package/ead/src/tinysrp/bn_sqr.c

   1 /* crypto/bn/bn_sqr.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 /* r must not be a */
  64 /* I've just gone over this and it is now %20 faster on x86 - eay - 27 Jun 96 */
  65 int BN_sqr(BIGNUM *r, BIGNUM *a, BN_CTX *ctx)
  66         {
  67         int max,al;
  68         int ret = 0;
  69         BIGNUM *tmp,*rr;
  70
  71 #ifdef BN_COUNT
  72 printf("BN_sqr %d * %d\n",a->top,a->top);
  73 #endif
  74         bn_check_top(a);
  75
  76         al=a->top;
  77         if (al <= 0)
  78                 {
  79                 r->top=0;
  80                 return(1);
  81                 }
  82
  83         BN_CTX_start(ctx);
  84         rr=(a != r) ? r : BN_CTX_get(ctx);
  85         tmp=BN_CTX_get(ctx);
  86         if (tmp == NULL) goto err;
  87
  88         max=(al+al);
  89         if (bn_wexpand(rr,max+1) == NULL) goto err;
  90
  91         r->neg=0;
  92         if (al == 4)
  93                 {
  94 #ifndef BN_SQR_COMBA
  95                 BN_ULONG t[8];
  96                 bn_sqr_normal(rr->d,a->d,4,t);
  97 #else
  98                 bn_sqr_comba4(rr->d,a->d);
  99 #endif
 100                 }
 101         else if (al == 8)
 102                 {
 103 #ifndef BN_SQR_COMBA
 104                 BN_ULONG t[16];
 105                 bn_sqr_normal(rr->d,a->d,8,t);
 106 #else
 107                 bn_sqr_comba8(rr->d,a->d);
 108 #endif
 109                 }
 110         else
 111                 {
 112                 if (bn_wexpand(tmp,max) == NULL) goto err;
 113                 bn_sqr_normal(rr->d,a->d,al,tmp->d);
 114                 }
 115
 116         rr->top=max;
 117         if ((max > 0) && (rr->d[max-1] == 0)) rr->top--;
 118         if (rr != r) BN_copy(r,rr);
 119         ret = 1;
 120  err:
 121         BN_CTX_end(ctx);
 122         return(ret);
 123         }
 124
 125 /* tmp must have 2*n words */
 126 void bn_sqr_normal(BN_ULONG *r, BN_ULONG *a, int n, BN_ULONG *tmp)
 127         {
 128         int i,j,max;
 129         BN_ULONG *ap,*rp;
 130
 131         max=n*2;
 132         ap=a;
 133         rp=r;
 134         rp[0]=rp[max-1]=0;
 135         rp++;
 136         j=n;
 137
 138         if (--j > 0)
 139                 {
 140                 ap++;
 141                 rp[j]=bn_mul_words(rp,ap,j,ap[-1]);
 142                 rp+=2;
 143                 }
 144
 145         for (i=n-2; i>0; i--)
 146                 {
 147                 j--;
 148                 ap++;
 149                 rp[j]=bn_mul_add_words(rp,ap,j,ap[-1]);
 150                 rp+=2;
 151                 }
 152
 153         bn_add_words(r,r,r,max);
 154
 155         /* There will not be a carry */
 156
 157         bn_sqr_words(tmp,a,n);
 158
 159         bn_add_words(r,r,tmp,max);
 160         }