223 lines
5.7 KiB
C
Executable File
223 lines
5.7 KiB
C
Executable File
/* crypto/bn/bn_shift.c */
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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
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* All rights reserved.
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*
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* This package is an SSL implementation written
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* by Eric Young (eay@cryptsoft.com).
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* The implementation was written so as to conform with Netscapes SSL.
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*
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* This library is free for commercial and non-commercial use as long as
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* the following conditions are aheared to. The following conditions
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* apply to all code found in this distribution, be it the RC4, RSA,
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* lhash, DES, etc., code; not just the SSL code. The SSL documentation
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* included with this distribution is covered by the same copyright terms
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* except that the holder is Tim Hudson (tjh@cryptsoft.com).
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*
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* Copyright remains Eric Young's, and as such any Copyright notices in
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* the code are not to be removed.
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* If this package is used in a product, Eric Young should be given attribution
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* as the author of the parts of the library used.
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* This can be in the form of a textual message at program startup or
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* in documentation (online or textual) provided with the package.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* "This product includes cryptographic software written by
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* Eric Young (eay@cryptsoft.com)"
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* The word 'cryptographic' can be left out if the rouines from the library
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* being used are not cryptographic related :-).
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* 4. If you include any Windows specific code (or a derivative thereof) from
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* the apps directory (application code) you must include an acknowledgement:
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* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
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*
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* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* The licence and distribution terms for any publically available version or
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* derivative of this code cannot be changed. i.e. this code cannot simply be
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* copied and put under another distribution licence
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* [including the GNU Public Licence.]
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*/
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#include "cryptlib.h"
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#include "bn_lcl.h"
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//int BN_lshift1(BIGNUM *r, const BIGNUM *a)
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// {
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// register BN_ULONG *ap,*rp,t,c;
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// int i;
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//
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// bn_check_top(r);
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// bn_check_top(a);
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//
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// if (r != a)
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// {
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// r->neg=a->neg;
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// if (bn_wexpand(r,a->top+1) == NULL) return(0);
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// r->top=a->top;
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// }
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// else
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// {
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// if (bn_wexpand(r,a->top+1) == NULL) return(0);
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// }
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// ap=a->d;
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// rp=r->d;
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// c=0;
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// for (i=0; i<a->top; i++)
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// {
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// t= *(ap++);
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// *(rp++)=((t<<1)|c)&BN_MASK2;
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// c=(t & BN_TBIT)?1:0;
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// }
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// if (c)
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// {
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// *rp=1;
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// r->top++;
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// }
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// bn_check_top(r);
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// return(1);
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// }
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//int BN_rshift1(BIGNUM *r, const BIGNUM *a)
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// {
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// BN_ULONG *ap,*rp,t,c;
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// int i,j;
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//
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// bn_check_top(r);
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// bn_check_top(a);
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//
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// if (BN_is_zero(a))
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// {
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// BN_zero(r);
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// return(1);
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// }
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// i = a->top;
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// ap= a->d;
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// j = i-(ap[i-1]==1);
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// if (a != r)
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// {
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// if (bn_wexpand(r,j) == NULL) return(0);
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// r->neg=a->neg;
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// }
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// rp=r->d;
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// t=ap[--i];
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// c=(t&1)?BN_TBIT:0;
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// if (t>>=1) rp[i]=t;
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// while (i>0)
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// {
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// t=ap[--i];
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// rp[i]=((t>>1)&BN_MASK2)|c;
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// c=(t&1)?BN_TBIT:0;
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// }
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// r->top=j;
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// bn_check_top(r);
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// return(1);
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// }
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int BN_lshift(BIGNUM *r, const BIGNUM *a, int n)
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{
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int i,nw,lb,rb;
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BN_ULONG *t,*f;
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BN_ULONG l;
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bn_check_top(r);
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bn_check_top(a);
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r->neg=a->neg;
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nw=n/BN_BITS2;
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if (bn_wexpand(r,a->top+nw+1) == NULL) return(0);
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lb=n%BN_BITS2;
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rb=BN_BITS2-lb;
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f=a->d;
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t=r->d;
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t[a->top+nw]=0;
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if (lb == 0)
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for (i=a->top-1; i>=0; i--)
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t[nw+i]=f[i];
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else
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for (i=a->top-1; i>=0; i--)
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{
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l=f[i];
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t[nw+i+1]|=(l>>rb)&BN_MASK2;
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t[nw+i]=(l<<lb)&BN_MASK2;
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}
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memset(t,0,nw*sizeof(t[0]));
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/* for (i=0; i<nw; i++)
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t[i]=0;*/
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r->top=a->top+nw+1;
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bn_correct_top(r);
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bn_check_top(r);
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return(1);
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}
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//int BN_rshift(BIGNUM *r, const BIGNUM *a, int n)
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// {
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// int i,j,nw,lb,rb;
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// BN_ULONG *t,*f;
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// BN_ULONG l,tmp;
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//
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// bn_check_top(r);
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// bn_check_top(a);
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//
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// nw=n/BN_BITS2;
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// rb=n%BN_BITS2;
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// lb=BN_BITS2-rb;
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// if (nw >= a->top || a->top == 0)
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// {
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// BN_zero(r);
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// return(1);
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// }
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// i = (BN_num_bits(a)-n+(BN_BITS2-1))/BN_BITS2;
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// if (r != a)
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// {
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// r->neg=a->neg;
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// if (bn_wexpand(r,i) == NULL) return(0);
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// }
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// else
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// {
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// if (n == 0)
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// return 1; /* or the copying loop will go berserk */
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// }
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//
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// f= &(a->d[nw]);
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// t=r->d;
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// j=a->top-nw;
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// r->top=i;
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//
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// if (rb == 0)
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// {
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// for (i=j; i != 0; i--)
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// *(t++)= *(f++);
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// }
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// else
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// {
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// l= *(f++);
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// for (i=j-1; i != 0; i--)
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// {
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// tmp =(l>>rb)&BN_MASK2;
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// l= *(f++);
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// *(t++) =(tmp|(l<<lb))&BN_MASK2;
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// }
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// if ((l = (l>>rb)&BN_MASK2)) *(t) = l;
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// }
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// bn_check_top(r);
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// return(1);
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// }
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