diff options
author | marha <marha@users.sourceforge.net> | 2009-06-28 22:07:26 +0000 |
---|---|---|
committer | marha <marha@users.sourceforge.net> | 2009-06-28 22:07:26 +0000 |
commit | 3562e78743202e43aec8727005182a2558117eca (patch) | |
tree | 8f9113a77d12470c5c851a2a8e4cb02e89df7d43 /openssl/crypto/bn/bn_div.c | |
download | vcxsrv-3562e78743202e43aec8727005182a2558117eca.tar.gz vcxsrv-3562e78743202e43aec8727005182a2558117eca.tar.bz2 vcxsrv-3562e78743202e43aec8727005182a2558117eca.zip |
Checked in the following released items:
xkeyboard-config-1.4.tar.gz
ttf-bitstream-vera-1.10.tar.gz
font-alias-1.0.1.tar.gz
font-sun-misc-1.0.0.tar.gz
font-sun-misc-1.0.0.tar.gz
font-sony-misc-1.0.0.tar.gz
font-schumacher-misc-1.0.0.tar.gz
font-mutt-misc-1.0.0.tar.gz
font-misc-misc-1.0.0.tar.gz
font-misc-meltho-1.0.0.tar.gz
font-micro-misc-1.0.0.tar.gz
font-jis-misc-1.0.0.tar.gz
font-isas-misc-1.0.0.tar.gz
font-dec-misc-1.0.0.tar.gz
font-daewoo-misc-1.0.0.tar.gz
font-cursor-misc-1.0.0.tar.gz
font-arabic-misc-1.0.0.tar.gz
font-winitzki-cyrillic-1.0.0.tar.gz
font-misc-cyrillic-1.0.0.tar.gz
font-cronyx-cyrillic-1.0.0.tar.gz
font-screen-cyrillic-1.0.1.tar.gz
font-xfree86-type1-1.0.1.tar.gz
font-adobe-utopia-type1-1.0.1.tar.gz
font-ibm-type1-1.0.0.tar.gz
font-bitstream-type1-1.0.0.tar.gz
font-bitstream-speedo-1.0.0.tar.gz
font-bh-ttf-1.0.0.tar.gz
font-bh-type1-1.0.0.tar.gz
font-bitstream-100dpi-1.0.0.tar.gz
font-bh-lucidatypewriter-100dpi-1.0.0.tar.gz
font-bh-100dpi-1.0.0.tar.gz
font-adobe-utopia-100dpi-1.0.1.tar.gz
font-adobe-100dpi-1.0.0.tar.gz
font-util-1.0.1.tar.gz
font-bitstream-75dpi-1.0.0.tar.gz
font-bh-lucidatypewriter-75dpi-1.0.0.tar.gz
font-adobe-utopia-75dpi-1.0.1.tar.gz
font-bh-75dpi-1.0.0.tar.gz
bdftopcf-1.0.1.tar.gz
font-adobe-75dpi-1.0.0.tar.gz
mkfontscale-1.0.6.tar.gz
openssl-0.9.8k.tar.gz
bigreqsproto-1.0.2.tar.gz
xtrans-1.2.2.tar.gz
resourceproto-1.0.2.tar.gz
inputproto-1.4.4.tar.gz
compositeproto-0.4.tar.gz
damageproto-1.1.0.tar.gz
zlib-1.2.3.tar.gz
xkbcomp-1.0.5.tar.gz
freetype-2.3.9.tar.gz
pthreads-w32-2-8-0-release.tar.gz
pixman-0.12.0.tar.gz
kbproto-1.0.3.tar.gz
evieext-1.0.2.tar.gz
fixesproto-4.0.tar.gz
recordproto-1.13.2.tar.gz
randrproto-1.2.2.tar.gz
scrnsaverproto-1.1.0.tar.gz
renderproto-0.9.3.tar.gz
xcmiscproto-1.1.2.tar.gz
fontsproto-2.0.2.tar.gz
xextproto-7.0.3.tar.gz
xproto-7.0.14.tar.gz
libXdmcp-1.0.2.tar.gz
libxkbfile-1.0.5.tar.gz
libfontenc-1.0.4.tar.gz
libXfont-1.3.4.tar.gz
libX11-1.1.5.tar.gz
libXau-1.0.4.tar.gz
libxcb-1.1.tar.gz
xorg-server-1.5.3.tar.gz
Diffstat (limited to 'openssl/crypto/bn/bn_div.c')
-rw-r--r-- | openssl/crypto/bn/bn_div.c | 643 |
1 files changed, 643 insertions, 0 deletions
