1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
4 * This package is an SSL implementation written
5 * by Eric Young (eay@cryptsoft.com).
6 * The implementation was written so as to conform with Netscapes SSL.
8 * This library is free for commercial and non-commercial use as long as
9 * the following conditions are aheared to. The following conditions
10 * apply to all code found in this distribution, be it the RC4, RSA,
11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
12 * included with this distribution is covered by the same copyright terms
13 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 * Copyright remains Eric Young's, and as such any Copyright notices in
16 * the code are not to be removed.
17 * If this package is used in a product, Eric Young should be given attribution
18 * as the author of the parts of the library used.
19 * This can be in the form of a textual message at program startup or
20 * in documentation (online or textual) provided with the package.
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
25 * 1. Redistributions of source code must retain the copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 * 3. All advertising materials mentioning features or use of this software
31 * must display the following acknowledgement:
32 * "This product includes cryptographic software written by
33 * Eric Young (eay@cryptsoft.com)"
34 * The word 'cryptographic' can be left out if the rouines from the library
35 * being used are not cryptographic related :-).
36 * 4. If you include any Windows specific code (or a derivative thereof) from
37 * the apps directory (application code) you must include an acknowledgement:
38 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
52 * The licence and distribution terms for any publically available version or
53 * derivative of this code cannot be changed. i.e. this code cannot simply be
54 * copied and put under another distribution licence
55 * [including the GNU Public Licence.]
58 #include "internal/cryptlib.h"
61 BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w)
75 for (i = a->top - 1; i >= 0; i--) {
77 ret = ((ret << BN_BITS4) | ((a->d[i] >> BN_BITS4) & BN_MASK2l)) % w;
78 ret = ((ret << BN_BITS4) | (a->d[i] & BN_MASK2l)) % w;
80 ret = (BN_ULLONG) (((ret << (BN_ULLONG) BN_BITS2) | a->d[i]) %
84 return ((BN_ULONG)ret);
87 BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w)
96 /* actually this an error (division by zero) */
101 /* normalize input (so bn_div_words doesn't complain) */
102 j = BN_BITS2 - BN_num_bits_word(w);
104 if (!BN_lshift(a, a, j))
107 for (i = a->top - 1; i >= 0; i--) {
111 d = bn_div_words(ret, l, w);
112 ret = (l - ((d * w) & BN_MASK2)) & BN_MASK2;
115 if ((a->top > 0) && (a->d[a->top - 1] == 0))
122 int BN_add_word(BIGNUM *a, BN_ULONG w)
130 /* degenerate case: w is zero */
133 /* degenerate case: a is zero */
135 return BN_set_word(a, w);
136 /* handle 'a' when negative */
139 i = BN_sub_word(a, w);
144 for (i = 0; w != 0 && i < a->top; i++) {
145 a->d[i] = l = (a->d[i] + w) & BN_MASK2;
148 if (w && i == a->top) {
149 if (bn_wexpand(a, a->top + 1) == NULL)
158 int BN_sub_word(BIGNUM *a, BN_ULONG w)
165 /* degenerate case: w is zero */
168 /* degenerate case: a is zero */
170 i = BN_set_word(a, w);
172 BN_set_negative(a, 1);
175 /* handle 'a' when negative */
178 i = BN_add_word(a, w);
183 if ((a->top == 1) && (a->d[0] < w)) {
184 a->d[0] = w - a->d[0];
194 a->d[i] = (a->d[i] - w) & BN_MASK2;
199 if ((a->d[i] == 0) && (i == (a->top - 1)))
205 int BN_mul_word(BIGNUM *a, BN_ULONG w)
215 ll = bn_mul_words(a->d, a->d, a->top, w);
217 if (bn_wexpand(a, a->top + 1) == NULL)