[thirdparty/openssl.git] / crypto / bn / bn_div.c

/* 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
#  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)
 *     rm->neg == num->neg                 (unless the remainder is zero)
 * 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,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);
	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;
	tmp->neg=0;

	/* 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 */
	BN_init(&wnum);
	wnum.d=	 &(snum->d[loop]);
	wnum.top= div_n;
	wnum.dmax= snum->dmax+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--;
	if (res->top == 0)
		res->neg = 0;
	resp--;

	for (i=0; i<loop-1; i++)
		{
		BN_ULONG q,l0;
#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);
#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;
		if (!BN_sub(&wnum,&wnum,tmp)) goto err;

		snum->top=snum->top+wnum.top-j;

		if (wnum.neg)
			{
			q--;
			j=wnum.top;
			if (!BN_add(&wnum,&wnum,sdiv)) goto err;
			snum->top+=wnum.top-j;
			}
		*(resp--)=q;
		wnump--;
		}
	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_CTX_end(ctx);
	return(1);
err:
	BN_CTX_end(ctx);
	return(0);
	}

#endif
Commit	Line	Data
d02b48c6	1	/* crypto/bn/bn_div.c */
58964a49	2	/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
d02b48c6 RE	3	* All rights reserved.
	4	*
	5	* This package is an SSL implementation written
	6	* by Eric Young (eay@cryptsoft.com).
	7	* The implementation was written so as to conform with Netscapes SSL.
	8	*
	9	* This library is free for commercial and non-commercial use as long as
	10	* the following conditions are aheared to. The following conditions
	11	* apply to all code found in this distribution, be it the RC4, RSA,
	12	* lhash, DES, etc., code; not just the SSL code. The SSL documentation
	13	* included with this distribution is covered by the same copyright terms
	14	* except that the holder is Tim Hudson (tjh@cryptsoft.com).
	15	*
	16	* Copyright remains Eric Young's, and as such any Copyright notices in
	17	* the code are not to be removed.
	18	* If this package is used in a product, Eric Young should be given attribution
	19	* as the author of the parts of the library used.
	20	* This can be in the form of a textual message at program startup or
	21	* in documentation (online or textual) provided with the package.
	22	*
	23	* Redistribution and use in source and binary forms, with or without
	24	* modification, are permitted provided that the following conditions
	25	* are met:
	26	* 1. Redistributions of source code must retain the copyright
	27	* notice, this list of conditions and the following disclaimer.
	28	* 2. Redistributions in binary form must reproduce the above copyright
	29	* notice, this list of conditions and the following disclaimer in the
	30	* documentation and/or other materials provided with the distribution.
	31	* 3. All advertising materials mentioning features or use of this software
	32	* must display the following acknowledgement:
	33	* "This product includes cryptographic software written by
	34	* Eric Young (eay@cryptsoft.com)"
	35	* The word 'cryptographic' can be left out if the rouines from the library
	36	* being used are not cryptographic related :-).
	37	* 4. If you include any Windows specific code (or a derivative thereof) from
	38	* the apps directory (application code) you must include an acknowledgement:
	39	* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
	40	*
	41	* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
	42	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	43	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	44	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	45	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	46	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	47	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	48	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	49	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	50	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	51	* SUCH DAMAGE.
	52	*
	53	* The licence and distribution terms for any publically available version or
	54	* derivative of this code cannot be changed. i.e. this code cannot simply be
	55	* copied and put under another distribution licence
	56	* [including the GNU Public Licence.]
