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/* mpz_tdiv_q_2exp -- Divide an integer by 2**CNT. Round the quotient
towards -infinity.
Copyright (C) 1991, 1993, 1994, 1996 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 Library General Public License as published by
the Free Software Foundation; either version 2 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 Library General Public
License for more details.
You should have received a copy of the GNU Library General Public License
along with the GNU MP Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */
#include "gmp.h"
#include "gmp-impl.h"
void
#if __STDC__
mpz_tdiv_q_2exp (mpz_ptr w, mpz_srcptr u, unsigned long int cnt)
#else
mpz_tdiv_q_2exp (w, u, cnt)
mpz_ptr w;
mpz_srcptr u;
unsigned long int cnt;
#endif
{
mp_size_t usize, wsize;
mp_size_t limb_cnt;
usize = u->_mp_size;
limb_cnt = cnt / BITS_PER_MP_LIMB;
wsize = ABS (usize) - limb_cnt;
if (wsize <= 0)
w->_mp_size = 0;
else
{
mp_ptr wp;
mp_srcptr up;
if (w->_mp_alloc < wsize)
_mpz_realloc (w, wsize);
wp = w->_mp_d;
up = u->_mp_d;
cnt %= BITS_PER_MP_LIMB;
if (cnt != 0)
{
mpn_rshift (wp, up + limb_cnt, wsize, cnt);
wsize -= wp[wsize - 1] == 0;
}
else
{
MPN_COPY_INCR (wp, up + limb_cnt, wsize);
}
w->_mp_size = usize >= 0 ? wsize : -wsize;
}
}
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