121 lines
2.9 KiB
C
121 lines
2.9 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) 2013 William Hart
|
|
|
|
******************************************************************************/
|
|
|
|
#include <stdlib.h>
|
|
#include <gmp.h>
|
|
#include "flint.h"
|
|
#include "longlong.h"
|
|
#include "mpn_extras.h"
|
|
|
|
/*
|
|
TODO: speedup mpir's mullow and mulhigh and use instead of mul/mul_n
|
|
*/
|
|
|
|
mp_limb_t flint_mpn_divrem_preinvn(mp_ptr qp, mp_ptr rp, mp_srcptr ap, mp_size_t m,
|
|
mp_srcptr d, mp_size_t n, mp_srcptr dinv)
|
|
{
|
|
mp_limb_t cy, hi = 0;
|
|
mp_ptr t, q, r, a;
|
|
mp_size_t size;
|
|
TMP_INIT;
|
|
|
|
a = (mp_ptr) ap + m - 2*n;
|
|
r = rp + m - 2*n;
|
|
|
|
/* check if top n limbs of a exceed d */
|
|
if (mpn_cmp(a + n, d, n) >= 0)
|
|
{
|
|
mpn_sub_n(r + n, a + n, d, n);
|
|
hi = 1;
|
|
} else if (r != a)
|
|
mpn_copyi(r + n, a + n, n);
|
|
|
|
q = qp + m - 2*n;
|
|
|
|
TMP_START;
|
|
t = TMP_ALLOC(2*n*sizeof(mp_limb_t));
|
|
|
|
/* 2n by n division */
|
|
while (m >= 2*n)
|
|
{
|
|
mpn_mul_n(t, dinv, r + n, n);
|
|
cy = mpn_add_n(q, t + n, r + n, n);
|
|
|
|
mpn_mul_n(t, d, q, n);
|
|
cy = r[n] - t[n] - mpn_sub_n(r, a, t, n);
|
|
|
|
while (cy > 0)
|
|
{
|
|
cy -= mpn_sub_n(r, r, d, n);
|
|
mpn_add_1(q, q, n, 1);
|
|
}
|
|
|
|
if (mpn_cmp(r, d, n) >= 0)
|
|
{
|
|
mpn_sub_n(r, r, d, n);
|
|
mpn_add_1(q, q, n, 1);
|
|
}
|
|
|
|
m -= n;
|
|
r -= n;
|
|
a -= n;
|
|
q -= n;
|
|
}
|
|
|
|
size = m - n;
|
|
|
|
/* m by n division with 2n > m > n */
|
|
if (size)
|
|
{
|
|
if (rp != ap)
|
|
mpn_copyi(rp, ap, size);
|
|
|
|
mpn_mul(t, dinv, n, rp + n, size);
|
|
cy = mpn_add_n(qp, t + n, rp + n, size);
|
|
|
|
mpn_mul(t, d, n, qp, size);
|
|
if (cy)
|
|
mpn_add_n(t + size, t + size, d, n + 1 - size);
|
|
|
|
cy = rp[n] - t[n] - mpn_sub_n(rp, rp, t, n);
|
|
|
|
while (cy > 0)
|
|
{
|
|
cy -= mpn_sub_n(rp, rp, d, n);
|
|
mpn_add_1(qp, qp, size, 1);
|
|
}
|
|
|
|
if (mpn_cmp(rp, d, n) >= 0)
|
|
{
|
|
mpn_sub_n(rp, rp, d, n);
|
|
mpn_add_1(qp, qp, size, 1);
|
|
}
|
|
}
|
|
|
|
TMP_END;
|
|
|
|
return hi;
|
|
}
|