	57	*/
	58
	59	#include <stdio.h>
84c15db5	60	#include <openssl/bn.h>
d02b48c6 RE	61	#include "cryptlib.h"
	62	#include "bn_lcl.h"
	63
78a0c1f1	64
d02b48c6	65	/* The old slow way */
4a6222d7	66	#if 0
0bde1089 UM	67	int BN_div(BIGNUM dv, BIGNUM rem, const BIGNUM m, const BIGNUM d,
0bde1089 UM	68	BN_CTX *ctx)
d02b48c6 RE	69	{
d02b48c6 RE	70	int i,nm,nd;
9b141126	71	int ret = 0;
d02b48c6 RE	72	BIGNUM *D;
d02b48c6 RE	73
dfeab068 RE	74	bn_check_top(m);
dfeab068 RE	75	bn_check_top(d);
d02b48c6 RE	76	if (BN_is_zero(d))
	77	{
	78	BNerr(BN_F_BN_DIV,BN_R_DIV_BY_ZERO);
	79	return(0);
	80	}
	81
	82	if (BN_ucmp(m,d) < 0)
	83	{
	84	if (rem != NULL)
	85	{ if (BN_copy(rem,m) == NULL) return(0); }
	86	if (dv != NULL) BN_zero(dv);
	87	return(1);
	88	}
	89
9b141126 UM	90	BN_CTX_start(ctx);
	91	D = BN_CTX_get(ctx);
	92	if (dv == NULL) dv = BN_CTX_get(ctx);
	93	if (rem == NULL) rem = BN_CTX_get(ctx);
	94	if (D == NULL \|\| dv == NULL \|\| rem == NULL)
	95	goto end;
d02b48c6 RE	96
	97	nd=BN_num_bits(d);
	98	nm=BN_num_bits(m);
9b141126 UM	99	if (BN_copy(D,d) == NULL) goto end;
9b141126 UM	100	if (BN_copy(rem,m) == NULL) goto end;
d02b48c6 RE	101
	102	/* The next 2 are needed so we can do a dv->d[0]\|=1 later
	103	* since BN_lshift1 will only work once there is a value :-) */
	104	BN_zero(dv);
dfeab068	105	bn_wexpand(dv,1);
d02b48c6 RE	106	dv->top=1;
d02b48c6 RE	107
9b141126	108	if (!BN_lshift(D,D,nm-nd)) goto end;
d02b48c6 RE	109	for (i=nm-nd; i>=0; i--)
d02b48c6 RE	110	{
9b141126	111	if (!BN_lshift1(dv,dv)) goto end;
d02b48c6 RE	112	if (BN_ucmp(rem,D) >= 0)
	113	{
	114	dv->d[0]\|=1;
9b141126	115	if (!BN_usub(rem,rem,D)) goto end;
d02b48c6 RE	116	}
d02b48c6 RE	117	/* CAN IMPROVE (and have now :=) */
9b141126	118	if (!BN_rshift1(D,D)) goto end;
d02b48c6 RE	119	}
	120	rem->neg=BN_is_zero(rem)?0:m->neg;
	121	dv->neg=m->neg^d->neg;
9b141126 UM	122	ret = 1;
	123	end:
	124	BN_CTX_end(ctx);
	125	return(ret);
d02b48c6 RE	126	}
	127
	128	#else
	129
cf1b7d96 RL	130	#if !defined(OPENSSL_NO_ASM) && !defined(OPENSSL_NO_INLINE_ASM) \
cf1b7d96 RL	131	&& !defined(PEDANTIC) && !defined(BN_DIV3W)
4a6222d7	132	# if defined(__GNUC__) && __GNUC__>=2
5dd955dc	133	# if defined(__i386) \|\| defined (__i386__)
4a6222d7 UM	134	/*
	135	* There were two reasons for implementing this template:
	136	* - GNU C generates a call to a function (__udivdi3 to be exact)
	137	* in reply to ((((BN_ULLONG)n0)<<BN_BITS2)\|n1)/d0 (I fail to
	138	* understand why...);
	139	* - divl doesn't only calculate quotient, but also leaves
	140	* remainder in %edx which we can definitely use here:-)
	141	*
	142	* <appro@fy.chalmers.se>
	143	*/
	144	# define bn_div_words(n0,n1,d0) \
	145	({ asm volatile ( \
	146	"divl %4" \
	147	: "=a"(q), "=d"(rem) \
	148	: "a"(n1), "d"(n0), "g"(d0) \
	149	: "cc"); \
	150	q; \
	151	})
	152	# define REMAINDER_IS_ALREADY_CALCULATED
	153	# endif /* __<cpu> */
	154	# endif /* __GNUC__ */
cf1b7d96	155	#endif /* OPENSSL_NO_ASM */
4a6222d7	156
78a0c1f1 BM	157
	158	/* BN_div computes dv := num / divisor, rounding towards zero, and sets up
	159	* rm such that dv*divisor + rm = num holds.
	160	* Thus:
	161	* dv->neg == num->neg ^ divisor->neg (unless the result is zero)
	162	* rm->neg == num->neg (unless the remainder is zero)
	163	* If 'dv' or 'rm' is NULL, the respective value is not returned.
