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112 lines
2.6 KiB
C
112 lines
2.6 KiB
C
/* Round long double value to long int.
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Copyright (C) 1997-2017 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 <fenv.h>
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#include <limits.h>
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#include <math.h>
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#include <math_private.h>
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long int
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__lroundl (long double x)
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{
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int32_t j0;
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u_int32_t se, i1, i0;
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long int result;
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int sign;
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GET_LDOUBLE_WORDS (se, i0, i1, x);
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j0 = (se & 0x7fff) - 0x3fff;
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sign = (se & 0x8000) != 0 ? -1 : 1;
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if (j0 < 31)
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{
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if (j0 < 0)
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return j0 < -1 ? 0 : sign;
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else
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{
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u_int32_t j = i0 + (0x40000000 >> j0);
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if (j < i0)
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{
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j >>= 1;
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j |= 0x80000000;
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++j0;
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}
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result = j >> (31 - j0);
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#ifdef FE_INVALID
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if (sizeof (long int) == 4
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&& sign == 1
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&& result == LONG_MIN)
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/* Rounding brought the value out of range. */
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feraiseexcept (FE_INVALID);
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#endif
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}
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}
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else if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
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{
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if (j0 >= 63)
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result = ((long int) i0 << (j0 - 31)) | (i1 << (j0 - 63));
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else
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{
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u_int32_t j = i1 + (0x80000000 >> (j0 - 31));
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unsigned long int ures = i0;
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if (j < i1)
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++ures;
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if (j0 == 31)
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result = ures;
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else
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{
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result = (ures << (j0 - 31)) | (j >> (63 - j0));
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#ifdef FE_INVALID
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if (sizeof (long int) == 8
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&& sign == 1
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&& result == LONG_MIN)
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/* Rounding brought the value out of range. */
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feraiseexcept (FE_INVALID);
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#endif
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}
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}
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}
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else
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{
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/* The number is too large. Unless it rounds to LONG_MIN,
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FE_INVALID must be raised and the return value is
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unspecified. */
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#ifdef FE_INVALID
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if (sizeof (long int) == 4
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&& x <= (long double) LONG_MIN - 0.5L)
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{
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/* If truncation produces LONG_MIN, the cast will not raise
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the exception, but may raise "inexact". */
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feraiseexcept (FE_INVALID);
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return LONG_MIN;
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}
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#endif
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return (long int) x;
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}
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return sign * result;
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}
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weak_alias (__lroundl, lroundl)
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