Annotation of OpenXM_contrib/gmp/mpz/tdiv_q_2exp.c, Revision 1.1.1.3
1.1 maekawa 1: /* mpz_tdiv_q_2exp -- Divide an integer by 2**CNT. Round the quotient
2: towards -infinity.
3:
1.1.1.3 ! ohara 4: Copyright 1991, 1993, 1994, 1996, 2001, 2002 Free Software Foundation, Inc.
1.1 maekawa 5:
6: This file is part of the GNU MP Library.
7:
8: The GNU MP Library is free software; you can redistribute it and/or modify
1.1.1.2 maekawa 9: it under the terms of the GNU Lesser General Public License as published by
10: the Free Software Foundation; either version 2.1 of the License, or (at your
1.1 maekawa 11: option) any later version.
12:
13: The GNU MP Library is distributed in the hope that it will be useful, but
14: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
1.1.1.2 maekawa 15: or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
1.1 maekawa 16: License for more details.
17:
1.1.1.2 maekawa 18: You should have received a copy of the GNU Lesser General Public License
1.1 maekawa 19: along with the GNU MP Library; see the file COPYING.LIB. If not, write to
20: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
21: MA 02111-1307, USA. */
22:
23: #include "gmp.h"
24: #include "gmp-impl.h"
25:
26: void
27: mpz_tdiv_q_2exp (mpz_ptr w, mpz_srcptr u, unsigned long int cnt)
28: {
29: mp_size_t usize, wsize;
30: mp_size_t limb_cnt;
31:
32: usize = u->_mp_size;
1.1.1.3 ! ohara 33: limb_cnt = cnt / GMP_NUMB_BITS;
1.1 maekawa 34: wsize = ABS (usize) - limb_cnt;
35: if (wsize <= 0)
36: w->_mp_size = 0;
37: else
38: {
39: mp_ptr wp;
40: mp_srcptr up;
41:
42: if (w->_mp_alloc < wsize)
43: _mpz_realloc (w, wsize);
44:
45: wp = w->_mp_d;
46: up = u->_mp_d;
47:
1.1.1.3 ! ohara 48: cnt %= GMP_NUMB_BITS;
1.1 maekawa 49: if (cnt != 0)
50: {
51: mpn_rshift (wp, up + limb_cnt, wsize, cnt);
52: wsize -= wp[wsize - 1] == 0;
53: }
54: else
55: {
56: MPN_COPY_INCR (wp, up + limb_cnt, wsize);
57: }
58:
59: w->_mp_size = usize >= 0 ? wsize : -wsize;
60: }
61: }
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>