	164	*/
84c15db5 BL	165	int BN_div(BIGNUM dv, BIGNUM rm, const BIGNUM num, const BIGNUM divisor,
84c15db5 BL	166	BN_CTX *ctx)
d02b48c6 RE	167	{
	168	int norm_shift,i,j,loop;
	169	BIGNUM tmp,wnum,snum,sdiv,res;
	170	BN_ULONG resp,wnump;
	171	BN_ULONG d0,d1;
	172	int num_n,div_n;
	173
dfeab068 RE	174	bn_check_top(num);
	175	bn_check_top(divisor);
	176
58964a49	177	if (BN_is_zero(divisor))
d02b48c6 RE	178	{
	179	BNerr(BN_F_BN_DIV,BN_R_DIV_BY_ZERO);
	180	return(0);
	181	}
	182
	183	if (BN_ucmp(num,divisor) < 0)
	184	{
	185	if (rm != NULL)
	186	{ if (BN_copy(rm,num) == NULL) return(0); }
	187	if (dv != NULL) BN_zero(dv);
	188	return(1);
	189	}
	190
9b141126 UM	191	BN_CTX_start(ctx);
9b141126 UM	192	tmp=BN_CTX_get(ctx);
9b141126 UM	193	snum=BN_CTX_get(ctx);
9b141126 UM	194	sdiv=BN_CTX_get(ctx);
d02b48c6	195	if (dv == NULL)
9b141126	196	res=BN_CTX_get(ctx);
d02b48c6	197	else res=dv;
7f7b8d68 BM	198	if (sdiv == NULL \|\| res == NULL) goto err;
7f7b8d68 BM	199	tmp->neg=0;
d02b48c6 RE	200
	201	/* First we normalise the numbers */
	202	norm_shift=BN_BITS2-((BN_num_bits(divisor))%BN_BITS2);
9cdf87f1	203	if (!(BN_lshift(sdiv,divisor,norm_shift))) goto err;
d02b48c6 RE	204	sdiv->neg=0;
d02b48c6 RE	205	norm_shift+=BN_BITS2;
9cdf87f1	206	if (!(BN_lshift(snum,num,norm_shift))) goto err;
d02b48c6 RE	207	snum->neg=0;
	208	div_n=sdiv->top;
	209	num_n=snum->top;
	210	loop=num_n-div_n;
	211
	212	/* Lets setup a 'window' into snum
	213	* This is the part that corresponds to the current
	214	* 'area' being divided */
dfeab068	215	BN_init(&wnum);
d02b48c6 RE	216	wnum.d= &(snum->d[loop]);
d02b48c6 RE	217	wnum.top= div_n;
2d978cbd	218	wnum.dmax= snum->dmax+1; /* a bit of a lie */
d02b48c6 RE	219
	220	/* Get the top 2 words of sdiv */
	221	/* i=sdiv->top; */
	222	d0=sdiv->d[div_n-1];
	223	d1=(div_n == 1)?0:sdiv->d[div_n-2];
	224
	225	/* pointer to the 'top' of snum */
	226	wnump= &(snum->d[num_n-1]);
	227
	228	/* Setup to 'res' */
	229	res->neg= (num->neg^divisor->neg);
58964a49	230	if (!bn_wexpand(res,(loop+1))) goto err;
dfeab068	231	res->top=loop;
d02b48c6 RE	232	resp= &(res->d[loop-1]);
	233
	234	/* space for temp */
58964a49	235	if (!bn_wexpand(tmp,(div_n+1))) goto err;
d02b48c6 RE	236
	237	if (BN_ucmp(&wnum,sdiv) >= 0)
	238	{
dfeab068	239	if (!BN_usub(&wnum,&wnum,sdiv)) goto err;
d02b48c6 RE	240	*resp=1;
	241	res->d[res->top-1]=1;
	242	}
	243	else
	244	res->top--;
80d89e6a BM	245	if (res->top == 0)
80d89e6a BM	246	res->neg = 0;
d02b48c6 RE	247	resp--;
	248
	249	for (i=0; i<loop-1; i++)
	250	{
0dd25e36	251	BN_ULONG q,l0;
cf1b7d96	252	#if defined(BN_DIV3W) && !defined(OPENSSL_NO_ASM)
500230ee	253	BN_ULONG bn_div_3_words(BN_ULONG*,BN_ULONG,BN_ULONG);
0bbd0352	254	q=bn_div_3_words(wnump,d1,d0);
0dd25e36	255	#else
4c22909e	256	BN_ULONG n0,n1,rem=0;
d02b48c6	257
d02b48c6 RE	258	n0=wnump[0];
	259	n1=wnump[-1];
	260	if (n0 == d0)
	261	q=BN_MASK2;
4a6222d7 UM	262	else /* n0 < d0 */
	263	{
	264	#ifdef BN_LLONG
	265	BN_ULLONG t2;
	266
4c22909e	267	#if defined(BN_LLONG) && defined(BN_DIV2W) && !defined(bn_div_words)
8e1589ec	268	q=(BN_ULONG)(((((BN_ULLONG)n0)<<BN_BITS2)\|n1)/d0);
0dd25e36	269	#else
dfeab068	270	q=bn_div_words(n0,n1,d0);
0dd25e36	271	#endif
0dd25e36	272
fe7cd164	273	#ifndef REMAINDER_IS_ALREADY_CALCULATED
4a6222d7 UM	274	/*
	275	* rem doesn't have to be BN_ULLONG. The least we
	276	* know it's less that d0, isn't it?
