1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
|
/* mpz_tdiv_q_2exp -- Divide an integer by 2**CNT. Round the quotient
towards -infinity.
Copyright 1991, 1993, 1994, 1996, 2001, 2002, 2012 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 https://www.gnu.org/licenses/. */
#include "gmp.h"
#include "gmp-impl.h"
void
mpz_tdiv_q_2exp (mpz_ptr r, mpz_srcptr u, mp_bitcnt_t cnt)
{
mp_size_t un, rn;
mp_size_t limb_cnt;
mp_ptr rp;
mp_srcptr up;
un = SIZ(u);
limb_cnt = cnt / GMP_NUMB_BITS;
rn = ABS (un) - limb_cnt;
if (rn <= 0)
rn = 0;
else
{
rp = MPZ_REALLOC (r, rn);
up = PTR(u) + limb_cnt;
cnt %= GMP_NUMB_BITS;
if (cnt != 0)
{
mpn_rshift (rp, up, rn, cnt);
rn -= rp[rn - 1] == 0;
}
else
{
MPN_COPY_INCR (rp, up, rn);
}
}
SIZ(r) = un >= 0 ? rn : -rn;
}
|
