package/ead/src/tinysrp/bn_mul.c

   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
  63 int 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 #ifdef BN_RECURSION
  72         BIGNUM *t;
  73         int j,k;
  74 #endif
  75
  76 #ifdef BN_COUNT
  77         printf("BN_mul %d * %d\n",a->top,b->top);
  78 #endif
  79
  80         bn_check_top(a);
  81         bn_check_top(b);
  82         bn_check_top(r);
  83
  84         al=a->top;
  85         bl=b->top;
  86
  87         if ((al == 0) || (bl == 0))
  88                 {
  89                 BN_zero(r);
  90                 return(1);
  91                 }
  92         top=al+bl;
  93
  94         BN_CTX_start(ctx);
  95         if ((r == a) || (r == b))
  96                 {
  97                 if ((rr = BN_CTX_get(ctx)) == NULL) goto err;
  98                 }
  99         else
 100                 rr = r;
 101         rr->neg=a->neg^b->neg;
 102
 103 #if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
 104         i = al-bl;
 105 #endif
 106 #ifdef BN_MUL_COMBA
 107         if (i == 0)
 108                 {
 109 # if 0
 110                 if (al == 4)
 111                         {
 112                         if (bn_wexpand(rr,8) == NULL) goto err;
 113                         rr->top=8;
 114                         bn_mul_comba4(rr->d,a->d,b->d);
 115                         goto end;
 116                         }
 117 # endif
 118                 if (al == 8)
 119                         {
 120                         if (bn_wexpand(rr,16) == NULL) goto err;
 121                         rr->top=16;
 122                         bn_mul_comba8(rr->d,a->d,b->d);
 123                         goto end;
 124                         }
 125                 }
 126 #endif /* BN_MUL_COMBA */
 127         if (bn_wexpand(rr,top) == NULL) goto err;
 128         rr->top=top;
 129         bn_mul_normal(rr->d,a->d,al,b->d,bl);
 130
 131 #if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
 132 end:
 133 #endif
 134         bn_fix_top(rr);
 135         if (r != rr) BN_copy(r,rr);
 136         ret=1;
 137 err:
 138         BN_CTX_end(ctx);
 139         return(ret);
 140         }
 141
 142 void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b, int nb)
 143         {
 144         BN_ULONG *rr;
 145
 146 #ifdef BN_COUNT
 147         printf(" bn_mul_normal %d * %d\n",na,nb);
 148 #endif
 149
 150         if (na < nb)
 151                 {
 152                 int itmp;
 153                 BN_ULONG *ltmp;
 154
 155                 itmp=na; na=nb; nb=itmp;
 156                 ltmp=a;   a=b;   b=ltmp;
 157
 158                 }
 159         rr= &(r[na]);
 160         rr[0]=bn_mul_words(r,a,na,b[0]);
 161
 162         for (;;)
 163                 {
 164                 if (--nb <= 0) return;
 165                 rr[1]=bn_mul_add_words(&(r[1]),a,na,b[1]);
 166                 if (--nb <= 0) return;
 167                 rr[2]=bn_mul_add_words(&(r[2]),a,na,b[2]);
 168                 if (--nb <= 0) return;
 169                 rr[3]=bn_mul_add_words(&(r[3]),a,na,b[3]);
 170                 if (--nb <= 0) return;
 171                 rr[4]=bn_mul_add_words(&(r[4]),a,na,b[4]);
 172                 rr+=4;
 173                 r+=4;
 174                 b+=4;
 175                 }
 176         }