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99d8158635
git-svn-id: file:///srv/svn/repos/haiku/buildtools/trunk@29042 a95241bf-73f2-0310-859d-f6bbb57e9c96
64 lines
1.8 KiB
C
64 lines
1.8 KiB
C
/* mpfr_get_ui -- convert a floating-point number to an unsigned long.
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Copyright 2003, 2004, 2006, 2007 Free Software Foundation, Inc.
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Contributed by the Arenaire and Cacao projects, INRIA.
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This file is part of the MPFR Library.
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The MPFR Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or (at your
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option) any later version.
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The MPFR Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the MPFR Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include "mpfr-impl.h"
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unsigned long
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mpfr_get_ui (mpfr_srcptr f, mp_rnd_t rnd)
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{
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mp_prec_t prec;
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unsigned long s;
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mpfr_t x;
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mp_size_t n;
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mp_exp_t exp;
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if (!mpfr_fits_ulong_p (f, rnd))
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{
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MPFR_SET_ERANGE ();
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return MPFR_IS_NEG (f) ? 0 : ULONG_MAX;
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}
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if (MPFR_IS_ZERO (f))
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return (unsigned long) 0;
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for (s = ULONG_MAX, prec = 0; s != 0; s >>= 1, prec ++);
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/* first round to prec bits */
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mpfr_init2 (x, prec);
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mpfr_rint (x, f, rnd);
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/* warning: if x=0, taking its exponent is illegal */
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if (MPFR_IS_ZERO(x))
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s = 0;
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else
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{
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/* now the result is in the most significant limb of x */
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exp = MPFR_GET_EXP (x); /* since |x| >= 1, exp >= 1 */
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n = MPFR_LIMB_SIZE(x);
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s = MPFR_MANT(x)[n - 1] >> (BITS_PER_MP_LIMB - exp);
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}
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mpfr_clear (x);
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return s;
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}
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