1 /* mpz_tdiv_r_2exp -- Divide a integer by 2**CNT and produce a remainder.
3 Copyright (C) 1991, 1993, 1994, 1995 Free Software Foundation, Inc.
5 This file is part of the GNU MP Library.
7 The GNU MP Library is free software; you can redistribute it and/or modify
8 it under the terms of the GNU Library General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or (at your
10 option) any later version.
12 The GNU MP Library is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
15 License for more details.
17 You should have received a copy of the GNU Library General Public License
18 along with the GNU MP Library; see the file COPYING.LIB. If not, write to
19 the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
20 MA 02111-1307, USA. */
27 mpz_tdiv_r_2exp (mpz_ptr res, mpz_srcptr in, unsigned long int cnt)
29 mpz_tdiv_r_2exp (res, in, cnt)
32 unsigned long int cnt;
35 mp_size_t in_size = ABS (in->_mp_size);
37 mp_size_t limb_cnt = cnt / BITS_PER_MP_LIMB;
38 mp_srcptr in_ptr = in->_mp_d;
40 if (in_size > limb_cnt)
42 /* The input operand is (probably) greater than 2**CNT. */
45 x = in_ptr[limb_cnt] & (((mp_limb_t) 1 << cnt % BITS_PER_MP_LIMB) - 1);
48 res_size = limb_cnt + 1;
49 if (res->_mp_alloc < res_size)
50 _mpz_realloc (res, res_size);
52 res->_mp_d[limb_cnt] = x;
57 MPN_NORMALIZE (in_ptr, res_size);
59 if (res->_mp_alloc < res_size)
60 _mpz_realloc (res, res_size);
67 /* The input operand is smaller than 2**CNT. We perform a no-op,
68 apart from that we might need to copy IN to RES. */
70 if (res->_mp_alloc < res_size)
71 _mpz_realloc (res, res_size);
77 MPN_COPY (res->_mp_d, in->_mp_d, limb_cnt);
78 res->_mp_size = in->_mp_size >= 0 ? res_size : -res_size;