1 | /* Test for signaling NaN. |
2 | Copyright (C) 2013-2022 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | |
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. |
9 | |
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. |
14 | |
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/>. */ |
18 | |
19 | #include <math.h> |
20 | #include <math_private.h> |
21 | #include <nan-high-order-bit.h> |
22 | |
23 | int |
24 | __issignalingl (long double x) |
25 | { |
26 | uint64_t xi; |
27 | /* For inspecting NaN status, we only have to look at the first of the pair |
28 | of IEEE 754 64-bit precision numbers. */ |
29 | double xhi; |
30 | |
31 | xhi = ldbl_high (x); |
32 | EXTRACT_WORDS64 (xi, xhi); |
33 | #if HIGH_ORDER_BIT_IS_SET_FOR_SNAN |
34 | # error untested |
35 | /* We only have to care about the high-order bit of x's significand, because |
36 | having it set (sNaN) already makes the significand different from that |
37 | used to designate infinity. */ |
38 | return (xi & UINT64_C (0x7ff8000000000000)) == UINT64_C (0x7ff8000000000000); |
39 | #else |
40 | /* To keep the following comparison simple, toggle the quiet/signaling bit, |
41 | so that it is set for sNaNs. This is inverse to IEEE 754-2008 (as well as |
42 | common practice for IEEE 754-1985). */ |
43 | xi ^= UINT64_C (0x0008000000000000); |
44 | /* We have to compare for greater (instead of greater or equal), because x's |
45 | significand being all-zero designates infinity not NaN. */ |
46 | return (xi & UINT64_C (0x7fffffffffffffff)) > UINT64_C (0x7ff8000000000000); |
47 | #endif |
48 | } |
49 | libm_hidden_def (__issignalingl) |
50 | |