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- Committer: Bazaar Package Importer
- Author(s): Tomas Fasth
- Date: 2005-05-24 13:31:34 UTC
- mfrom: (1.1.1 upstream)
- Revision ID: james.westby@ubuntu.com-20050524133134-6hn24gprfmo91sfv
Tags: 1.4.1-1
New upstream release.
- files added:
- Makefile.in
- files removed:
- ChangeLog
- crypto
- files modified:
- README
- doc/keymap-names.txt *
added
removed
crypto/bn_div.c
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/* crypto/bn/bn_div.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 <stdio.h>
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#include "bn.h"
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#include "bn_lcl.h"
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/* The old slow way */
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#if 0
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int BN_div(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m, const BIGNUM *d,
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BN_CTX *ctx)
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{
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int i,nm,nd;
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int ret = 0;
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BIGNUM *D;
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bn_check_top(m);
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bn_check_top(d);
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if (BN_is_zero(d))
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{
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BNerr(BN_F_BN_DIV,BN_R_DIV_BY_ZERO);
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return(0);
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}
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if (BN_ucmp(m,d) < 0)
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{
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if (rem != NULL)
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{ if (BN_copy(rem,m) == NULL) return(0); }
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if (dv != NULL) BN_zero(dv);
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return(1);
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}
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BN_CTX_start(ctx);
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D = BN_CTX_get(ctx);
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if (dv == NULL) dv = BN_CTX_get(ctx);
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if (rem == NULL) rem = BN_CTX_get(ctx);
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if (D == NULL || dv == NULL || rem == NULL)
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goto end;
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nd=BN_num_bits(d);
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nm=BN_num_bits(m);
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if (BN_copy(D,d) == NULL) goto end;
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if (BN_copy(rem,m) == NULL) goto end;
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/* The next 2 are needed so we can do a dv->d[0]|=1 later
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* since BN_lshift1 will only work once there is a value :-) */
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BN_zero(dv);
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bn_wexpand(dv,1);
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dv->top=1;
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if (!BN_lshift(D,D,nm-nd)) goto end;
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for (i=nm-nd; i>=0; i--)
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{
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if (!BN_lshift1(dv,dv)) goto end;
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if (BN_ucmp(rem,D) >= 0)
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{
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dv->d[0]|=1;
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if (!BN_usub(rem,rem,D)) goto end;
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}
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/* CAN IMPROVE (and have now :=) */
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if (!BN_rshift1(D,D)) goto end;
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}
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rem->neg=BN_is_zero(rem)?0:m->neg;
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dv->neg=m->neg^d->neg;
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ret = 1;
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end:
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BN_CTX_end(ctx);
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return(ret);
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}
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126
#else
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#if !defined(NO_ASM) && !defined(NO_INLINE_ASM) && !defined(PEDANTIC) && !defined(BN_DIV3W)
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# if defined(__GNUC__) && __GNUC__>=2
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# if defined(__i386) || defined (__i386__)
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/*
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* There were two reasons for implementing this template:
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* - GNU C generates a call to a function (__udivdi3 to be exact)
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* in reply to ((((BN_ULLONG)n0)<<BN_BITS2)|n1)/d0 (I fail to
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* understand why...);
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* - divl doesn't only calculate quotient, but also leaves
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* remainder in %edx which we can definitely use here:-)
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*
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* <appro@fy.chalmers.se>
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*/
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# define bn_div_words(n0,n1,d0) \
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({ asm volatile ( \
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"divl %4" \
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: "=a"(q), "=d"(rem) \
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: "a"(n1), "d"(n0), "g"(d0) \
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: "cc"); \
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q; \
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})
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# define REMAINDER_IS_ALREADY_CALCULATED
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# endif /* __<cpu> */
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# endif /* __GNUC__ */
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#endif /* NO_ASM */
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154
int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
155
BN_CTX *ctx)
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{
157
int norm_shift,i,j,loop;
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BIGNUM *tmp,wnum,*snum,*sdiv,*res;
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BN_ULONG *resp,*wnump;
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BN_ULONG d0,d1;
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int num_n,div_n;
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163
bn_check_top(num);
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bn_check_top(divisor);
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166
if (BN_is_zero(divisor))
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{
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BNerr(BN_F_BN_DIV,BN_R_DIV_BY_ZERO);
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return(0);
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}
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if (BN_ucmp(num,divisor) < 0)
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{
