-narrow-eval.h>
25 #include <math_private.h>
26 #include <libm-alias-float.h>
27 #include <fix-fp-int-convert-overflow.h>
28
29 static const float two23[2] =
30 {
31 8.3886080000e+06, /* 0x4B000000 */
32 -8.3886080000e+06, /* 0xCB000000 */
33 };
34
35
36 long int
__lrintf(float x)37 __lrintf (float x)
38 {
39 int32_t j0;
40 uint32_t i0;
41 float w;
42 float t;
43 long int result;
44 int sx;
45
46 GET_FLOAT_WORD (i0, x);
47
48 sx = i0 >> 31;
49 j0 = ((i0 >> 23) & 0xff) - 0x7f;
50 i0 &= 0x7fffff;
51 i0 |= 0x800000;
52
53 if (j0 < (int32_t) (sizeof (long int) * 8) - 1)
54 {
55 if (j0 >= 23)
56 result = (long int) i0 << (j0 - 23);
57 else
58 {
59 w = math_narrow_eval (two23[sx] + x);
60 t = w - two23[sx];
61 GET_FLOAT_WORD (i0, t);
62 j0 = ((i0 >> 23) & 0xff) - 0x7f;
63 i0 &= 0x7fffff;
64 i0 |= 0x800000;
65
66 result = (j0 < 0 ? 0 : i0 >> (23 - j0));
67 }
68 }
69 else
70 {
71 #ifdef FE_INVALID
72 /* The number is too large. Unless it rounds to LONG_MIN,
73 FE_INVALID must be raised and the return value is
74 unspecified. */
75 if (FIX_FLT_LONG_CONVERT_OVERFLOW && x != (float) LONG_MIN)
76 {
77 feraiseexcept (FE_INVALID);
78 return sx == 0 ? LONG_MAX : LONG_MIN;
79 }
80 #endif
81 return (long int) x;
82 }
83
84 return sx ? -result : result;
85 }
86
87 libm_alias_float (__lrint, lrint)
88