e554550755
for file in $(find -name \*.h ) ; do sed -e "s/#include \"gmp\.h\"/#include \"mpir.h\"/g" $file > temp ; mv temp $file ; done for file in $(find -name \*.cc) ; do sed -e "s/#include \"gmp\.h\"/#include \"mpir.h\"/g" $file > temp ; mv temp $file ; done
136 lines
3.6 KiB
C
136 lines
3.6 KiB
C
/* mpz_divexact -- finds quotient when known that quot * den == num && den != 0.
|
|
|
|
Copyright 1991, 1993, 1994, 1995, 1996, 1997, 1998, 2000, 2001, 2002, 2005, 2006
|
|
Free Software Foundation, Inc.
|
|
|
|
This file is part of the GNU MP Library.
|
|
|
|
The GNU MP Library is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU Lesser General Public License as published by
|
|
the Free Software Foundation; either version 2.1 of the License, or (at your
|
|
option) any later version.
|
|
|
|
The GNU MP Library is distributed in the hope that it will be useful, but
|
|
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|
|
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
|
|
License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with the GNU MP Library; see the file COPYING.LIB. If not, write to
|
|
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
|
|
MA 02110-1301, USA. */
|
|
|
|
/* Ken Weber (kweber@mat.ufrgs.br, kweber@mcs.kent.edu)
|
|
|
|
Funding for this work has been partially provided by Conselho Nacional
|
|
de Desenvolvimento Cienti'fico e Tecnolo'gico (CNPq) do Brazil, Grant
|
|
301314194-2, and was done while I was a visiting reseacher in the Instituto
|
|
de Matema'tica at Universidade Federal do Rio Grande do Sul (UFRGS).
|
|
|
|
References:
|
|
T. Jebelean, An algorithm for exact division, Journal of Symbolic
|
|
Computation, v. 15, 1993, pp. 169-180. */
|
|
|
|
#include "mpir.h"
|
|
#include "gmp-impl.h"
|
|
#include "longlong.h"
|
|
|
|
void
|
|
mpz_divexact (mpz_ptr quot, mpz_srcptr num, mpz_srcptr den)
|
|
{
|
|
mp_ptr qp, tp;
|
|
mp_size_t qsize, tsize;
|
|
mp_srcptr np, dp;
|
|
mp_size_t nsize, dsize;
|
|
TMP_DECL;
|
|
|
|
#if WANT_ASSERT
|
|
{
|
|
mpz_t rem;
|
|
mpz_init (rem);
|
|
mpz_tdiv_r (rem, num, den);
|
|
ASSERT (SIZ(rem) == 0);
|
|
mpz_clear (rem);
|
|
}
|
|
#endif
|
|
|
|
nsize = ABS (num->_mp_size);
|
|
dsize = ABS (den->_mp_size);
|
|
|
|
qsize = nsize - dsize + 1;
|
|
if (quot->_mp_alloc < qsize)
|
|
_mpz_realloc (quot, qsize);
|
|
|
|
np = num->_mp_d;
|
|
dp = den->_mp_d;
|
|
qp = quot->_mp_d;
|
|
|
|
if (nsize == 0)
|
|
{
|
|
if (dsize == 0)
|
|
DIVIDE_BY_ZERO;
|
|
quot->_mp_size = 0;
|
|
return;
|
|
}
|
|
|
|
if (dsize <= 1)
|
|
{
|
|
if (dsize == 1)
|
|
{
|
|
MPN_DIVREM_OR_DIVEXACT_1 (qp, np, nsize, dp[0]);
|
|
qsize -= qp[qsize - 1] == 0;
|
|
quot->_mp_size = (num->_mp_size ^ den->_mp_size) >= 0 ? qsize : -qsize;
|
|
return;
|
|
}
|
|
|
|
/* Generate divide-by-zero error since dsize == 0. */
|
|
DIVIDE_BY_ZERO;
|
|
}
|
|
|
|
/* Avoid quadratic behaviour, but do it conservatively. */
|
|
if (qsize > 1500)
|
|
{
|
|
mpz_tdiv_q (quot, num, den);
|
|
return;
|
|
}
|
|
|
|
TMP_MARK;
|
|
|
|
/* QUOT <-- NUM/2^r, T <-- DEN/2^r where = r number of twos in DEN. */
|
|
while (dp[0] == 0)
|
|
np += 1, nsize -= 1, dp += 1, dsize -= 1;
|
|
tsize = MIN (qsize, dsize);
|
|
if ((dp[0] & 1) != 0)
|
|
{
|
|
if (quot == den) /* QUOT and DEN overlap. */
|
|
{
|
|
tp = (mp_ptr) TMP_ALLOC (tsize * BYTES_PER_MP_LIMB);
|
|
MPN_COPY (tp, dp, tsize);
|
|
}
|
|
else
|
|
tp = (mp_ptr) dp;
|
|
if (qp != np)
|
|
MPN_COPY_INCR (qp, np, qsize);
|
|
}
|
|
else
|
|
{
|
|
unsigned int r;
|
|
tp = (mp_ptr) TMP_ALLOC (tsize * BYTES_PER_MP_LIMB);
|
|
count_trailing_zeros (r, dp[0]);
|
|
mpn_rshift (tp, dp, tsize, r);
|
|
if (dsize > tsize)
|
|
tp[tsize - 1] |= (dp[tsize] << (GMP_NUMB_BITS - r)) & GMP_NUMB_MASK;
|
|
mpn_rshift (qp, np, qsize, r);
|
|
if (nsize > qsize)
|
|
qp[qsize - 1] |= (np[qsize] << (GMP_NUMB_BITS - r)) & GMP_NUMB_MASK;
|
|
}
|
|
|
|
/* Now QUOT <-- QUOT/T. */
|
|
mpn_bdivmod (qp, qp, qsize, tp, tsize, qsize * GMP_NUMB_BITS);
|
|
MPN_NORMALIZE (qp, qsize);
|
|
|
|
quot->_mp_size = (num->_mp_size ^ den->_mp_size) >= 0 ? qsize : -qsize;
|
|
|
|
TMP_FREE;
|
|
}
|