56 lines
2.0 KiB
C
56 lines
2.0 KiB
C
|
/*
|
||
|
|
|
||
|
|
Copyright 2009, 2011 William Hart. All rights reserved.
|
||
|
|
|
||
|
|
Redistribution and use in source and binary forms, with or without modification, are
|
||
|
|
permitted provided that the following conditions are met:
|
||
|
|
|
||
|
|
1. Redistributions of source code must retain the above copyright notice, this list of
|
||
|
|
conditions and the following disclaimer.
|
||
|
|
|
||
|
|
2. Redistributions in binary form must reproduce the above copyright notice, this list
|
||
|
|
of conditions and the following disclaimer in the documentation and/or other materials
|
||
|
|
provided with the distribution.
|
||
|
|
|
||
|
|
THIS SOFTWARE IS PROVIDED BY William Hart ``AS IS'' AND ANY EXPRESS OR IMPLIED
|
||
|
|
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
|
||
|
|
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL William Hart OR
|
||
|
|
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
||
|
|
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
|
||
|
|
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
|
||
|
|
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
|
||
|
|
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
|
||
|
|
ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||
|
|
|
||
|
|
The views and conclusions contained in the software and documentation are those of the
|
||
|
|
authors and should not be interpreted as representing official policies, either expressed
|
||
|
|
or implied, of William Hart.
|
||
|
|
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "mpir.h"
|
||
|
|
#include "gmp-impl.h"
|
||
|
|
#include "longlong.h"
|
||
|
|
|
||
|
|
/* WARNING: relies on GCC's handling of >> as arithmetic shift right */
|
||
|
|
|
||
|
|
void mpn_div_2expmod_2expp1(mp_limb_t * t, mp_limb_t * i1, mp_size_t limbs, mp_bitcnt_t d)
|
||
|
|
{
|
||
|
|
mp_limb_t lo;
|
||
|
|
mp_limb_t * ptr;
|
||
|
|
mp_limb_signed_t hi;
|
||
|
|
|
||
|
|
if (d == 0)
|
||
|
|
{
|
||
|
|
if (t != i1)
|
||
|
|
mpn_copyi(t, i1, limbs + 1);
|
||
|
|
} else
|
||
|
|
{
|
||
|
|
hi = i1[limbs];
|
||
|
|
lo = mpn_rshift(t, i1, limbs + 1, d);
|
||
|
|
t[limbs] = (hi >> d);
|
||
|
|
ptr = t + limbs - 1;
|
||
|
|
sub_ddmmss(ptr[1], ptr[0], ptr[1], ptr[0], (mp_limb_t) 0, lo);
|
||
|
|
}
|
||
|
|
}
|