	277	*/
	278	rem=(n1-q*d0)&BN_MASK2;
4c22909e	279	#endif
4a6222d7 UM	280	t2=(BN_ULLONG)d1*q;
	281
	282	for (;;)
	283	{
	284	if (t2 <= ((((BN_ULLONG)rem)<<BN_BITS2)\|wnump[-2]))
	285	break;
	286	q--;
	287	rem += d0;
	288	if (rem < d0) break; /* don't let rem overflow */
	289	t2 -= d1;
	290	}
	291	#else /* !BN_LLONG */
	292	BN_ULONG t2l,t2h,ql,qh;
0dd25e36	293
4a6222d7	294	q=bn_div_words(n0,n1,d0);
fe7cd164	295	#ifndef REMAINDER_IS_ALREADY_CALCULATED
4a6222d7	296	rem=(n1-q*d0)&BN_MASK2;
4c22909e	297	#endif
4a6222d7	298
fb81ac5e	299	#ifdef BN_UMULT_HIGH
4a6222d7 UM	300	t2l = d1 * q;
4a6222d7 UM	301	t2h = BN_UMULT_HIGH(d1,q);
fb81ac5e	302	#else
4a6222d7 UM	303	t2l=LBITS(d1); t2h=HBITS(d1);
	304	ql =LBITS(q); qh =HBITS(q);
	305	mul64(t2l,t2h,ql,qh); /* t2=(BN_ULLONG)d1q; /
fb81ac5e	306	#endif
0dd25e36	307
4a6222d7 UM	308	for (;;)
	309	{
	310	if ((t2h < rem) \|\|
	311	((t2h == rem) && (t2l <= wnump[-2])))
	312	break;
	313	q--;
	314	rem += d0;
	315	if (rem < d0) break; /* don't let rem overflow */
	316	if (t2l < d1) t2h--; t2l -= d1;
	317	}
	318	#endif /* !BN_LLONG */
d02b48c6	319	}
4c22909e	320	#endif /* !BN_DIV3W */
4a6222d7	321
58964a49	322	l0=bn_mul_words(tmp->d,sdiv->d,div_n,q);
0bbd0352	323	wnum.d--; wnum.top++;
d02b48c6 RE	324	tmp->d[div_n]=l0;
	325	for (j=div_n+1; j>0; j--)
	326	if (tmp->d[j-1]) break;
	327	tmp->top=j;
	328
	329	j=wnum.top;
9cdf87f1	330	if (!BN_sub(&wnum,&wnum,tmp)) goto err;
d02b48c6 RE	331
	332	snum->top=snum->top+wnum.top-j;
	333
	334	if (wnum.neg)
	335	{
	336	q--;
	337	j=wnum.top;
9cdf87f1	338	if (!BN_add(&wnum,&wnum,sdiv)) goto err;
d02b48c6 RE	339	snum->top+=wnum.top-j;
	340	}
	341	*(resp--)=q;
	342	wnump--;
	343	}
	344	if (rm != NULL)
	345	{
3d2e469c DSH	346	/* Keep a copy of the neg flag in num because if rm==num
	347	* BN_rshift() will overwrite it.
	348	*/
	349	int neg = num->neg;
d02b48c6	350	BN_rshift(rm,snum,norm_shift);
78a0c1f1	351	if (!BN_is_zero(rm))
3d2e469c	352	rm->neg = neg;
d02b48c6	353	}
9b141126	354	BN_CTX_end(ctx);
d02b48c6 RE	355	return(1);
d02b48c6 RE	356	err:
4a6222d7	357	BN_CTX_end(ctx);
d02b48c6 RE	358	return(0);
	359	}
	360
	361	#endif