Blame mpz/tdiv_q.c

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/* mpz_tdiv_q -- divide two integers and produce a quotient.
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Copyright 1991, 1993, 1994, 1996, 2000, 2001, 2005, 2010, 2012 Free Software
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Foundation, Inc.
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This file is part of the GNU MP Library.
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The GNU MP Library is free software; you can redistribute it and/or modify
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it under the terms of either:
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  * the GNU Lesser General Public License as published by the Free
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    Software Foundation; either version 3 of the License, or (at your
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    option) any later version.
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or
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  * the GNU General Public License as published by the Free Software
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    Foundation; either version 2 of the License, or (at your option) any
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    later version.
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or both in parallel, as here.
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The GNU MP 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 General Public License
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for more details.
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You should have received copies of the GNU General Public License and the
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GNU Lesser General Public License along with the GNU MP Library.  If not,
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see https://www.gnu.org/licenses/.  */
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#include "gmp.h"
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#include "gmp-impl.h"
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#include "longlong.h"
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void
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mpz_tdiv_q (mpz_ptr quot, mpz_srcptr num, mpz_srcptr den)
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{
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  mp_size_t ql;
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  mp_size_t ns, ds, nl, dl;
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  mp_ptr np, dp, qp;
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  TMP_DECL;
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  ns = SIZ (num);
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  ds = SIZ (den);
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  nl = ABS (ns);
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  dl = ABS (ds);
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  ql = nl - dl + 1;
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  if (UNLIKELY (dl == 0))
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    DIVIDE_BY_ZERO;
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  if (ql <= 0)
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    {
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      SIZ (quot) = 0;
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      return;
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    }
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  qp = MPZ_REALLOC (quot, ql);
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  TMP_MARK;
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  np = PTR (num);
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  dp = PTR (den);
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  /* Copy denominator to temporary space if it overlaps with the quotient.  */
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  if (dp == qp)
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    {
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      mp_ptr tp;
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      tp = TMP_ALLOC_LIMBS (dl);
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      MPN_COPY (tp, dp, dl);
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      dp = tp;
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    }
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  /* Copy numerator to temporary space if it overlaps with the quotient.  */
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  if (np == qp)
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    {
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      mp_ptr tp;
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      tp = TMP_ALLOC_LIMBS (nl + 1);
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      MPN_COPY (tp, np, nl);
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      /* Overlap dividend and scratch.  */
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      mpn_div_q (qp, tp, nl, dp, dl, tp);
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    }
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  else
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    {
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      mp_ptr tp;
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      tp = TMP_ALLOC_LIMBS (nl + 1);
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      mpn_div_q (qp, np, nl, dp, dl, tp);
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    }
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  ql -=  qp[ql - 1] == 0;
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  SIZ (quot) = (ns ^ ds) >= 0 ? ql : -ql;
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  TMP_FREE;
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}