92 lines
2.7 KiB
C
92 lines
2.7 KiB
C
|
/*=============================================================================
|
||
|
|
|
||
|
|
This file is part of FLINT.
|
||
|
|
|
||
|
|
FLINT is free software; you can redistribute it and/or modify
|
||
|
|
it under the terms of the GNU General Public License as published by
|
||
|
|
the Free Software Foundation; either version 2 of the License, or
|
||
|
|
(at your option) any later version.
|
||
|
|
|
||
|
|
FLINT 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 General Public License for more details.
|
||
|
|
|
||
|
|
You should have received a copy of the GNU General Public License
|
||
|
|
along with FLINT; if not, write to the Free Software
|
||
|
|
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
||
|
|
|
||
|
|
=============================================================================*/
|
||
|
|
/******************************************************************************
|
||
|
|
|
||
|
|
Copyright (C) 2011 William Hart
|
||
|
|
|
||
|
|
******************************************************************************/
|
||
|
|
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <gmp.h>
|
||
|
|
#include "flint.h"
|
||
|
|
#include "fmpz.h"
|
||
|
|
#include "mpn_extras.h"
|
||
|
|
|
||
|
|
mp_size_t flint_mpn_gcd_full(mp_ptr arrayg,
|
||
|
|
mp_ptr array1, mp_size_t limbs1, mp_ptr array2, mp_size_t limbs2)
|
||
|
|
{
|
||
|
|
mp_size_t s1 = 0, s2 = 0, m, b1, b2, mb, len1, len2, leng;
|
||
|
|
mp_ptr in1, in2;
|
||
|
|
mp_limb_t cy;
|
||
|
|
|
||
|
|
/* find maximum power of 2 dividing inputs */
|
||
|
|
b1 = mpn_scan1(array1 + s1, 0);
|
||
|
|
b2 = mpn_scan1(array2 + s2, 0);
|
||
|
|
|
||
|
|
/* get bit shifts [0, FLINT_BITS) and limb shifts */
|
||
|
|
mb = FLINT_MIN(b1, b2) % FLINT_BITS;
|
||
|
|
s1 = b1 / FLINT_BITS; b1 = b1 % FLINT_BITS; len1 = limbs1 - s1;
|
||
|
|
s2 = b2 / FLINT_BITS; b2 = b2 % FLINT_BITS; len2 = limbs2 - s2;
|
||
|
|
m = FLINT_MIN(s1, s2);
|
||
|
|
|
||
|
|
/* this many output limbs will be zero */
|
||
|
|
flint_mpn_zero(arrayg, m);
|
||
|
|
|
||
|
|
/* set in1 to shifted array1 */
|
||
|
|
if (b1 == 0)
|
||
|
|
in1 = array1 + s1;
|
||
|
|
else
|
||
|
|
{
|
||
|
|
in1 = flint_malloc(len1*sizeof(mp_limb_t));
|
||
|
|
mpn_rshift(in1, array1 + s1, len1, b1);
|
||
|
|
len1 -= (in1[len1 - 1] == 0);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* set in2 to shifted array2 */
|
||
|
|
if (b2 == 0)
|
||
|
|
in2 = array2 + s2;
|
||
|
|
else
|
||
|
|
{
|
||
|
|
in2 = flint_malloc(len2*sizeof(mp_limb_t));
|
||
|
|
mpn_rshift(in2, array2 + s2, len2, b2);
|
||
|
|
len2 -= (in2[len2 - 1] == 0);
|
||
|
|
}
|
||
|
|
|
||
|
|
/* compute gcd of shifted values */
|
||
|
|
if (len1 >= len2)
|
||
|
|
leng = mpn_gcd(arrayg + m, in1, len1, in2, len2);
|
||
|
|
else
|
||
|
|
leng = mpn_gcd(arrayg + m, in2, len2, in1, len1);
|
||
|
|
|
||
|
|
if (mb) /* shift back by mb bits */
|
||
|
|
{
|
||
|
|
cy = mpn_lshift(arrayg + m, arrayg + m, leng, mb);
|
||
|
|
if (cy)
|
||
|
|
arrayg[m + leng++] = cy;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* clean up */
|
||
|
|
if (b1) flint_free(in1);
|
||
|
|
if (b2) flint_free(in2);
|
||
|
|
|
||
|
|
/* return total number of limbs in output */
|
||
|
|
return m + leng;
|
||
|
|
}
|