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/*
Copyright (C) 2010 Fredrik Johansson
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "mpn_extras.h"
mp_size_t flint_mpn_remove_2exp(mp_ptr x, mp_size_t xsize, flint_bitcnt_t *bits)
{
mp_size_t shift_limbs, reduced_size;
flint_bitcnt_t shift_bits;
*bits = mpn_scan1(x, 0);
if (*bits == 0)
return xsize;
shift_limbs = *bits / FLINT_BITS;
shift_bits = *bits % FLINT_BITS;
reduced_size = xsize - shift_limbs;
if (shift_bits)
{
mpn_rshift(x, x + shift_limbs, reduced_size, shift_bits);
if (x[reduced_size - 1] == 0)
reduced_size -= 1;
}
else
{
flint_mpn_copyi(x, x + shift_limbs, reduced_size);
}
return reduced_size;
}