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if (rm != NULL)
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{ if (BN_copy(rm,num) == NULL) return(0); }
176
if (dv != NULL) BN_zero(dv);
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return(1);
178
}
179
180
BN_CTX_start(ctx);
181
tmp=BN_CTX_get(ctx);
182
snum=BN_CTX_get(ctx);
183
sdiv=BN_CTX_get(ctx);
184
if (dv == NULL)
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res=BN_CTX_get(ctx);
186
else res=dv;
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if (sdiv==NULL || res == NULL) goto err;
188
tmp->neg=0;
189
190
/* First we normalise the numbers */
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norm_shift=BN_BITS2-((BN_num_bits(divisor))%BN_BITS2);
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if (!(BN_lshift(sdiv,divisor,norm_shift))) goto err;
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sdiv->neg=0;
194
norm_shift+=BN_BITS2;
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if (!(BN_lshift(snum,num,norm_shift))) goto err;
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snum->neg=0;
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div_n=sdiv->top;
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num_n=snum->top;
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loop=num_n-div_n;
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/* Lets setup a 'window' into snum
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* This is the part that corresponds to the current
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* 'area' being divided */
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BN_init(&wnum);
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wnum.d= &(snum->d[loop]);
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wnum.top= div_n;
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wnum.dmax= snum->dmax+1; /* a bit of a lie */
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/* Get the top 2 words of sdiv */
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/* i=sdiv->top; */
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d0=sdiv->d[div_n-1];
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d1=(div_n == 1)?0:sdiv->d[div_n-2];
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/* pointer to the 'top' of snum */
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wnump= &(snum->d[num_n-1]);
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/* Setup to 'res' */
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res->neg= (num->neg^divisor->neg);
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if (!bn_wexpand(res,(loop+1))) goto err;
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res->top=loop;
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resp= &(res->d[loop-1]);
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/* space for temp */
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if (!bn_wexpand(tmp,(div_n+1))) goto err;
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if (BN_ucmp(&wnum,sdiv) >= 0)
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{
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if (!BN_usub(&wnum,&wnum,sdiv)) goto err;
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*resp=1;
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res->d[res->top-1]=1;
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}
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else
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res->top--;
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resp--;
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for (i=0; i<loop-1; i++)
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{
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BN_ULONG q,l0;
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#if defined(BN_DIV3W) && !defined(NO_ASM)
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BN_ULONG bn_div_3_words(BN_ULONG*,BN_ULONG,BN_ULONG);
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q=bn_div_3_words(wnump,d1,d0);
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#else
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BN_ULONG n0,n1,rem=0;
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245
n0=wnump[0];
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n1=wnump[-1];
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if (n0 == d0)
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q=BN_MASK2;
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else /* n0 < d0 */
250
{
251
#ifdef BN_LLONG
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BN_ULLONG t2;
253
254
#if defined(BN_LLONG) && defined(BN_DIV2W) && !defined(bn_div_words)
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q=(BN_ULONG)(((((BN_ULLONG)n0)<<BN_BITS2)|n1)/d0);
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#else
257
q=bn_div_words(n0,n1,d0);
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#endif
259
260
#ifndef REMAINDER_IS_ALREADY_CALCULATED
261
/*
262
* rem doesn't have to be BN_ULLONG. The least we
263
* know it's less that d0, isn't it?
264
*/
265
rem=(n1-q*d0)&BN_MASK2;
266
#endif
267
t2=(BN_ULLONG)d1*q;
268
269
for (;;)
270
{
271
if (t2 <= ((((BN_ULLONG)rem)<<BN_BITS2)|wnump[-2]))
272
break;
273
q--;
274
rem += d0;
275
if (rem < d0) break; /* don't let rem overflow */
276
t2 -= d1;
277
}
278
#else /* !BN_LLONG */
279
BN_ULONG t2l,t2h,ql,qh;
280
281
q=bn_div_words(n0,n1,d0);
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#ifndef REMAINDER_IS_ALREADY_CALCULATED
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rem=(n1-q*d0)&BN_MASK2;
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#endif
285
286
#ifdef BN_UMULT_HIGH
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t2l = d1 * q;
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t2h = BN_UMULT_HIGH(d1,q);
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#else
290
t2l=LBITS(d1); t2h=HBITS(d1);
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ql =LBITS(q); qh =HBITS(q);
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mul64(t2l,t2h,ql,qh); /* t2=(BN_ULLONG)d1*q; */
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#endif
294
295
for (;;)
296
{
297
if ((t2h < rem) ||
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((t2h == rem) && (t2l <= wnump[-2])))
299
break;
300
q--;
301
rem += d0;
302
if (rem < d0) break; /* don't let rem overflow */
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if (t2l < d1) t2h--; t2l -= d1;
304
}
305
#endif /* !BN_LLONG */
306
}
307
#endif /* !BN_DIV3W */
308
309
l0=bn_mul_words(tmp->d,sdiv->d,div_n,q);
310
wnum.d--; wnum.top++;
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tmp->d[div_n]=l0;
312
for (j=div_n+1; j>0; j--)
313
if (tmp->d[j-1]) break;
314
tmp->top=j;
315
316
j=wnum.top;
317
if (!BN_sub(&wnum,&wnum,tmp)) goto err;
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319
snum->top=snum->top+wnum.top-j;
320
321
if (wnum.neg)
322
{
323
q--;
324
j=wnum.top;
325
if (!BN_add(&wnum,&wnum,sdiv)) goto err;
326
snum->top+=wnum.top-j;
327
}
328
*(resp--)=q;
329
wnump--;
330
}
331
if (rm != NULL)
332
{
333
BN_rshift(rm,snum,norm_shift);
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rm->neg=num->neg;
335
}
336
BN_CTX_end(ctx);
337
return(1);
338
err:
339
BN_CTX_end(ctx);
340
return(0);
341
}
342
343
#endif
344
345
/* rem != m */
346
int BN_mod(BIGNUM *rem, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx)
347
{
348
#if 0 /* The old slow way */
349
int i,nm,nd;
350
BIGNUM *dv;
351
352
if (BN_ucmp(m,d) < 0)
353
return((BN_copy(rem,m) == NULL)?0:1);
354
355
BN_CTX_start(ctx);
356
dv=BN_CTX_get(ctx);
357
358
if (!BN_copy(rem,m)) goto err;
359
360
nm=BN_num_bits(rem);
361
nd=BN_num_bits(d);
362
if (!BN_lshift(dv,d,nm-nd)) goto err;
363
for (i=nm-nd; i>=0; i--)
364
{
365
if (BN_cmp(rem,dv) >= 0)
366
{
367
if (!BN_sub(rem,rem,dv)) goto err;
368
}
369
if (!BN_rshift1(dv,dv)) goto err;
370
}
371
BN_CTX_end(ctx);
372
return(1);
373
err:
374
BN_CTX_end(ctx);
375
return(0);
376
#else
377
return(BN_div(NULL,rem,m,d,ctx));
378
#endif
379
}
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