1 /* Round argument to nearest integral value according to current rounding
3 Copyright (C) 1997-2019 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public
9 License as published by the Free Software Foundation; either
10 version 2.1 of the License, or (at your option) any later version.
12 The GNU C Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library; if not, see
19 <https://www.gnu.org/licenses/>. */
25 #include <math-narrow-eval.h>
26 #include <math_private.h>
27 #include <libm-alias-double.h>
28 #include <fix-fp-int-convert-overflow.h>
30 static const double two52
[2] =
32 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
33 -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
47 EXTRACT_WORDS (i0
, i1
, x
);
48 j0
= ((i0
>> 20) & 0x7ff) - 0x3ff;
55 w
= math_narrow_eval (two52
[sx
] + x
);
57 EXTRACT_WORDS (i0
, i1
, t
);
58 j0
= ((i0
>> 20) & 0x7ff) - 0x3ff;
62 result
= (j0
< 0 ? 0 : i0
>> (20 - j0
));
64 else if (j0
< (int32_t) (8 * sizeof (long int)) - 1)
67 result
= ((long int) i0
<< (j0
- 20)) | ((long int) i1
<< (j0
- 52));
70 #if defined FE_INVALID || defined FE_INEXACT
71 /* X < LONG_MAX + 1 implied by J0 < 31. */
72 if (sizeof (long int) == 4
73 && x
> (double) LONG_MAX
)
75 /* In the event of overflow we must raise the "invalid"
76 exception, but not "inexact". */
78 feraiseexcept (t
== LONG_MAX
? FE_INEXACT
: FE_INVALID
);
83 w
= math_narrow_eval (two52
[sx
] + x
);
86 EXTRACT_WORDS (i0
, i1
, t
);
87 j0
= ((i0
>> 20) & 0x7ff) - 0x3ff;
92 result
= (long int) i0
;
94 result
= ((long int) i0
<< (j0
- 20)) | (i1
>> (52 - j0
));
99 /* The number is too large. Unless it rounds to LONG_MIN,
100 FE_INVALID must be raised and the return value is
102 #if defined FE_INVALID || defined FE_INEXACT
103 if (sizeof (long int) == 4
104 && x
< (double) LONG_MIN
105 && x
> (double) LONG_MIN
- 1.0)
107 /* If truncation produces LONG_MIN, the cast will not raise
108 the exception, but may raise "inexact". */
110 feraiseexcept (t
== LONG_MIN
? FE_INEXACT
: FE_INVALID
);
113 else if (FIX_DBL_LONG_CONVERT_OVERFLOW
&& x
!= (double) LONG_MIN
)
115 feraiseexcept (FE_INVALID
);
116 return sx
== 0 ? LONG_MAX
: LONG_MIN
;
122 return sx
? -result
: result
;
125 libm_alias_double (__lrint
, lrint
)