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60f18e5554
git-svn-id: file:///Users/lillianskinner/Downloads/platinum/twl/TwlIPL/trunk@1 b08762b0-b915-fc4b-9d8c-17b2551a87ff
124 lines
2.2 KiB
C
124 lines
2.2 KiB
C
/* $Id$ */
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/*
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* Copyright (C) 1998-2002 RSA Security Inc. All rights reserved.
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*
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* This work contains proprietary information of RSA Security.
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* Distribution is limited to authorized licensees of RSA
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* Security. Any unauthorized reproduction, distribution or
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* modification of this work is strictly prohibited.
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*
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*/
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#include "bn_lcl.h"
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#if !(defined(NO_SPLIT) && defined(SPLIT_FILE))
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#ifdef NO_SPLIT
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#define SPLIT_BN_RSHIFT1
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#define SPLIT_BN_RSHIFT
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#endif /* NO_SPLIT */
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#ifdef SPLIT_BN_RSHIFT1
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#ifdef SMALL_CODE_SIZE
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int BN_rshift1(r, a)
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BIGNUM *r;
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BIGNUM *a;
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{
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return(BN_rshift(r,a,1));
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}
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#else
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int BN_rshift1(r, a)
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BIGNUM *r;
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BIGNUM *a;
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{
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BN_ULONG *ap,*rp,t,c;
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int i;
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bn_check_top(a);
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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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if (a != r)
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{
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if (bn_wexpand(r,a->top) == NULL) return(0);
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r->top=a->top;
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r->neg=a->neg;
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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=a->top-1; i>=0; i--)
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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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bn_fix_top(r);
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return(1);
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}
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#endif
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#endif
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#ifdef SPLIT_BN_RSHIFT
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int BN_rshift(r, a, n)
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BIGNUM *r;
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BIGNUM *a;
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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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bn_check_top(a);
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#ifndef SMALL_CODE_SIZE
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if (n == 1) return(BN_rshift1(r,a));
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#endif
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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)
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{
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(void)BN_zero(r);
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return(1);
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}
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if (r != a)
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{
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if (bn_wexpand(r,a->top-nw+1+1/*???*/) == NULL) return(0);
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r->neg=a->neg;
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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=j;
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if (rb == 0)
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{
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for (i=j+1; 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=1; i<j; 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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*(t++) =(l>>rb)&BN_MASK2;
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*t=0;
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}
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bn_fix_top(r);
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return(1);
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}
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#endif
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#endif
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