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git.ipfire.org Git - thirdparty/glibc.git/blob - sysdeps/ieee754/ldbl-128/s_issignalingl.c
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1 /* Test for signaling NaN.
2 Copyright (C) 2013-2016 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 <http://www.gnu.org/licenses/>. */
20 #include <math_private.h>
21 #include <nan-high-order-bit.h>
24 __issignalingl (_Float128 x
)
26 u_int64_t hxi
, lxi
__attribute__ ((unused
));
27 GET_LDOUBLE_WORDS64 (hxi
, lxi
, x
);
28 #if HIGH_ORDER_BIT_IS_SET_FOR_SNAN
29 /* We only have to care about the high-order bit of x's significand, because
30 having it set (sNaN) already makes the significand different from that
31 used to designate infinity. */
32 return ((hxi
& UINT64_C (0x7fff800000000000))
33 == UINT64_C (0x7fff800000000000));
35 /* To keep the following comparison simple, toggle the quiet/signaling bit,
36 so that it is set for sNaNs. This is inverse to IEEE 754-2008 (as well as
37 common practice for IEEE 754-1985). */
38 hxi
^= UINT64_C (0x0000800000000000);
39 /* If lxi != 0, then set any suitable bit of the significand in hxi. */
40 hxi
|= (lxi
| -lxi
) >> 63;
41 /* We have to compare for greater (instead of greater or equal), because x's
42 significand being all-zero designates infinity not NaN. */
43 return (hxi
& UINT64_C (0x7fffffffffffffff)) > UINT64_C (0x7fff800000000000);
46 libm_hidden_def (__issignalingl
)