Initial import

1 files changed, 650 insertions, 0 deletions

diff --git a/openssl/crypto/bn/bn_div.c b/openssl/crypto/bn/bn_div.c
new file mode 100644
index 00000000..802a43d6
--- /dev/null
+++ b/openssl/crypto/bn/bn_div.c
@@ -0,0 +1,650 @@
+/* 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);
+	if(bn_wexpand(dv,1) == NULL) goto end;
+	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 || tmp == NULL || snum == 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;
+
+			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
+			{
+			BN_ULONG ql, qh;
+			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;
+
+			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
+			{
+			BN_ULONG ql, qh;
+			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