Commit 380e145d authored by Ulf Möller's avatar Ulf Möller
Browse files

Add "dif" variable to clean up the loop implementations. 

Submitted by: Nils Larsch
parent a9f2330f

crypto/bn/bn_add.c

+46 −45
Original line number Diff line number Diff line
@@ -64,7 +64,7 @@ 
int BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)

	{

	const BIGNUM *tmp;

	int a_neg = a->neg;

	int a_neg = a->neg, ret;



	bn_check_top(a);

	bn_check_top(b);
@@ -95,21 +95,17 @@ int BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) 
		return(1);

		}



	if (!BN_uadd(r,a,b)) return(0);

	if (a_neg) /* both are neg */

		r->neg=1;

	else

		r->neg=0;

	ret = BN_uadd(r,a,b);

	r->neg = a_neg;

	bn_check_top(r);

	return(1);

	return ret;

	}



/* unsigned add of b to a, r must be large enough */

/* unsigned add of b to a */

int BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)

	{

	register int i;

	int max,min;

	BN_ULONG *ap,*bp,*rp,carry,t1;

	int max,min,dif;

	BN_ULONG *ap,*bp,*rp,carry,t1,t2;

	const BIGNUM *tmp;



	bn_check_top(a);
@@ -119,9 +115,10 @@ int BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) 
		{ tmp=a; a=b; b=tmp; }

	max = a->top;

	min = b->top;

	dif = max - min;



	if (bn_wexpand(r,max+1) == NULL)

		return(0);

		return 0;



	r->top=max;
@@ -129,47 +126,46 @@ int BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) 
	ap=a->d;

	bp=b->d;

	rp=r->d;

	carry=0;



	carry=bn_add_words(rp,ap,bp,min);

	rp+=min;

	ap+=min;

	bp+=min;

	i=min;



	if (carry)

		{

		while (i < max)

		while (dif)

			{

			i++;

			dif--;

			t1 = *(ap++);

			if ((*(rp++)=(t1+1)&BN_MASK2) >= t1)

			t2 = (t1+1) & BN_MASK2;

			*(rp++) = t2;

			if (t2)

				{

				carry=0;

				break;

				}

			}

		if ((i >= max) && carry)

		if (carry)

			{

			*(rp++)=1;

			/* carry != 0 => dif == 0 */

			*rp = 1;

			r->top++;

			}

		}

	if (rp != ap)

		{

		for (; i<max; i++)

	if (dif && rp != ap)

		while (dif--)

			/* copy remaining words if ap != rp */

			*(rp++) = *(ap++);

		}

	/* memcpy(rp,ap,sizeof(*ap)*(max-i));*/

	r->neg = 0;

	bn_check_top(r);

	return(1);

	return 1;

	}



/* unsigned subtraction of b from a, a must be larger than b. */

int BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)

	{

	int max,min;

	int max,min,dif;

	register BN_ULONG t1,t2,*ap,*bp,*rp;

	int i,carry;

#if defined(IRIX_CC_BUG) && !defined(LINT)
@@ -179,14 +175,16 @@ int BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) 
	bn_check_top(a);

	bn_check_top(b);



	if (a->top < b->top) /* hmm... should not be happening */

	max = a->top;

	min = b->top;

	dif = max - min;



	if (dif < 0)	/* hmm... should not be happening */

		{

		BNerr(BN_F_BN_USUB,BN_R_ARG2_LT_ARG3);

		return(0);

		}



	max=a->top;

	min=b->top;

	if (bn_wexpand(r,max) == NULL) return(0);



	ap=a->d;
@@ -195,7 +193,7 @@ int BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) 


#if 1

	carry=0;

	for (i=0; i<min; i++)

	for (i = min; i != 0; i--)

		{

		t1= *(ap++);

		t2= *(bp++);
@@ -219,17 +217,20 @@ int BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) 
	ap+=min;

	bp+=min;

	rp+=min;

	i=min;

#endif

	if (carry) /* subtracted */

		{

		while (i < max)

		if (!dif)

			/* error: a < b */

			return 0;

		while (dif)

			{

			i++;

			dif--;

			t1 = *(ap++);

			t2 = (t1-1)&BN_MASK2;

			*(rp++) = t2;

			if (t1 > t2) break;

			if (t1)

				break;

			}

		}

#if 0
@@ -239,13 +240,13 @@ int BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) 
		{

		for (;;)

			{

			if (i++ >= max) break;

			if (!dif--) break;

			rp[0]=ap[0];

			if (i++ >= max) break;

			if (!dif--) break;

			rp[1]=ap[1];

			if (i++ >= max) break;

			if (!dif--) break;

			rp[2]=ap[2];

			if (i++ >= max) break;

			if (!dif--) break;

			rp[3]=ap[3];

			rp+=4;

			ap+=4;