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/* This file is part of the gf2x library.
Copyright 2007, 2008, 2009, 2010
Richard Brent, Pierrick Gaudry, Emmanuel Thome', Paul Zimmermann
This program 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.
This program 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 this program; see the file COPYING. If not, write to the Free
Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
02111-1307, USA.
*/
#ifndef GF2X_MUL3_H_
#define GF2X_MUL3_H_
#include "gf2x.h"
/* All gf2x source files for lowlevel functions must include gf2x-small.h
* This is mandatory for the tuning mechanism. */
#include "gf2x/gf2x-small.h"
#include <wmmintrin.h>
#if GF2X_WORDSIZE != 64
#error "This code is for 64-bit only"
#endif
#include "gf2x/gf2x-config.h"
#ifndef HAVE_PCLMUL_SUPPORT
#error "This code needs pclmul support"
#endif
/* XXX XXX XXX This is dangerous XXX XXX XXX
*
* we are here exposing gf2x_mul2b and gf2x_mul2c, with unprotected
* prefixes. If another source file happens to also define this functions
* with the same mechanism, both cannot coexist.
*/
#undef GF2X_MUL2_H_
#define CARRY
#include "mul2cl.c"
#undef CARRY
#undef GF2X_MUL2_H_
#define BORROW
#include "mul2cl.c"
#undef BORROW
/* uses Montgomery's variant of Karatsuba for n=2k+1 odd,
with M(2k+1) = M(k) + 2M(k+1) - 1, see
Five, Six, and Seven-Term {K}aratsuba-Like Formulae,
IEEE Transactions on Computers, volume 54, number 3, pages 362-369, 2005 */
GF2X_STORAGE_CLASS_mul3 void
gf2x_mul3 (unsigned long *c, const unsigned long *a, const unsigned long *b)
{
unsigned long d[2], aa[2], bb[2], p[4];
/* let A0 = {a, 2}, A1 = {a+2, 1}, B0 = {b, 2}, B1 = {b+2, 1} */
aa[0] = a[0] ^ a[2];
aa[1] = a[1];
bb[0] = b[0] ^ b[2];
bb[1] = b[1];
gf2x_mul2c (c, a, b, d);
/* {c, 4} = A0 * B0 and {d, 2} = {a+1, 1} * {b+1, 1} */
gf2x_mul2b (p, aa, bb, d);
/* {p, 4} = (A0 + A1) * (B0 + B1) */
gf2x_mul1 (c + 4, a[2], b[2]);
p[0] ^= c[0] ^ c[4];
p[1] ^= c[1] ^ c[5];
c[5] ^= p[3] ^ c[3];
c[4] ^= p[2] ^ c[2];
c[2] ^= p[0];
c[3] ^= p[1];
}
#endif /* GF2X_MUL3_H_ */
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