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/* mpz_tdiv_r_2exp -- Divide an integer by 2**CNT and produce a remainder.
Copyright 1991, 1993-1995, 2001, 2002, 2012 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 3 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. If not, see https://www.gnu.org/licenses/. */
#include "gmp.h"
#include "gmp-impl.h"
void
mpz_tdiv_r_2exp (mpz_ptr res, mpz_srcptr in, mp_bitcnt_t cnt)
{
mp_size_t in_size = ABSIZ (in);
mp_size_t res_size;
mp_size_t limb_cnt = cnt / GMP_NUMB_BITS;
mp_srcptr in_ptr = PTR (in);
if (in_size > limb_cnt)
{
/* The input operand is (probably) greater than 2**CNT. */
mp_limb_t x;
x = in_ptr[limb_cnt] & (((mp_limb_t) 1 << cnt % GMP_NUMB_BITS) - 1);
if (x != 0)
{
res_size = limb_cnt + 1;
MPZ_REALLOC (res, res_size);
PTR (res)[limb_cnt] = x;
}
else
{
res_size = limb_cnt;
MPN_NORMALIZE (in_ptr, res_size);
MPZ_REALLOC (res, res_size);
limb_cnt = res_size;
}
}
else
{
/* The input operand is smaller than 2**CNT. We perform a no-op,
apart from that we might need to copy IN to RES. */
res_size = in_size;
MPZ_REALLOC (res, res_size);
limb_cnt = res_size;
}
if (res != in)
MPN_COPY (PTR (res), PTR (in), limb_cnt);
SIZ (res) = SIZ (in) >= 0 ? res_size : -res_size;
}
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