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https://review.haiku-os.org/buildtools
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b58ddff026
* merged mpfr 3.0.0 and gmp 5.0.1 in buildtools trunk git-svn-id: file:///srv/svn/repos/haiku/buildtools/trunk@37378 a95241bf-73f2-0310-859d-f6bbb57e9c96
134 lines
3.4 KiB
C
134 lines
3.4 KiB
C
/* mpfr_set_q -- set a floating-point number from a multiple-precision rational
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Copyright 2000, 2001, 2002, 2004, 2005, 2006, 2007, 2008, 2009, 2010 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 GNU MPFR Library.
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The GNU 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 3 of the License, or (at your
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option) any later version.
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The GNU 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 GNU MPFR Library; see the file COPYING.LESSER. If not, see
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http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
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51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
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#define MPFR_NEED_LONGLONG_H
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#include "mpfr-impl.h"
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/*
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* Set f to z, choosing the smallest precision for f
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* so that z = f*(2^BPML)*zs*2^(RetVal)
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*/
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static int
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set_z (mpfr_ptr f, mpz_srcptr z, mp_size_t *zs)
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{
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mp_limb_t *p;
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mp_size_t s;
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int c;
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mpfr_prec_t pf;
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MPFR_ASSERTD (mpz_sgn (z) != 0);
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/* Remove useless ending 0 */
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for (p = PTR (z), s = *zs = ABS (SIZ (z)) ; *p == 0; p++, s--)
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MPFR_ASSERTD (s >= 0);
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/* Get working precision */
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count_leading_zeros (c, p[s-1]);
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pf = s * GMP_NUMB_BITS - c;
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if (pf < MPFR_PREC_MIN)
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pf = MPFR_PREC_MIN;
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mpfr_init2 (f, pf);
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/* Copy Mantissa */
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if (MPFR_LIKELY (c))
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mpn_lshift (MPFR_MANT (f), p, s, c);
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else
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MPN_COPY (MPFR_MANT (f), p, s);
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MPFR_SET_SIGN (f, mpz_sgn (z));
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MPFR_SET_EXP (f, 0);
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return -c;
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}
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/* set f to the rational q */
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int
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mpfr_set_q (mpfr_ptr f, mpq_srcptr q, mpfr_rnd_t rnd)
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{
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mpz_srcptr num, den;
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mpfr_t n, d;
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int inexact;
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int cn, cd;
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long shift;
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mp_size_t sn, sd;
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MPFR_SAVE_EXPO_DECL (expo);
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num = mpq_numref (q);
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den = mpq_denref (q);
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/* NAN and INF for mpq are not really documented, but could be found */
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if (MPFR_UNLIKELY (mpz_sgn (num) == 0))
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{
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if (MPFR_UNLIKELY (mpz_sgn (den) == 0))
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{
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MPFR_SET_NAN (f);
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MPFR_RET_NAN;
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}
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else
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{
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MPFR_SET_ZERO (f);
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MPFR_SET_POS (f);
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MPFR_RET (0);
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}
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}
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if (MPFR_UNLIKELY (mpz_sgn (den) == 0))
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{
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MPFR_SET_INF (f);
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MPFR_SET_SIGN (f, mpz_sgn (num));
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MPFR_RET (0);
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}
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MPFR_SAVE_EXPO_MARK (expo);
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cn = set_z (n, num, &sn);
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cd = set_z (d, den, &sd);
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sn -= sd;
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if (MPFR_UNLIKELY (sn > MPFR_EMAX_MAX / GMP_NUMB_BITS))
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{
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inexact = mpfr_overflow (f, rnd, MPFR_SIGN (f));
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goto end;
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}
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if (MPFR_UNLIKELY (sn < MPFR_EMIN_MIN / GMP_NUMB_BITS -1))
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{
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if (rnd == MPFR_RNDN)
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rnd = MPFR_RNDZ;
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inexact = mpfr_underflow (f, rnd, MPFR_SIGN (f));
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goto end;
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}
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inexact = mpfr_div (f, n, d, rnd);
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shift = GMP_NUMB_BITS*sn+cn-cd;
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MPFR_ASSERTD (shift == GMP_NUMB_BITS*sn+cn-cd);
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cd = mpfr_mul_2si (f, f, shift, rnd);
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MPFR_SAVE_EXPO_FREE (expo);
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if (MPFR_UNLIKELY (cd != 0))
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inexact = cd;
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else
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inexact = mpfr_check_range (f, inexact, rnd);
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end:
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mpfr_clear (d);
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mpfr_clear (n);
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return inexact;
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}
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