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d02b48c6 | 1 | /* crypto/bn/bn_word.c */ |
58964a49 | 2 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
d02b48c6 RE |
3 | * All rights reserved. |
4 | * | |
5 | * This package is an SSL implementation written | |
6 | * by Eric Young (eay@cryptsoft.com). | |
7 | * The implementation was written so as to conform with Netscapes SSL. | |
8 | * | |
9 | * This library is free for commercial and non-commercial use as long as | |
10 | * the following conditions are aheared to. The following conditions | |
11 | * apply to all code found in this distribution, be it the RC4, RSA, | |
12 | * lhash, DES, etc., code; not just the SSL code. The SSL documentation | |
13 | * included with this distribution is covered by the same copyright terms | |
14 | * except that the holder is Tim Hudson (tjh@cryptsoft.com). | |
15 | * | |
16 | * Copyright remains Eric Young's, and as such any Copyright notices in | |
17 | * the code are not to be removed. | |
18 | * If this package is used in a product, Eric Young should be given attribution | |
19 | * as the author of the parts of the library used. | |
20 | * This can be in the form of a textual message at program startup or | |
21 | * in documentation (online or textual) provided with the package. | |
22 | * | |
23 | * Redistribution and use in source and binary forms, with or without | |
24 | * modification, are permitted provided that the following conditions | |
25 | * are met: | |
26 | * 1. Redistributions of source code must retain the copyright | |
27 | * notice, this list of conditions and the following disclaimer. | |
28 | * 2. Redistributions in binary form must reproduce the above copyright | |
29 | * notice, this list of conditions and the following disclaimer in the | |
30 | * documentation and/or other materials provided with the distribution. | |
31 | * 3. All advertising materials mentioning features or use of this software | |
32 | * must display the following acknowledgement: | |
33 | * "This product includes cryptographic software written by | |
34 | * Eric Young (eay@cryptsoft.com)" | |
35 | * The word 'cryptographic' can be left out if the rouines from the library | |
36 | * being used are not cryptographic related :-). | |
37 | * 4. If you include any Windows specific code (or a derivative thereof) from | |
38 | * the apps directory (application code) you must include an acknowledgement: | |
39 | * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" | |
40 | * | |
41 | * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND | |
42 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
43 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
44 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |
45 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
46 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
47 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
48 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
49 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
50 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
51 | * SUCH DAMAGE. | |
52 | * | |
53 | * The licence and distribution terms for any publically available version or | |
54 | * derivative of this code cannot be changed. i.e. this code cannot simply be | |
55 | * copied and put under another distribution licence | |
56 | * [including the GNU Public Licence.] | |
