1 /* Round double value to long int.
2 Copyright (C) 1997-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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.
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.
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/>. */
23 #include <math_private.h>
24 #include <libm-alias-double.h>
25 #include <fix-fp-int-convert-overflow.h>
27 /* For LP64, lround is an alias for llround. */
38 EXTRACT_WORDS64 (i0
, x
);
39 j0
= ((i0
>> 52) & 0x7ff) - 0x3ff;
40 sign
= i0
< 0 ? -1 : 1;
41 i0
&= UINT64_C(0xfffffffffffff);
42 i0
|= UINT64_C(0x10000000000000);
44 if (j0
< (int32_t) (8 * sizeof (long int)) - 1)
47 return j0
< -1 ? 0 : sign
;
49 result
= i0
<< (j0
- 52);
52 i0
+= UINT64_C(0x8000000000000) >> j0
;
54 result
= i0
>> (52 - j0
);
56 if (sizeof (long int) == 4
58 && result
== LONG_MIN
)
59 /* Rounding brought the value out of range. */
60 feraiseexcept (FE_INVALID
);
66 /* The number is too large. Unless it rounds to LONG_MIN,
67 FE_INVALID must be raised and the return value is
70 if (FIX_DBL_LONG_CONVERT_OVERFLOW
72 && (sizeof (long int) == 4
73 ? x
> (double) LONG_MIN
- 0.5
74 : x
>= (double) LONG_MIN
)))
76 feraiseexcept (FE_INVALID
);
77 return sign
== 1 ? LONG_MAX
: LONG_MIN
;
79 else if (!FIX_DBL_LONG_CONVERT_OVERFLOW
80 && sizeof (long int) == 4
81 && x
<= (double) LONG_MIN
- 0.5)
83 /* If truncation produces LONG_MIN, the cast will not raise
84 the exception, but may raise "inexact". */
85 feraiseexcept (FE_INVALID
);
95 libm_alias_double (__lround
, lround
)