source: grub-pc/trunk/fuentes/grub-core/lib/libgcrypt-grub/mpi/mpih-add1.c @ 22

Last change on this file since 22 was 22, checked in by mabarracus, 5 years ago

updated version and apply net.ifnames=0 into debian/rules

File size: 2.0 KB
Line 
1/* mpihelp-add_1.c  -  MPI helper functions
2 * Copyright (C) 1994, 1996, 1997, 1998,
3 *               2000, 2002 Free Software Foundation, Inc.
4 *
5 * This file is part of Libgcrypt.
6 *
7 * Libgcrypt is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU Lesser General Public License as
9 * published by the Free Software Foundation; either version 2.1 of
10 * the License, or (at your option) any later version.
11 *
12 * Libgcrypt is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
20 *
21 * Note: This code is heavily based on the GNU MP Library.
22 *       Actually it's the same code with only minor changes in the
23 *       way the data is stored; this is to support the abstraction
24 *       of an optional secure memory allocation which may be used
25 *       to avoid revealing of sensitive data due to paging etc.
26 */
27
28#include <config.h>
29#include <stdio.h>
30#include <stdlib.h>
31#include "mpi-internal.h"
32#include "longlong.h"
33
34mpi_limb_t
35_gcry_mpih_add_n (mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
36                  mpi_ptr_t s2_ptr, mpi_size_t size)
37{
38  mpi_limb_t x, y, cy;
39  mpi_size_t j;
40
41  /* The loop counter and index J goes from -SIZE to -1.  This way
42     the loop becomes faster.  */
43  j = -size;
44
45  /* Offset the base pointers to compensate for the negative indices. */
46  s1_ptr -= j;
47  s2_ptr -= j;
48  res_ptr -= j;
49
50  cy = 0;
51  do 
52    {
53      y = s2_ptr[j];
54      x = s1_ptr[j];
55      y += cy;            /* add previous carry to one addend */
56      cy = y < cy;        /* get out carry from that addition */
57      y += x;             /* add other addend */
58      cy += y < x;        /* get out carry from that add, combine */
59      res_ptr[j] = y;
60    } 
61  while ( ++j );
62
63  return cy;
64}
65
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