mirror/openssl
2
0
Fork 0
mirror of https://github.com/openssl/openssl.git synced 2025-02-17 14:32:04 +08:00
Code Issues Packages Projects Releases Wiki Activity

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

Browse Source 
Submitted by: Nils Larsch
This commit is contained in:
Ulf Möller 2003-12-06 11:55:46 +00:00
parent a9f2330f43
commit 380e145daf
1 changed files with 46 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

91
crypto/bn/bn_add.c
View File

@ -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);
@ -117,11 +113,12 @@ int BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
if (a->top < b->top)
{ tmp=a; a=b; b=tmp; }
max=a->top;
min=b->top;
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++;
t1= *(ap++);
if ((*(rp++)=(t1+1)&BN_MASK2) >= t1)
dif--;
t1 = *(ap++);
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++)
*(rp++)= *(ap++);
}
/* memcpy(rp,ap,sizeof(*ap)*(max-i));*/
if (dif && rp != ap)
while (dif--)
/* copy remaining words if ap != rp */
*(rp++) = *(ap++);
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++;
t1= *(ap++);
t2=(t1-1)&BN_MASK2;
*(rp++)=t2;
if (t1 > t2) break;
dif--;
t1 = *(ap++);
t2 = (t1-1)&BN_MASK2;
*(rp++) = t2;
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;