1/* crypto/bn/bn_mul.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 <string.h> 61#include "bn_lcl.h" 62 63int BN_mul(BIGNUM *r, BIGNUM *a, BIGNUM *b, BN_CTX *ctx) 64 { 65 int top,al,bl; 66 BIGNUM *rr; 67 int ret = 0; 68#if defined(BN_MUL_COMBA) || defined(BN_RECURSION) 69 int i; 70#endif 71 72#ifdef BN_COUNT 73 printf("BN_mul %d * %d\n",a->top,b->top); 74#endif 75 76 bn_check_top(a); 77 bn_check_top(b); 78 bn_check_top(r); 79 80 al=a->top; 81 bl=b->top; 82 83 if ((al == 0) || (bl == 0)) 84 { 85 BN_zero(r); 86 return(1); 87 } 88 top=al+bl; 89 90 BN_CTX_start(ctx); 91 if ((r == a) || (r == b)) 92 { 93 if ((rr = BN_CTX_get(ctx)) == NULL) goto err; 94 } 95 else 96 rr = r; 97 rr->neg=a->neg^b->neg; 98 99#if defined(BN_MUL_COMBA) || defined(BN_RECURSION) 100 i = al-bl; 101#endif 102#ifdef BN_MUL_COMBA 103 if (i == 0) 104 { 105# if 0 106 if (al == 4) 107 { 108 if (bn_wexpand(rr,8) == NULL) goto err; 109 rr->top=8; 110 bn_mul_comba4(rr->d,a->d,b->d); 111 goto end; 112 } 113# endif 114 if (al == 8) 115 { 116 if (bn_wexpand(rr,16) == NULL) goto err; 117 rr->top=16; 118 bn_mul_comba8(rr->d,a->d,b->d); 119 goto end; 120 } 121 } 122#endif /* BN_MUL_COMBA */ 123 if (bn_wexpand(rr,top) == NULL) goto err; 124 rr->top=top; 125 bn_mul_normal(rr->d,a->d,al,b->d,bl); 126 127#if defined(BN_MUL_COMBA) || defined(BN_RECURSION) 128end: 129#endif 130 bn_fix_top(rr); 131 if (r != rr) BN_copy(r,rr); 132 ret=1; 133err: 134 BN_CTX_end(ctx); 135 return(ret); 136 } 137 138void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b, int nb) 139 { 140 BN_ULONG *rr; 141 142#ifdef BN_COUNT 143 printf(" bn_mul_normal %d * %d\n",na,nb); 144#endif 145 146 if (na < nb) 147 { 148 int itmp; 149 BN_ULONG *ltmp; 150 151 itmp=na; na=nb; nb=itmp; 152 ltmp=a; a=b; b=ltmp; 153 154 } 155 rr= &(r[na]); 156 rr[0]=bn_mul_words(r,a,na,b[0]); 157 158 for (;;) 159 { 160 if (--nb <= 0) return; 161 rr[1]=bn_mul_add_words(&(r[1]),a,na,b[1]); 162 if (--nb <= 0) return; 163 rr[2]=bn_mul_add_words(&(r[2]),a,na,b[2]); 164 if (--nb <= 0) return; 165 rr[3]=bn_mul_add_words(&(r[3]),a,na,b[3]); 166 if (--nb <= 0) return; 167 rr[4]=bn_mul_add_words(&(r[4]),a,na,b[4]); 168 rr+=4; 169 r+=4; 170 b+=4; 171 } 172 } 173