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61 lines
1.6 KiB
C
61 lines
1.6 KiB
C
/* Truncate argument to nearest integral value not larger than the argument.
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Copyright (C) 1997-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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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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double
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__trunc (double x)
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{
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int32_t i0, j0;
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u_int32_t i1;
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int sx;
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EXTRACT_WORDS (i0, i1, x);
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sx = i0 & 0x80000000;
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j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
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if (j0 < 20)
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{
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if (j0 < 0)
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/* The magnitude of the number is < 1 so the result is +-0. */
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INSERT_WORDS (x, sx, 0);
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else
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INSERT_WORDS (x, sx | (i0 & ~(0x000fffff >> j0)), 0);
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}
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else if (j0 > 51)
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{
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if (j0 == 0x400)
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/* x is inf or NaN. */
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return x + x;
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}
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else
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{
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INSERT_WORDS (x, i0, i1 & ~(0xffffffffu >> (j0 - 20)));
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}
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return x;
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}
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weak_alias (__trunc, trunc)
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#ifdef NO_LONG_DOUBLE
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strong_alias (__trunc, __truncl)
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weak_alias (__trunc, truncl)
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#endif
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