diff --git a/openssl/crypto/bn/bn_div.c b/openssl/crypto/bn/bn_div.c new file mode 100644 index 000000000..1e8e57626 --- /dev/null +++ b/openssl/crypto/bn/bn_div.c @@ -0,0 +1,643 @@ +/* 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(OPENSSL_NO_ASM) && !defined(OPENSSL_NO_INLINE_ASM) \ + && !defined(PEDANTIC) && !defined(BN_DIV3W) +# if defined(__GNUC__) && __GNUC__>=2 +# if defined(__i386) || 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 +# elif defined(__x86_64) && defined(SIXTY_FOUR_BIT_LONG) + /* + * Same story here, but it's 128-bit by 64-bit division. Wow! + * <appro@fy.chalmers.se> + */ +# define bn_div_words(n0,n1,d0) \ + ({ asm volatile ( \ + "divq %4" \ + : "=a"(q), "=d"(rem) \ + : "a"(n1), "d"(n0), "g"(d0) \ + : "cc"); \ + q; \ + }) +# define REMAINDER_IS_ALREADY_CALCULATED +# endif /* __<cpu> */ +# endif /* __GNUC__ */ +#endif /* OPENSSL_NO_ASM */ + + +/* BN_div[_no_branch] computes dv := num / divisor, rounding towards + * zero, and sets up rm such that dv*divisor + rm = num holds. + * Thus: + * dv->neg == num->neg ^ divisor->neg (unless the result is zero) + * rm->neg == num->neg (unless the remainder is zero) + * If 'dv' or 'rm' is NULL, the respective value is not returned. + */ +static int BN_div_no_branch(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, + const BIGNUM *divisor, BN_CTX *ctx); +int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor, + BN_CTX *ctx) + { + int norm_shift,i,loop; + BIGNUM *tmp,wnum,*snum,*sdiv,*res; + BN_ULONG *resp,*wnump; + BN_ULONG d0,d1; + int num_n,div_n; + + /* Invalid zero-padding would have particularly bad consequences + * in the case of 'num', so don't just rely on bn_check_top() for this one + * (bn_check_top() works only for BN_DEBUG builds) */ + if (num->top > 0 && num->d[num->top - 1] == 0) + { + BNerr(BN_F_BN_DIV,BN_R_NOT_INITIALIZED); + return 0; + } + + bn_check_top(num); + + if ((BN_get_flags(num, BN_FLG_CONSTTIME) != 0) || (BN_get_flags(divisor, BN_FLG_CONSTTIME) != 0)) + { + return BN_div_no_branch(dv, rm, num, divisor, ctx); + } + + bn_check_top(dv); + bn_check_top(rm); + /* bn_check_top(num); */ /* 'num' has been checked already */ + 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); + snum=BN_CTX_get(ctx); + sdiv=BN_CTX_get(ctx); + if (dv == NULL) + res=BN_CTX_get(ctx); + else res=dv; + if (sdiv == NULL || res == NULL) goto err; + + /* First we normalise the numbers */ + norm_shift=BN_BITS2-((BN_num_bits(divisor))%BN_BITS2); + if (!(BN_lshift(sdiv,divisor,norm_shift))) goto err; + sdiv->neg=0; + norm_shift+=BN_BITS2; + if (!(BN_lshift(snum,num,norm_shift))) goto err; + 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 */ + wnum.neg = 0; + wnum.d = &(snum->d[loop]); + wnum.top = div_n; + /* only needed when BN_ucmp messes up the values between top and max */ + wnum.dmax = snum->dmax - loop; /* so we don't step out of bounds */ + + /* Get the top 2 words of sdiv */ + /* div_n=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_DEBUG_RAND is defined BN_ucmp changes (via + * bn_pollute) the const bignum arguments => + * clean the values between top and max again */ + bn_clear_top2max(&wnum); + bn_sub_words(wnum.d, wnum.d, sdiv->d, div_n); + *resp=1; + } + else + res->top--; + /* if res->top == 0 then clear the neg value otherwise decrease + * the