Copyright 1991, 1993, 1994, 1996, 2000, 2001, 2002 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 http://www.gnu.org/licenses/. */
#include "gmp.h"
#include "gmp-impl.h"
and store the n least significant limbs of the result at rp.
Return the bits shifted out from the most significant limb.
Argument constraints:
1. 0 < cnt < GMP_NUMB_BITS.
2. If the result is to be written over the input, rp must be >= up.
*/
mp_limb_t
mpn_lshift (mp_ptr rp, mp_srcptr up, mp_size_t n, unsigned int cnt)
{
mp_limb_t high_limb, low_limb;
unsigned int tnc;
mp_size_t i;
mp_limb_t retval;
ASSERT (n >= 1);
ASSERT (cnt >= 1);
ASSERT (cnt < GMP_NUMB_BITS);
ASSERT (MPN_SAME_OR_DECR_P (rp, up, n));
up += n;
rp += n;
tnc = GMP_NUMB_BITS - cnt;
low_limb = *--up;
retval = low_limb >> tnc;
high_limb = (low_limb << cnt) & GMP_NUMB_MASK;
for (i = n - 1; i != 0; i--)
{
low_limb = *--up;
*--rp = high_limb | (low_limb >> tnc);
high_limb = (low_limb << cnt) & GMP_NUMB_MASK;
}
*--rp = high_limb;
return retval;
}