57 | */ | |
58 | ||
59 | #include <stdio.h> | |
60 | #include "cryptlib.h" | |
61 | #include "bn_lcl.h" | |
62 | ||
6b691a5c | 63 | BN_ULONG BN_mod_word(BIGNUM *a, BN_ULONG w) |
d02b48c6 RE |
64 | { |
65 | #ifndef BN_LLONG | |
66 | BN_ULONG ret=0; | |
67 | #else | |
68 | BN_ULLONG ret=0; | |
69 | #endif | |
70 | int i; | |
71 | ||
58964a49 | 72 | w&=BN_MASK2; |
d02b48c6 RE |
73 | for (i=a->top-1; i>=0; i--) |
74 | { | |
75 | #ifndef BN_LLONG | |
dfeab068 RE |
76 | ret=((ret<<BN_BITS4)|((a->d[i]>>BN_BITS4)&BN_MASK2l))%w; |
77 | ret=((ret<<BN_BITS4)|(a->d[i]&BN_MASK2l))%w; | |
d02b48c6 RE |
78 | #else |
79 | ret=(BN_ULLONG)(((ret<<(BN_ULLONG)BN_BITS2)|a->d[i])% | |
80 | (BN_ULLONG)w); | |
81 | #endif | |
82 | } | |
83 | return((BN_ULONG)ret); | |
84 | } | |
85 | ||
6b691a5c | 86 | BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w) |
d02b48c6 RE |
87 | { |
88 | BN_ULONG ret; | |
89 | int i; | |
90 | ||
91 | if (a->top == 0) return(0); | |
92 | ret=0; | |
58964a49 | 93 | w&=BN_MASK2; |
d02b48c6 RE |
94 | for (i=a->top-1; i>=0; i--) |
95 | { | |
58964a49 RE |
96 | BN_ULONG l,d; |
97 | ||
98 | l=a->d[i]; | |
dfeab068 | 99 | d=bn_div_words(ret,l,w); |
58964a49 RE |
100 | ret=(l-((d*w)&BN_MASK2))&BN_MASK2; |
101 | a->d[i]=d; | |
d02b48c6 | 102 | } |
dfeab068 | 103 | if ((a->top > 0) && (a->d[a->top-1] == 0)) |
d02b48c6 RE |
104 | a->top--; |
105 | return(ret); | |
106 | } | |
107 | ||
6b691a5c | 108 | int BN_add_word(BIGNUM *a, BN_ULONG w) |
d02b48c6 RE |
109 | { |
110 | BN_ULONG l; | |
111 | int i; | |
112 | ||
58964a49 RE |
113 | if (a->neg) |
114 | { | |
115 | a->neg=0; | |
116 | i=BN_sub_word(a,w); | |
117 | if (!BN_is_zero(a)) | |
118 | a->neg=1; | |
119 | return(i); | |
120 | } | |
121 | w&=BN_MASK2; | |
122 | if (bn_wexpand(a,a->top+1) == NULL) return(0); | |
d02b48c6 RE |
123 | i=0; |
124 | for (;;) | |
125 | { | |
126 | l=(a->d[i]+(BN_ULONG)w)&BN_MASK2; | |
127 | a->d[i]=l; | |
128 | if (w > l) | |
129 | w=1; | |
130 | else | |
131 | break; | |
132 | i++; | |
133 | } | |
134 | if (i >= a->top) | |
135 | a->top++; | |
136 | return(1); | |
137 | } | |
138 | ||
6b691a5c | 139 | int BN_sub_word(BIGNUM *a, BN_ULONG w) |
d02b48c6 | 140 | { |
58964a49 | 141 | int i; |
d02b48c6 | 142 | |
58964a49 RE |
143 | if (a->neg) |
144 | { | |
145 | a->neg=0; | |
146 | i=BN_add_word(a,w); | |
147 | a->neg=1; | |
148 | return(i); | |
149 | } | |
d02b48c6 | 150 | |
58964a49 RE |
151 | w&=BN_MASK2; |
152 | if ((a->top == 1) && (a->d[0] < w)) | |
153 | { | |
154 | a->d[0]=w-a->d[0]; | |
155 | a->neg=1; | |
156 | return(1); | |
157 | } | |
158 | i=0; | |
159 | for (;;) | |
d02b48c6 | 160 | { |
58964a49 RE |
161 | if (a->d[i] >= w) |
162 | { | |
163 | a->d[i]-=w; | |
164 | break; | |
165 | } | |
166 | else | |
167 | { | |
168 | a->d[i]=(a->d[i]-w)&BN_MASK2; | |
169 | i++; | |
170 | w=1; | |
171 | } | |
172 | } | |
173 | if ((a->d[i] == 0) && (i == (a->top-1))) | |
174 | a->top--; | |
175 | return(1); | |
176 | } | |
d02b48c6 | 177 | |
6b691a5c | 178 | int BN_mul_word(BIGNUM *a, BN_ULONG w) |
58964a49 RE |
179 | { |
180 | BN_ULONG ll; | |
181 | ||
182 | w&=BN_MASK2; | |
183 | if (a->top) | |
184 | { | |
185 | ll=bn_mul_words(a->d,a->d,a->top,w); | |
186 | if (ll) | |
187 | { | |
188 | if (bn_wexpand(a,a->top+1) == NULL) return(0); | |
189 | a->d[a->top++]=ll; | |
190 | } | |
191 | } | |
dfeab068 | 192 | return(1); |
58964a49 | 193 | } |
d02b48c6 | 194 |