resp pointer */ + if (res->top == 0) + res->neg = 0; + else + resp--; + + for (i=0; i<loop-1; i++, wnump--, resp--) + { + BN_ULONG q,l0; + /* the first part of the loop uses the top two words of + * snum and sdiv to calculate a BN_ULONG q such that + * | wnum - sdiv * q | < sdiv */ +#if defined(BN_DIV3W) && !defined(OPENSSL_NO_ASM) + BN_ULONG bn_div_3_words(BN_ULONG*,BN_ULONG,BN_ULONG); + 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); +#ifdef BN_DEBUG_LEVITTE + fprintf(stderr,"DEBUG: bn_div_words(0x%08X,0x%08X,0x%08\ +X) -> 0x%08X\n", + n0, n1, d0, q); +#endif +#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); +#ifdef BN_DEBUG_LEVITTE + fprintf(stderr,"DEBUG: bn_div_words(0x%08X,0x%08X,0x%08\ +X) -> 0x%08X\n", + n0, n1, d0, q); +#endif +#ifndef REMAINDER_IS_ALREADY_CALCULATED + rem=(n1-q*d0)&BN_MASK2; +#endif + +#if defined(BN_UMULT_LOHI) + BN_UMULT_LOHI(t2l,t2h,d1,q); +#elif defined(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); + tmp->d[div_n]=l0; + wnum.d--; + /* ingore top values of the bignums just sub the two + * BN_ULONG arrays with bn_sub_words */ + if (bn_sub_words(wnum.d, wnum.d, tmp->d, div_n+1)) + { + /* Note: As we have considered only the leading + * two BN_ULONGs in the calculation of q, sdiv * q + * might be greater than wnum (but then (q-1) * sdiv + * is less or equal than wnum) + */ + q--; + if (bn_add_words(wnum.d, wnum.d, sdiv->d, div_n)) + /* we can't have an overflow here (assuming + * that q != 0, but if q == 0 then tmp is + * zero anyway) */ + (*wnump)++; + } + /* store part of the result */ + *resp = q; + } + bn_correct_top(snum); + if (rm != NULL) + { + /* Keep a copy of the neg flag in num because if rm==num + * BN_rshift() will overwrite it. + */ + int neg = num->neg; + BN_rshift(rm,snum,norm_shift); + if (!BN_is_zero(rm)) + rm->neg = neg; + bn_check_top(rm); + } + BN_CTX_end(ctx); + return(1); +err: + bn_check_top(rm); + BN_CTX_end(ctx); + return(0); + } + + +/* BN_div_no_branch is a special version of BN_div. It does not contain + * branches that may leak sensitive information. + */ +static int BN_div_no_branch(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, + const BIGNUM *divisor, BN_CTX *ctx) + { + int norm_shift,i,loop; + BIGNUM *tmp,wnum,*snum,*sdiv,*res; + BN_ULONG *resp,*wnump; + BN_ULONG d0,d1; + int num_n,div_n; + + bn_check_top(dv); + bn_check_top(rm); + /* bn_check_top(num); */ /* 'num' has been checked in BN_div() */ + bn_check_top(divisor); + + if (BN_is_zero(divisor)) + { + BNerr(BN_F_BN_DIV_NO_BRANCH,BN_R_DIV_BY_ZERO); + return(0); + } + + BN_CTX_start(ctx); + tmp=BN_CTX_get(ctx); + snum=BN_CTX_get(ctx); + sdiv=BN_CTX_get(ctx); + if (dv == NULL) + res=BN_CTX_get(ctx); + else res=dv; + if (sdiv == NULL || res == NULL) goto err; + + /* First we normalise the numbers */ + norm_shift=BN_BITS2-((BN_num_bits(divisor))%BN_BITS2); + if (!(BN_lshift(sdiv,divisor,norm_shift))) goto err; + sdiv->neg=0; + norm_shift+=BN_BITS2; + if (!