Mercurial > dropbear
comparison libtommath/bn_mp_lshd.c @ 1655:f52919ffd3b1
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
* make key-generation compliant to FIPS 186.4
* fix includes in tommath_class.h
* update fuzzcorpus instead of error-out
* fixup fuzzing make-targets
* update Makefile.in
* apply necessary patches to ltm sources
* clean-up not required ltm files
* update to vanilla ltm 1.1.0
this already only contains the required files
* remove set/get double
author | Steffen Jaeckel <s_jaeckel@gmx.de> |
---|---|
date | Mon, 16 Sep 2019 15:50:38 +0200 |
parents | 8bba51a55704 |
children | 1051e4eea25a |
comparison
equal
deleted
inserted
replaced
1654:cc0fc5131c5c | 1655:f52919ffd3b1 |
---|---|
1 #include <tommath_private.h> | 1 #include "tommath_private.h" |
2 #ifdef BN_MP_LSHD_C | 2 #ifdef BN_MP_LSHD_C |
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis | 3 /* LibTomMath, multiple-precision integer library -- Tom St Denis |
4 * | 4 * |
5 * LibTomMath is a library that provides multiple-precision | 5 * LibTomMath is a library that provides multiple-precision |
6 * integer arithmetic as well as number theoretic functionality. | 6 * integer arithmetic as well as number theoretic functionality. |
7 * | 7 * |
8 * The library was designed directly after the MPI library by | 8 * The library was designed directly after the MPI library by |
9 * Michael Fromberger but has been written from scratch with | 9 * Michael Fromberger but has been written from scratch with |
10 * additional optimizations in place. | 10 * additional optimizations in place. |
11 * | 11 * |
12 * The library is free for all purposes without any express | 12 * SPDX-License-Identifier: Unlicense |
13 * guarantee it works. | |
14 * | |
15 * Tom St Denis, [email protected], http://libtom.org | |
16 */ | 13 */ |
17 | 14 |
18 /* shift left a certain amount of digits */ | 15 /* shift left a certain amount of digits */ |
19 int mp_lshd (mp_int * a, int b) | 16 int mp_lshd(mp_int *a, int b) |
20 { | 17 { |
21 int x, res; | 18 int x, res; |
22 | 19 |
23 /* if its less than zero return */ | 20 /* if its less than zero return */ |
24 if (b <= 0) { | 21 if (b <= 0) { |
25 return MP_OKAY; | 22 return MP_OKAY; |
26 } | 23 } |
24 /* no need to shift 0 around */ | |
25 if (mp_iszero(a) == MP_YES) { | |
26 return MP_OKAY; | |
27 } | |
27 | 28 |
28 /* grow to fit the new digits */ | 29 /* grow to fit the new digits */ |
29 if (a->alloc < (a->used + b)) { | 30 if (a->alloc < (a->used + b)) { |
30 if ((res = mp_grow (a, a->used + b)) != MP_OKAY) { | 31 if ((res = mp_grow(a, a->used + b)) != MP_OKAY) { |
31 return res; | 32 return res; |
32 } | 33 } |
33 } | 34 } |
34 | 35 |
35 { | 36 { |
36 mp_digit *top, *bottom; | 37 mp_digit *top, *bottom; |
37 | 38 |
38 /* increment the used by the shift amount then copy upwards */ | 39 /* increment the used by the shift amount then copy upwards */ |
39 a->used += b; | 40 a->used += b; |
40 | 41 |
41 /* top */ | 42 /* top */ |
42 top = a->dp + a->used - 1; | 43 top = a->dp + a->used - 1; |
43 | 44 |
44 /* base */ | 45 /* base */ |
45 bottom = (a->dp + a->used - 1) - b; | 46 bottom = (a->dp + a->used - 1) - b; |
46 | 47 |
47 /* much like mp_rshd this is implemented using a sliding window | 48 /* much like mp_rshd this is implemented using a sliding window |
48 * except the window goes the otherway around. Copying from | 49 * except the window goes the otherway around. Copying from |
49 * the bottom to the top. see bn_mp_rshd.c for more info. | 50 * the bottom to the top. see bn_mp_rshd.c for more info. |
50 */ | 51 */ |
51 for (x = a->used - 1; x >= b; x--) { | 52 for (x = a->used - 1; x >= b; x--) { |
52 *top-- = *bottom--; | 53 *top-- = *bottom--; |
53 } | 54 } |
54 | 55 |
55 /* zero the lower digits */ | 56 /* zero the lower digits */ |
56 top = a->dp; | 57 top = a->dp; |
57 for (x = 0; x < b; x++) { | 58 for (x = 0; x < b; x++) { |
58 *top++ = 0; | 59 *top++ = 0; |
59 } | 60 } |
60 } | 61 } |
61 return MP_OKAY; | 62 return MP_OKAY; |
62 } | 63 } |
63 #endif | 64 #endif |
64 | 65 |
65 /* ref: $Format:%D$ */ | 66 /* ref: HEAD -> master, tag: v1.1.0 */ |
66 /* git commit: $Format:%H$ */ | 67 /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */ |
67 /* commit time: $Format:%ai$ */ | 68 /* commit time: 2019-01-28 20:32:32 +0100 */ |