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61 lines
2.0 KiB
C
61 lines
2.0 KiB
C
/* Set NaN payload. ldbl-128ibm version.
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Copyright (C) 2016-2020 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <math.h>
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#include <math_private.h>
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#include <nan-high-order-bit.h>
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#include <stdint.h>
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#define SET_HIGH_BIT (HIGH_ORDER_BIT_IS_SET_FOR_SNAN ? SIG : !SIG)
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#define BIAS 0x3ff
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#define PAYLOAD_DIG 51
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#define EXPLICIT_MANT_DIG 52
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int
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FUNC (long double *x, long double payload)
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{
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double hi, lo;
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uint64_t hx, lx;
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ldbl_unpack (payload, &hi, &lo);
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EXTRACT_WORDS64 (hx, hi);
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EXTRACT_WORDS64 (lx, lo);
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int exponent = hx >> EXPLICIT_MANT_DIG;
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/* Test if argument is (a) negative or too large; (b) too small,
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except for 0 when allowed; (c) not an integer. All valid
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arguments have the low part zero. */
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if ((lx & 0x7fffffffffffffffULL) != 0
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|| exponent >= BIAS + PAYLOAD_DIG
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|| (exponent < BIAS && !(SET_HIGH_BIT && hx == 0))
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|| (hx & ((1ULL << (BIAS + EXPLICIT_MANT_DIG - exponent)) - 1)) != 0)
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{
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*x = 0.0L;
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return 1;
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}
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if (hx != 0)
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{
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hx &= (1ULL << EXPLICIT_MANT_DIG) - 1;
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hx |= 1ULL << EXPLICIT_MANT_DIG;
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hx >>= BIAS + EXPLICIT_MANT_DIG - exponent;
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}
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hx |= 0x7ff0000000000000ULL | (SET_HIGH_BIT ? 0x8000000000000ULL : 0);
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INSERT_WORDS64 (hi, hx);
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*x = ldbl_pack (hi, 0.0);
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return 0;
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}
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