1/* crypto/bn/bn_word.c */ 2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 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 63BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w) 64 { 65#ifndef BN_LLONG 66 BN_ULONG ret=0; 67#else 68 BN_ULLONG ret=0; 69#endif 70 int i; 71 72 w&=BN_MASK2; 73 for (i=a->top-1; i>=0; i--) 74 { 75#ifndef BN_LLONG 76 ret=((ret<<BN_BITS4)|((a->d[i]>>BN_BITS4)&BN_MASK2l))%w; 77 ret=((ret<<BN_BITS4)|(a->d[i]&BN_MASK2l))%w; 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 86BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w) 87 { 88 BN_ULONG ret; 89 int i; 90 91 if (a->top == 0) return(0); 92 ret=0; 93 w&=BN_MASK2; 94 for (i=a->top-1; i>=0; i--) 95 { 96 BN_ULONG l,d; 97 98 l=a->d[i]; 99 d=bn_div_words(ret,l,w); 100 ret=(l-((d*w)&BN_MASK2))&BN_MASK2; 101 a->d[i]=d; 102 } 103 if ((a->top > 0) && (a->d[a->top-1] == 0)) 104 a->top--; 105 return(ret); 106 } 107 108int BN_add_word(BIGNUM *a, BN_ULONG w) 109 { 110 BN_ULONG l; 111 int i; 112 113 if (a->neg) 114 { 115 a->neg=0; 116 i=BN_sub_word(a,w); 117 if (!BN_is_zero(a)) 118 a->neg=!(a->neg); 119 return(i); 120 } 121 w&=BN_MASK2; 122 if (bn_wexpand(a,a->top+1) == NULL) return(0); 123 i=0; 124 for (;;) 125 { 126 if (i >= a->top) 127 l=w; 128 else 129 l=(a->d[i]+(BN_ULONG)w)&BN_MASK2; 130 a->d[i]=l; 131 if (w > l) 132 w=1; 133 else 134 break; 135 i++; 136 } 137 if (i >= a->top) 138 a->top++; 139 return(1); 140 } 141 142int BN_sub_word(BIGNUM *a, BN_ULONG w) 143 { 144 int i; 145 146 if (BN_is_zero(a) || a->neg) 147 { 148 a->neg=0; 149 i=BN_add_word(a,w); 150 a->neg=1; 151 return(i); 152 } 153 154 w&=BN_MASK2; 155 if ((a->top == 1) && (a->d[0] < w)) 156 { 157 a->d[0]=w-a->d[0]; 158 a->neg=1; 159 return(1); 160 } 161 i=0; 162 for (;;) 163 { 164 if (a->d[i] >= w) 165 { 166 a->d[i]-=w; 167 break; 168 } 169 else 170 { 171 a->d[i]=(a->d[i]-w)&BN_MASK2; 172 i++; 173 w=1; 174 } 175 } 176 if ((a->d[i] == 0) && (i == (a->top-1))) 177 a->top--; 178 return(1); 179 } 180 181int BN_mul_word(BIGNUM *a, BN_ULONG w) 182 { 183 BN_ULONG ll; 184 185 w&=BN_MASK2; 186 if (a->top) 187 { 188 if (w == 0) 189 BN_zero(a); 190 else 191 { 192 ll=bn_mul_words(a->d,a->d,a->top,w); 193 if (ll) 194 { 195 if (bn_wexpand(a,a->top+1) == NULL) return(0); 196 a->d[a->top++]=ll; 197 } 198 } 199 } 200 return(1); 201 } 202 203