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* All files with FSF copyright notices: Update copyright dates using scripts/update-copyrights. * locale/programs/charmap-kw.h: Regenerated. * locale/programs/locfile-kw.h: Likewise.
61 lines
2.0 KiB
C
61 lines
2.0 KiB
C
/* Test whether long double value is canonical. ldbl-128ibm version.
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Copyright (C) 2016-2018 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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<http://www.gnu.org/licenses/>. */
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#include <math.h>
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#include <math_private.h>
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#include <stdint.h>
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int
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__iscanonicall (long double x)
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{
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double xhi, xlo;
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uint64_t hx, lx;
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ldbl_unpack (x, &xhi, &xlo);
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EXTRACT_WORDS64 (hx, xhi);
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EXTRACT_WORDS64 (lx, xlo);
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int64_t ix = hx & 0x7fffffffffffffffULL;
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int64_t iy = lx & 0x7fffffffffffffffULL;
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int hexp = (ix & 0x7ff0000000000000LL) >> 52;
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int lexp = (iy & 0x7ff0000000000000LL) >> 52;
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if (iy == 0)
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/* Low part 0 is always OK. */
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return 1;
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if (hexp == 0x7ff)
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/* If a NaN, the low part does not matter. If an infinity, the
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low part must be 0, in which case we have already returned. */
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return ix != 0x7ff0000000000000LL;
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/* The high part is finite and the low part is nonzero. There must
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be sufficient difference between the exponents. */
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bool low_p2;
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if (lexp == 0)
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{
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/* Adjust the exponent for subnormal low part. */
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lexp = 12 - __builtin_clzll (iy);
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low_p2 = iy == (1LL << (51 + lexp));
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}
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else
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low_p2 = (iy & 0xfffffffffffffLL) == 0;
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int expdiff = hexp - lexp;
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return expdiff > 53 || (expdiff == 53 && low_p2 && (ix & 1) == 0);
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}
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libm_hidden_def (__iscanonicall)
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