Upgraded to openssl-1.0.2

1 files changed, 392 insertions, 363 deletions

diff --git a/openssl/crypto/bn/bn_div.c b/openssl/crypto/bn/bn_div.c
index 7b2403185..72e6ce3f7 100644
--- a/openssl/crypto/bn/bn_div.c
+++ b/openssl/crypto/bn/bn_div.c
@@ -5,21 +5,21 @@
  * 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:
@@ -34,10 +34,10 @@
  *     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 
+ * 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
@@ -49,7 +49,7 @@
  * 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
@@ -61,77 +61,86 @@
 #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;
-			}
+           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;
+        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);
-	}
+    BN_CTX_end(ctx);
+    return (ret);
+}
 
 #else
 
-#if !defined(OPENSSL_NO_ASM) && !defined(OPENSSL_NO_INLINE_ASM) \
+# 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__)
-   /*
+#  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
@@ -139,39 +148,39 @@ int BN_div(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m, const BIGNUM *d,
     * - divl doesn't only calculate quotient, but also leaves
     *   remainder in %edx which we can definitely use here:-)
     *
-    *					<appro@fy.chalmers.se>
+    *                                   <appro@fy.chalmers.se>
     */
-#undef bn_div_words
-#  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)
+#    undef bn_div_words
+#    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>
+    *                                   <appro@fy.chalmers.se>
     */
-#  undef bn_div_words
-#  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 computes  dv := num / divisor,  rounding towards
+#    undef bn_div_words
+#    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 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)
@@ -179,270 +188,290 @@ int BN_div(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m, const BIGNUM *d,
  * If 'dv' or 'rm' is NULL, the respective value is not returned.
  */
 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;
-	int no_branch=0;
-
-	/* 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))
-		{
-		no_branch=1;
-		}
-
-	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 (!no_branch && 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;
-
-	if (no_branch)
-		{
-		/* 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-no_branch;
-	resp= &(res->d[loop-1]);
-
-	/* space for temp */
-	if (!bn_wexpand(tmp,(div_n+1))) goto err;
-
-	if (!no_branch)
-		{
-		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);
-		}
-	if (no_branch)	bn_correct_top(res);
-	BN_CTX_end(ctx);
-	return(1);
-err:
-	bn_check_top(rm);
-	BN_CTX_end(ctx);
-	return(0);
-	}
+           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;
+    int no_branch = 0;
+
+    /*
+     * Invalid zero-padding would have particularly bad consequences so don't
+     * just rely on bn_check_top() here (bn_check_top() works only for
+     * BN_DEBUG builds)
+     */
+    if ((num->top > 0 && num->d[num->top - 1] == 0) ||
+        (divisor->top > 0 && divisor->d[divisor->top - 1] == 0)) {
+        BNerr(BN_F_BN_DIV, BN_R_NOT_INITIALIZED);
+        return 0;
+    }
+
+    bn_check_top(num);
+    bn_check_top(divisor);
+
+    if ((BN_get_flags(num, BN_FLG_CONSTTIME) != 0)
+        || (BN_get_flags(divisor, BN_FLG_CONSTTIME) != 0)) {
+        no_branch = 1;
+    }
+
+    bn_check_top(dv);
+    bn_check_top(rm);
+    /*- bn_check_top(num); *//*
+     * 'num' has been checked already
+     */
+    /*- bn_check_top(divisor); *//*
+     * 'divisor' has been checked already
+     */
+
+    if (BN_is_zero(divisor)) {
+        BNerr(BN_F_BN_DIV, BN_R_DIV_BY_ZERO);
+        return (0);
+    }
+
+    if (!no_branch && 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;
+
+    if (no_branch) {
+        /*
+         * 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 - no_branch;
+    resp = &(res->d[loop - 1]);
+
+    /* space for temp */
+    if (!bn_wexpand(tmp, (div_n + 1)))
+        goto err;
+
+    if (!no_branch) {
+        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);
+    }
+    if (no_branch)
+        bn_correct_top(res);
+    BN_CTX_end(ctx);
+    return (1);
+ err:
+    bn_check_top(rm);
+    BN_CTX_end(ctx);
+    return (0);
+}
 #endif