(BN_lshift(snum,num,norm_shift))) goto err; + snum->neg=0; + + /* Since we don't know whether snum is larger than sdiv, + * we pad snum with enough zeroes without changing its + * value. + */ + if (snum->top <= sdiv->top+1) + { + if (bn_wexpand(snum, sdiv->top + 2) == NULL) goto err; + for (i = snum->top; i < sdiv->top + 2; i++) snum->d[i] = 0; + snum->top = sdiv->top + 2; + } + else + { + if (bn_wexpand(snum, snum->top + 1) == NULL) goto err; + snum->d[snum->top] = 0; + snum->top ++; + } + + 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 */ + wnum.neg = 0; + wnum.d = &(snum->d[loop]); + wnum.top = div_n; + /* only needed when BN_ucmp messes up the values between top and max */ + wnum.dmax = snum->dmax - loop; /* so we don't step out of bounds */ + + /* Get the top 2 words of sdiv */ + /* div_n=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-1; + resp= &(res->d[loop-1]); + + /* space for temp */ + if (!bn_wexpand(tmp,(div_n+1))) goto err; + + /* if res->top == 0 then clear the neg value otherwise decrease + * the resp pointer */ + if (res->top == 0) + res->neg = 0; + else + resp--; + + for (i=0; i<loop-1; i++, wnump--, resp--) + { + BN_ULONG q,l0; + /* the first part of the loop uses the top two words of + * snum and sdiv to calculate a BN_ULONG q such that + * | wnum - sdiv * q | < sdiv */ +#if defined(BN_DIV3W) && !defined(OPENSSL_NO_ASM) + BN_ULONG bn_div_3_words(BN_ULONG*,BN_ULONG,BN_ULONG); + 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); +#ifdef BN_DEBUG_LEVITTE + fprintf(stderr,"DEBUG: bn_div_words(0x%08X,0x%08X,0x%08\ +X) -> 0x%08X\n", + n0, n1, d0, q); +#endif +#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); +#ifdef BN_DEBUG_LEVITTE + fprintf(stderr,"DEBUG: bn_div_words(0x%08X,0x%08X,0x%08\ +X) -> 0x%08X\n", + n0, n1, d0, q); +#endif +#ifndef REMAINDER_IS_ALREADY_CALCULATED + rem=(n1-q*d0)&BN_MASK2; +#endif + +#if defined(BN_UMULT_LOHI) + BN_UMULT_LOHI(t2l,t2h,d1,q); +#elif defined(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); + tmp->d[div_n]=l0; + wnum.d--; + /* ingore top values of the bignums just sub the two + * BN_ULONG arrays with bn_sub_words */ + if (bn_sub_words(wnum.d, wnum.d, tmp->d, div_n+1)) + { + /* Note: As we have considered only the leading + * two BN_ULONGs in the calculation of q, sdiv * q + * might be greater than wnum (but then (q-1) * sdiv + * is less or equal than wnum) + */ + q--; + if (bn_add_words(wnum.d, wnum.d, sdiv->d, div_n)) + /* we can't have an overflow here (assuming + * that q != 0, but if q == 0 then tmp is + * zero anyway) */ + (*wnump)++; + } + /* store part of the result */ + *resp = q; + } + bn_correct_top(snum); + if (rm != NULL) + { + /* Keep a copy of the neg flag in num because if rm==num + * BN_rshift() will overwrite it. + */ + int neg = num->neg; + BN_rshift(rm,snum,norm_shift); + if (!BN_is_zero(rm)) + rm->neg = neg; + bn_check_top(rm); + } + bn_correct_top(res); + BN_CTX_end(ctx); + return(1); +err: + bn_check_top(rm); + BN_CTX_end(ctx); + return(0); + } + +#endif |