/* * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved. * * The contents of this file constitute Original Code as defined in and are * subject to the Apple Public Source License Version 1.2 (the 'License'). * You may not use this file except in compliance with the License. Please obtain * a copy of the License at http://www.apple.com/publicsource and read it before * using this file. * * This Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the * specific language governing rights and limitations under the License. */ /* crypto/bn/bn_div.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 <openssl/bn.h> #include "cryptlib.h" #include "bn_lcl.h" /* The old slow way */ #if 0 int BN_div(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx) { int i,nm,nd; int ret = 0; BIGNUM *D; bn_check_top(m); bn_check_top(d); if (BN_is_zero(d)) { BNerr(BN_F_BN_DIV,BN_R_DIV_BY_ZERO); return(0); } if (BN_ucmp(m,d) < 0) { if (rem != NULL) { if (BN_copy(rem,m) == NULL) return(0); } if (dv != NULL) BN_zero(dv); return(1); } BN_CTX_start(ctx); D = BN_CTX_get(ctx); if (dv == NULL) dv = BN_CTX_get(ctx); if (rem == NULL) rem = BN_CTX_get(ctx); if (D == NULL || dv == NULL || rem == NULL) goto end; nd=BN_num_bits(d); nm=BN_num_bits(m); if (BN_copy(D,d) == NULL) goto end; if (BN_copy(rem,m) == NULL) goto end; /* The next 2 are needed so we can do a dv->d[0]|=1 later * since BN_lshift1 will only work once there is a value :-) */ BN_zero(dv); bn_wexpand(dv,1); dv->top=1; if (!BN_lshift(D,D,nm-nd)) goto end; for (i=nm-nd; i>=0; i--) { if (!BN_lshift1(dv,dv)) goto end; if (BN_ucmp(rem,D) >= 0) { dv->d[0]|=1; if (!BN_usub(rem,rem,D)) goto end; } /* CAN IMPROVE (and have now :=) */ if (!BN_rshift1(D,D)) goto end; } rem->neg=BN_is_zero(rem)?0:m->neg; dv->neg=m->neg^d->neg; ret = 1; end: BN_CTX_end(ctx); return(ret); } #else #if !defined(NO_ASM) && !defined(NO_INLINE_ASM) && !defined(PEDANTIC) && !defined(BN_DIV3W) # if defined(__GNUC__) && __GNUC__>=2 # if defined(__i386) /* * There were two reasons for implementing this template: * - GNU C generates a call to a function (__udivdi3 to be exact) * in reply to ((((BN_ULLONG)n0)<<BN_BITS2)|n1)/d0 (I fail to * understand why...); * - divl doesn't only calculate quotient, but also leaves * remainder in %edx which we can definitely use here:-) * * <appro@fy.chalmers.se> */ # define bn_div_words(n0,n1,d0) \ ({ asm volatile ( \ "divl %4" \ : "=a"(q), "=d"(rem) \ : "a"(n1), "d"(n0), "g"(d0) \ : "cc"); \ q; \ }) # define REMAINDER_IS_ALREADY_CALCULATED # endif /* __<cpu> */ # endif /* __GNUC__ */ #endif /* NO_ASM */ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor, BN_CTX *ctx) { int norm_shift,i,j,loop; BIGNUM *tmp,wnum,*snum,*sdiv,*res; BN_ULONG *resp,*wnump; BN_ULONG d0,d1; int num_n,div_n; bn_check_top(num); bn_check_top(divisor); if (BN_is_zero(divisor)) { BNerr(BN_F_BN_DIV,BN_R_DIV_BY_ZERO); return(0); } if (BN_ucmp(num,divisor) < 0) { if (rm != NULL) { if (BN_copy(rm,num) == NULL) return(0); } if (dv != NULL) BN_zero(dv); return(1); } BN_CTX_start(ctx); tmp=BN_CTX_get(ctx); tmp->neg=0; snum=BN_CTX_get(ctx); sdiv=BN_CTX_get(ctx); if (dv == NULL) res=BN_CTX_get(ctx); else res=dv; if (res == NULL) goto err; /* First we normalise the numbers */ norm_shift=BN_BITS2-((BN_num_bits(divisor))%BN_BITS2); BN_lshift(sdiv,divisor,norm_shift); sdiv->neg=0; norm_shift+=BN_BITS2; BN_lshift(snum,num,norm_shift); snum->neg=0; div_n=sdiv->top; num_n=snum->top; loop=num_n-div_n; /* Lets setup a 'window' into snum * This is the part that corresponds to the current * 'area' being divided */ BN_init(&wnum); wnum.d= &(snum->d[loop]); wnum.top= div_n; wnum.max= snum->max+1; /* a bit of a lie */ /* Get the top 2 words of sdiv */ /* i=sdiv->top; */ d0=sdiv->d[div_n-1]; d1=(div_n == 1)?0:sdiv->d[div_n-2]; /* pointer to the 'top' of snum */ wnump= &(snum->d[num_n-1]); /* Setup to 'res' */ res->neg= (num->neg^divisor->neg); if (!bn_wexpand(res,(loop+1))) goto err; res->top=loop; resp= &(res->d[loop-1]); /* space for temp */ if (!bn_wexpand(tmp,(div_n+1))) goto err; if (BN_ucmp(&wnum,sdiv) >= 0) { if (!BN_usub(&wnum,&wnum,sdiv)) goto err; *resp=1; res->d[res->top-1]=1; } else res->top--; resp--; for (i=0; i<loop-1; i++) { BN_ULONG q,l0; #ifdef BN_DIV3W q=bn_div_3_words(wnump,d1,d0); #else BN_ULONG n0,n1,rem=0; n0=wnump[0]; n1=wnump[-1]; if (n0 == d0) q=BN_MASK2; else /* n0 < d0 */ { #ifdef BN_LLONG BN_ULLONG t2; #if defined(BN_LLONG) && defined(BN_DIV2W) && !defined(bn_div_words) q=(BN_ULONG)(((((BN_ULLONG)n0)<<BN_BITS2)|n1)/d0); #else q=bn_div_words(n0,n1,d0); #endif #ifndef REMAINDER_IS_ALREADY_CALCULATED /* * rem doesn't have to be BN_ULLONG. The least we * know it's less that d0, isn't it? */ rem=(n1-q*d0)&BN_MASK2; #endif t2=(BN_ULLONG)d1*q; for (;;) { if (t2 <= ((((BN_ULLONG)rem)<<BN_BITS2)|wnump[-2])) break; q--; rem += d0; if (rem < d0) break; /* don't let rem overflow */ t2 -= d1; } #else /* !BN_LLONG */ BN_ULONG t2l,t2h,ql,qh; q=bn_div_words(n0,n1,d0); #ifndef REMAINDER_IS_ALREADY_CALCULATED rem=(n1-q*d0)&BN_MASK2; #endif #ifdef BN_UMULT_HIGH t2l = d1 * q; t2h = BN_UMULT_HIGH(d1,q); #else t2l=LBITS(d1); t2h=HBITS(d1); ql =LBITS(q); qh =HBITS(q); mul64(t2l,t2h,ql,qh); /* t2=(BN_ULLONG)d1*q; */ #endif for (;;) { if ((t2h < rem) || ((t2h == rem) && (t2l <= wnump[-2]))) break; q--; rem += d0; if (rem < d0) break; /* don't let rem overflow */ if (t2l < d1) t2h--; t2l -= d1; } #endif /* !BN_LLONG */ } #endif /* !BN_DIV3W */ l0=bn_mul_words(tmp->d,sdiv->d,div_n,q); wnum.d--; wnum.top++; tmp->d[div_n]=l0; for (j=div_n+1; j>0; j--) if (tmp->d[j-1]) break; tmp->top=j; j=wnum.top; BN_sub(&wnum,&wnum,tmp); snum->top=snum->top+wnum.top-j; if (wnum.neg) { q--; j=wnum.top; BN_add(&wnum,&wnum,sdiv); snum->top+=wnum.top-j; } *(resp--)=q; wnump--; } if (rm != NULL) { BN_rshift(rm,snum,norm_shift); rm->neg=num->neg; } BN_CTX_end(ctx); return(1); err: BN_CTX_end(ctx); return(0); } #endif /* rem != m */ int BN_mod(BIGNUM *rem, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx) { #if 0 /* The old slow way */ int i,nm,nd; BIGNUM *dv; if (BN_ucmp(m,d) < 0) return((BN_copy(rem,m) == NULL)?0:1); BN_CTX_start(ctx); dv=BN_CTX_get(ctx); if (!BN_copy(rem,m)) goto err; nm=BN_num_bits(rem); nd=BN_num_bits(d); if (!BN_lshift(dv,d,nm-nd)) goto err; for (i=nm-nd; i>=0; i--) { if (BN_cmp(rem,dv) >= 0) { if (!BN_sub(rem,rem,dv)) goto err; } if (!BN_rshift1(dv,dv)) goto err; } BN_CTX_end(ctx); return(1); err: BN_CTX_end(ctx); return(0); #else return(BN_div(NULL,rem,m,d,ctx)); #endif }