OpenWrt – Rev 4
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/* crypto/bn/bn_sqr.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.]
*/
#include <stdio.h>
#include <string.h>
#include "bn_lcl.h"
/* r must not be a */
/* I've just gone over this and it is now %20 faster on x86 - eay - 27 Jun 96 */
int BN_sqr(BIGNUM *r, BIGNUM *a, BN_CTX *ctx)
{
int max,al;
int ret = 0;
BIGNUM *tmp,*rr;
#ifdef BN_COUNT
printf("BN_sqr %d * %d\n",a->top,a->top);
#endif
bn_check_top(a);
al=a->top;
if (al <= 0)
{
r->top=0;
return(1);
}
BN_CTX_start(ctx);
rr=(a != r) ? r : BN_CTX_get(ctx);
tmp=BN_CTX_get(ctx);
if (tmp == NULL) goto err;
max=(al+al);
if (bn_wexpand(rr,max+1) == NULL) goto err;
r->neg=0;
if (al == 4)
{
#ifndef BN_SQR_COMBA
BN_ULONG t[8];
bn_sqr_normal(rr->d,a->d,4,t);
#else
bn_sqr_comba4(rr->d,a->d);
#endif
}
else if (al == 8)
{
#ifndef BN_SQR_COMBA
BN_ULONG t[16];
bn_sqr_normal(rr->d,a->d,8,t);
#else
bn_sqr_comba8(rr->d,a->d);
#endif
}
else
{
if (bn_wexpand(tmp,max) == NULL) goto err;
bn_sqr_normal(rr->d,a->d,al,tmp->d);
}
rr->top=max;
if ((max > 0) && (rr->d[max-1] == 0)) rr->top--;
if (rr != r) BN_copy(r,rr);
ret = 1;
err:
BN_CTX_end(ctx);
return(ret);
}
/* tmp must have 2*n words */
void bn_sqr_normal(BN_ULONG *r, BN_ULONG *a, int n, BN_ULONG *tmp)
{
int i,j,max;
BN_ULONG *ap,*rp;
max=n*2;
ap=a;
rp=r;
rp[0]=rp[max-1]=0;
rp++;
j=n;
if (--j > 0)
{
ap++;
rp[j]=bn_mul_words(rp,ap,j,ap[-1]);
rp+=2;
}
for (i=n-2; i>0; i--)
{
j--;
ap++;
rp[j]=bn_mul_add_words(rp,ap,j,ap[-1]);
rp+=2;
}
bn_add_words(r,r,r,max);
/* There will not be a carry */
bn_sqr_words(tmp,a,n);
bn_add_words(r,r,tmp,max);
}