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d02b48c6 | 1 | /* crypto/bn/bn_shift.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 | int BN_lshift1(BIGNUM *r, BIGNUM *a) |
d02b48c6 RE |
64 | { |
65 | register BN_ULONG *ap,*rp,t,c; | |
66 | int i; | |
67 | ||
68 | if (r != a) | |
69 | { | |
70 | r->neg=a->neg; | |
58964a49 | 71 | if (bn_wexpand(r,a->top+1) == NULL) return(0); |
d02b48c6 RE |
72 | r->top=a->top; |
73 | } | |
74 | else | |
75 | { | |
58964a49 | 76 | if (bn_wexpand(r,a->top+1) == NULL) return(0); |
d02b48c6 RE |
77 | } |
78 | ap=a->d; | |
79 | rp=r->d; | |
80 | c=0; | |
81 | for (i=0; i<a->top; i++) | |
82 | { | |
83 | t= *(ap++); | |
84 | *(rp++)=((t<<1)|c)&BN_MASK2; | |
85 | c=(t & BN_TBIT)?1:0; | |
86 | } | |
87 | if (c) | |
88 | { | |
89 | *rp=1; | |
90 | r->top++; | |
91 | } | |
92 | return(1); | |
93 | } | |
94 | ||
6b691a5c | 95 | int BN_rshift1(BIGNUM *r, BIGNUM *a) |
d02b48c6 RE |
96 | { |
97 | BN_ULONG *ap,*rp,t,c; | |
98 | int i; | |
99 | ||
100 | if (BN_is_zero(a)) | |
101 | { | |
102 | BN_zero(r); | |
103 | return(1); | |
104 | } | |
105 | if (a != r) | |
106 | { | |
58964a49 | 107 | if (bn_wexpand(r,a->top) == NULL) return(0); |
d02b48c6 RE |
108 | r->top=a->top; |
109 | r->neg=a->neg; | |
110 | } | |
111 | ap=a->d; | |
112 | rp=r->d; | |
113 | c=0; | |
114 | for (i=a->top-1; i>=0; i--) | |
115 | { | |
116 | t=ap[i]; | |
117 | rp[i]=((t>>1)&BN_MASK2)|c; | |
118 | c=(t&1)?BN_TBIT:0; | |
119 | } | |
120 | bn_fix_top(r); | |
121 | return(1); | |
122 | } | |
123 | ||
84c15db5 | 124 | int BN_lshift(BIGNUM *r, const BIGNUM *a, int n) |
d02b48c6 RE |
125 | { |
126 | int i,nw,lb,rb; | |
127 | BN_ULONG *t,*f; | |
128 | BN_ULONG l; | |
129 | ||
130 | r->neg=a->neg; | |
58964a49 | 131 | if (bn_wexpand(r,a->top+(n/BN_BITS2)+1) == NULL) return(0); |
d02b48c6 RE |
132 | nw=n/BN_BITS2; |
133 | lb=n%BN_BITS2; | |
134 | rb=BN_BITS2-lb; | |
135 | f=a->d; | |
136 | t=r->d; | |
137 | t[a->top+nw]=0; | |
138 | if (lb == 0) | |
139 | for (i=a->top-1; i>=0; i--) | |
140 | t[nw+i]=f[i]; | |
141 | else | |
142 | for (i=a->top-1; i>=0; i--) | |
143 | { | |
144 | l=f[i]; | |
145 | t[nw+i+1]|=(l>>rb)&BN_MASK2; | |
146 | t[nw+i]=(l<<lb)&BN_MASK2; | |
147 | } | |
148 | memset(t,0,nw*sizeof(t[0])); | |
149 | /* for (i=0; i<nw; i++) | |
150 | t[i]=0;*/ | |
151 | r->top=a->top+nw+1; | |
152 | bn_fix_top(r); | |
153 | return(1); | |
154 | } | |
155 | ||
6b691a5c | 156 | int BN_rshift(BIGNUM *r, BIGNUM *a, int n) |
d02b48c6 RE |
157 | { |
158 | int i,j,nw,lb,rb; | |
159 | BN_ULONG *t,*f; | |
160 | BN_ULONG l,tmp; | |
161 | ||
162 | nw=n/BN_BITS2; | |
163 | rb=n%BN_BITS2; | |
164 | lb=BN_BITS2-rb; | |
24bec03b | 165 | if (nw > a->top || a->top == 0) |
d02b48c6 RE |
166 | { |
167 | BN_zero(r); | |
168 | return(1); | |
169 | } | |
170 | if (r != a) | |
171 | { | |
172 | r->neg=a->neg; | |
58964a49 | 173 | if (bn_wexpand(r,a->top-nw+1) == NULL) return(0); |
d02b48c6 RE |
174 | } |
175 | ||
176 | f= &(a->d[nw]); | |
177 | t=r->d; | |
178 | j=a->top-nw; | |
179 | r->top=j; | |
180 | ||
181 | if (rb == 0) | |
182 | { | |
183 | for (i=j+1; i > 0; i--) | |
184 | *(t++)= *(f++); | |
185 | } | |
186 | else | |
187 | { | |
188 | l= *(f++); | |
189 | for (i=1; i<j; i++) | |
190 | { | |
191 | tmp =(l>>rb)&BN_MASK2; | |
192 | l= *(f++); | |
193 | *(t++) =(tmp|(l<<lb))&BN_MASK2; | |
194 | } | |
195 | *(t++) =(l>>rb)&BN_MASK2; | |
196 | } | |
197 | *t=0; | |
198 | bn_fix_top(r); | |
199 | return(1); | |
200 | } |