|
Packit |
5c3484 |
/* mpn_sub_err1_n -- sub_n with one error term
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
Contributed by David Harvey.
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
THE FUNCTION IN THIS FILE IS INTERNAL WITH A MUTABLE INTERFACE. IT IS ONLY
|
|
Packit |
5c3484 |
SAFE TO REACH IT THROUGH DOCUMENTED INTERFACES. IN FACT, IT IS ALMOST
|
|
Packit |
5c3484 |
GUARANTEED THAT IT'LL CHANGE OR DISAPPEAR IN A FUTURE GNU MP RELEASE.
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
Copyright 2011 Free Software Foundation, Inc.
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
This file is part of the GNU MP Library.
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
The GNU MP Library is free software; you can redistribute it and/or modify
|
|
Packit |
5c3484 |
it under the terms of either:
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
* the GNU Lesser General Public License as published by the Free
|
|
Packit |
5c3484 |
Software Foundation; either version 3 of the License, or (at your
|
|
Packit |
5c3484 |
option) any later version.
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
or
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
* the GNU General Public License as published by the Free Software
|
|
Packit |
5c3484 |
Foundation; either version 2 of the License, or (at your option) any
|
|
Packit |
5c3484 |
later version.
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
or both in parallel, as here.
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
The GNU MP Library is distributed in the hope that it will be useful, but
|
|
Packit |
5c3484 |
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|
|
Packit |
5c3484 |
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
Packit |
5c3484 |
for more details.
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
You should have received copies of the GNU General Public License and the
|
|
Packit |
5c3484 |
GNU Lesser General Public License along with the GNU MP Library. If not,
|
|
Packit |
5c3484 |
see https://www.gnu.org/licenses/. */
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
#include "gmp.h"
|
|
Packit |
5c3484 |
#include "gmp-impl.h"
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
/*
|
|
Packit |
5c3484 |
Computes:
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
(1) {rp,n} := {up,n} - {vp,n} (just like mpn_sub_n) with incoming borrow cy,
|
|
Packit |
5c3484 |
return value is borrow out.
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
(2) Let c[i+1] = borrow from i-th limb subtraction (c[0] = cy).
|
|
Packit |
5c3484 |
Computes c[1]*yp[n-1] + ... + c[n]*yp[0], stores two-limb result at ep.
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
Requires n >= 1.
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
None of the outputs may overlap each other or any of the inputs, except
|
|
Packit |
5c3484 |
that {rp,n} may be equal to {up,n} or {vp,n}.
|
|
Packit |
5c3484 |
*/
|
|
Packit |
5c3484 |
mp_limb_t
|
|
Packit |
5c3484 |
mpn_sub_err1_n (mp_ptr rp, mp_srcptr up, mp_srcptr vp,
|
|
Packit |
5c3484 |
mp_ptr ep, mp_srcptr yp,
|
|
Packit |
5c3484 |
mp_size_t n, mp_limb_t cy)
|
|
Packit |
5c3484 |
{
|
|
Packit |
5c3484 |
mp_limb_t el, eh, ul, vl, yl, zl, rl, sl, cy1, cy2;
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
ASSERT (n >= 1);
|
|
Packit |
5c3484 |
ASSERT (MPN_SAME_OR_SEPARATE_P (rp, up, n));
|
|
Packit |
5c3484 |
ASSERT (MPN_SAME_OR_SEPARATE_P (rp, vp, n));
|
|
Packit |
5c3484 |
ASSERT (! MPN_OVERLAP_P (rp, n, yp, n));
|
|
Packit |
5c3484 |
ASSERT (! MPN_OVERLAP_P (ep, 2, up, n));
|
|
Packit |
5c3484 |
ASSERT (! MPN_OVERLAP_P (ep, 2, vp, n));
|
|
Packit |
5c3484 |
ASSERT (! MPN_OVERLAP_P (ep, 2, yp, n));
|
|
Packit |
5c3484 |
ASSERT (! MPN_OVERLAP_P (ep, 2, rp, n));
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
yp += n - 1;
|
|
Packit |
5c3484 |
el = eh = 0;
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
do
|
|
Packit |
5c3484 |
{
|
|
Packit |
5c3484 |
yl = *yp--;
|
|
Packit |
5c3484 |
ul = *up++;
|
|
Packit |
5c3484 |
vl = *vp++;
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
/* ordinary sub_n */
|
|
Packit |
5c3484 |
SUBC_LIMB (cy1, sl, ul, vl);
|
|
Packit |
5c3484 |
SUBC_LIMB (cy2, rl, sl, cy);
|
|
Packit |
5c3484 |
cy = cy1 | cy2;
|
|
Packit |
5c3484 |
*rp++ = rl;
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
/* update (eh:el) */
|
|
Packit |
5c3484 |
zl = (-cy) & yl;
|
|
Packit |
5c3484 |
el += zl;
|
|
Packit |
5c3484 |
eh += el < zl;
|
|
Packit |
5c3484 |
}
|
|
Packit |
5c3484 |
while (--n);
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
#if GMP_NAIL_BITS != 0
|
|
Packit |
5c3484 |
eh = (eh << GMP_NAIL_BITS) + (el >> GMP_NUMB_BITS);
|
|
Packit |
5c3484 |
el &= GMP_NUMB_MASK;
|
|
Packit |
5c3484 |
#endif
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
ep[0] = el;
|
|
Packit |
5c3484 |
ep[1] = eh;
|
|
Packit |
5c3484 |
|
|
Packit |
5c3484 |
return cy;
|
|
Packit |
5c3484 |
}
|