1 /* mpz_div_2exp -- Divide a bignum by 2**CNT
3 Copyright (C) 1991 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 General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 The GNU MP Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with the GNU MP Library; see the file COPYING. If not, write to
19 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
26 mpz_div_2exp (MP_INT *w, const MP_INT *u, unsigned long int cnt)
28 mpz_div_2exp (w, u, cnt)
31 unsigned long int cnt;
34 mp_size usize = u->size;
36 mp_size abs_usize = ABS (usize);
39 limb_cnt = cnt / BITS_PER_MP_LIMB;
40 wsize = abs_usize - limb_cnt;
46 _mpz_realloc (w, wsize);
48 wsize = mpn_rshift (w->d, u->d + limb_cnt, abs_usize - limb_cnt,
49 cnt % BITS_PER_MP_LIMB);
52 w->size = (usize >= 0) ? wsize : -wsize;