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1 /* Test for signaling NaN.
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2 Copyright (C) 2013-2018 Free Software Foundation, Inc.
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3 This file is part of the GNU C Library.
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4
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5 The GNU C Library is free software; you can redistribute it and/or
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6 modify it under the terms of the GNU Lesser General Public
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7 License as published by the Free Software Foundation; either
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8 version 2.1 of the License, or (at your option) any later version.
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9
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10 The GNU C Library is distributed in the hope that it will be useful,
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 Lesser General Public License for more details.
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14
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15 You should have received a copy of the GNU Lesser General Public
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16 License along with the GNU C Library; if not, see
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17 <http://www.gnu.org/licenses/>. */
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18
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19 #include "quadmath-imp.h"
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20
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21 int
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22 issignalingq (__float128 x)
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23 {
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24 uint64_t hxi, lxi __attribute__ ((unused));
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25 GET_FLT128_WORDS64 (hxi, lxi, x);
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26 #if HIGH_ORDER_BIT_IS_SET_FOR_SNAN
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27 /* We only have to care about the high-order bit of x's significand, because
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28 having it set (sNaN) already makes the significand different from that
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29 used to designate infinity. */
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30 return ((hxi & UINT64_C (0x7fff800000000000))
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31 == UINT64_C (0x7fff800000000000));
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32 #else
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33 /* To keep the following comparison simple, toggle the quiet/signaling bit,
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34 so that it is set for sNaNs. This is inverse to IEEE 754-2008 (as well as
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35 common practice for IEEE 754-1985). */
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36 hxi ^= UINT64_C (0x0000800000000000);
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37 /* If lxi != 0, then set any suitable bit of the significand in hxi. */
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38 hxi |= (lxi | -lxi) >> 63;
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39 /* We have to compare for greater (instead of greater or equal), because x's
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40 significand being all-zero designates infinity not NaN. */
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41 return (hxi & UINT64_C (0x7fffffffffffffff)) > UINT64_C (0x7fff800000000000);
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42 #endif
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43 }
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