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57267616 | 1 | /* Test for signaling NaN. |
04277e02 | 2 | Copyright (C) 2013-2019 Free Software Foundation, Inc. |
57267616 TS |
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 | <http://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #include <math.h> | |
20 | #include <math_private.h> | |
6f322a89 | 21 | #include <nan-high-order-bit.h> |
57267616 TS |
22 | |
23 | int | |
24 | __issignaling (double x) | |
25 | { | |
6f322a89 | 26 | #if HIGH_ORDER_BIT_IS_SET_FOR_SNAN |
24ab7723 | 27 | uint32_t hxi; |
57267616 TS |
28 | GET_HIGH_WORD (hxi, x); |
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 & 0x7ff80000) == 0x7ff80000; | |
33 | #else | |
24ab7723 | 34 | uint32_t hxi, lxi; |
57267616 TS |
35 | EXTRACT_WORDS (hxi, lxi, x); |
36 | /* To keep the following comparison simple, toggle the quiet/signaling bit, | |
37 | so that it is set for sNaNs. This is inverse to IEEE 754-2008 (as well as | |
38 | common practice for IEEE 754-1985). */ | |
39 | hxi ^= 0x00080000; | |
40 | /* If lxi != 0, then set any suitable bit of the significand in hxi. */ | |
41 | hxi |= (lxi | -lxi) >> 31; | |
42 | /* We have to compare for greater (instead of greater or equal), because x's | |
43 | significand being all-zero designates infinity not NaN. */ | |
44 | return (hxi & 0x7fffffff) > 0x7ff80000; | |
45 | #endif | |
46 | } | |
47 | libm_hidden_def (__issignaling) |