diff options
author | James Morris <jmorris@namei.org> | 2012-01-08 20:16:48 -0500 |
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committer | James Morris <jmorris@namei.org> | 2012-01-08 20:16:48 -0500 |
commit | 8fcc99549522fc7a0bbaeb5755855ab0d9a59ce8 (patch) | |
tree | a118eaef15d4ba22247f45ee01537ecc906cd161 /lib/mpi/generic_mpih-sub1.c | |
parent | 805a6af8dba5dfdd35ec35dc52ec0122400b2610 (diff) | |
parent | 7b7e5916aa2f46e57f8bd8cb89c34620ebfda5da (diff) |
Merge branch 'next' into for-linus
Conflicts:
security/integrity/evm/evm_crypto.c
Resolved upstream fix vs. next conflict manually.
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'lib/mpi/generic_mpih-sub1.c')
-rw-r--r-- | lib/mpi/generic_mpih-sub1.c | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/lib/mpi/generic_mpih-sub1.c b/lib/mpi/generic_mpih-sub1.c new file mode 100644 index 000000000000..5d98ab7d6853 --- /dev/null +++ b/lib/mpi/generic_mpih-sub1.c | |||
@@ -0,0 +1,60 @@ | |||
1 | /* mpihelp-add_2.c - MPI helper functions | ||
2 | * Copyright (C) 1994, 1996, 1997, 1998, 2001 Free Software Foundation, Inc. | ||
3 | * | ||
4 | * This file is part of GnuPG. | ||
5 | * | ||
6 | * GnuPG is free software; you can redistribute it and/or modify | ||
7 | * it under the terms of the GNU General Public License as published by | ||
8 | * the Free Software Foundation; either version 2 of the License, or | ||
9 | * (at your option) any later version. | ||
10 | * | ||
11 | * GnuPG is distributed in the hope that it will be useful, | ||
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
14 | * GNU General Public License for more details. | ||
15 | * | ||
16 | * You should have received a copy of the GNU General Public License | ||
17 | * along with this program; if not, write to the Free Software | ||
18 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA | ||
19 | * | ||
20 | * Note: This code is heavily based on the GNU MP Library. | ||
21 | * Actually it's the same code with only minor changes in the | ||
22 | * way the data is stored; this is to support the abstraction | ||
23 | * of an optional secure memory allocation which may be used | ||
24 | * to avoid revealing of sensitive data due to paging etc. | ||
25 | * The GNU MP Library itself is published under the LGPL; | ||
26 | * however I decided to publish this code under the plain GPL. | ||
27 | */ | ||
28 | |||
29 | #include "mpi-internal.h" | ||
30 | #include "longlong.h" | ||
31 | |||
32 | mpi_limb_t | ||
33 | mpihelp_sub_n(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, | ||
34 | mpi_ptr_t s2_ptr, mpi_size_t size) | ||
35 | { | ||
36 | mpi_limb_t x, y, cy; | ||
37 | mpi_size_t j; | ||
38 | |||
39 | /* The loop counter and index J goes from -SIZE to -1. This way | ||
40 | the loop becomes faster. */ | ||
41 | j = -size; | ||
42 | |||
43 | /* Offset the base pointers to compensate for the negative indices. */ | ||
44 | s1_ptr -= j; | ||
45 | s2_ptr -= j; | ||
46 | res_ptr -= j; | ||
47 | |||
48 | cy = 0; | ||
49 | do { | ||
50 | y = s2_ptr[j]; | ||
51 | x = s1_ptr[j]; | ||
52 | y += cy; /* add previous carry to subtrahend */ | ||
53 | cy = y < cy; /* get out carry from that addition */ | ||
54 | y = x - y; /* main subtract */ | ||
55 | cy += y > x; /* get out carry from the subtract, combine */ | ||
56 | res_ptr[j] = y; | ||
57 | } while (++j); | ||
58 | |||
59 | return cy; | ||
60 | } | ||