1 /* Round argument to nearest integral value according to current rounding
3 Copyright (C) 1997-2023 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
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.
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.
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/>. */
24 #include <math-narrow-eval.h>
25 #include <math_private.h>
26 #include <libm-alias-double.h>
27 #include <fix-fp-int-convert-overflow.h>
28 #include <math-use-builtins.h>
35 return __builtin_lrint (x
);
37 /* Use generic implementation. */
38 static const double two52
[2] =
40 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
41 -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
51 EXTRACT_WORDS (i0
, i1
, x
);
52 j0
= ((i0
>> 20) & 0x7ff) - 0x3ff;
59 w
= math_narrow_eval (two52
[sx
] + x
);
61 EXTRACT_WORDS (i0
, i1
, t
);
62 j0
= ((i0
>> 20) & 0x7ff) - 0x3ff;
66 result
= (j0
< 0 ? 0 : i0
>> (20 - j0
));
68 else if (j0
< (int32_t) (8 * sizeof (long int)) - 1)
71 result
= ((long int) i0
<< (j0
- 20)) | ((long int) i1
<< (j0
- 52));
74 #if defined FE_INVALID || defined FE_INEXACT
75 /* X < LONG_MAX + 1 implied by J0 < 31. */
76 if (sizeof (long int) == 4
77 && x
> (double) LONG_MAX
)
79 /* In the event of overflow we must raise the "invalid"
80 exception, but not "inexact". */
82 feraiseexcept (t
== LONG_MAX
? FE_INEXACT
: FE_INVALID
);
87 w
= math_narrow_eval (two52
[sx
] + x
);
90 EXTRACT_WORDS (i0
, i1
, t
);
91 j0
= ((i0
>> 20) & 0x7ff) - 0x3ff;
96 result
= (long int) i0
;
98 result
= ((long int) i0
<< (j0
- 20)) | (i1
>> (52 - j0
));
103 /* The number is too large. Unless it rounds to LONG_MIN,
104 FE_INVALID must be raised and the return value is
106 #if defined FE_INVALID || defined FE_INEXACT
107 if (sizeof (long int) == 4
108 && x
< (double) LONG_MIN
109 && x
> (double) LONG_MIN
- 1.0)
111 /* If truncation produces LONG_MIN, the cast will not raise
112 the exception, but may raise "inexact". */
114 feraiseexcept (t
== LONG_MIN
? FE_INEXACT
: FE_INVALID
);
117 else if (FIX_DBL_LONG_CONVERT_OVERFLOW
&& x
!= (double) LONG_MIN
)
119 feraiseexcept (FE_INVALID
);
120 return sx
== 0 ? LONG_MAX
: LONG_MIN
;
126 return sx
? -result
: result
;
127 #endif /* ! USE_LRINT_BUILTIN */
130 libm_alias_double (__lrint
, lrint
)