#include "bn_lcl.h"
/* r can == a or b */
-int BN_add(BIGNUM *r, BIGNUM *a, BIGNUM *b)
+int BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
{
- BIGNUM *tmp;
+ const BIGNUM *tmp;
+ int a_neg = a->neg;
bn_check_top(a);
bn_check_top(b);
* -a + b b-a
* -a + -b -(a+b)
*/
- if (a->neg ^ b->neg)
+ if (a_neg ^ b->neg)
{
/* only one is negative */
- if (a->neg)
+ if (a_neg)
{ tmp=a; a=b; b=tmp; }
/* we are now a - b */
return(1);
}
- if (a->neg) /* both are neg */
+ if (!BN_uadd(r,a,b)) return(0);
+ if (a_neg) /* both are neg */
r->neg=1;
else
r->neg=0;
-
- if (!BN_uadd(r,a,b)) return(0);
return(1);
}
/* unsigned add of b to a, r must be large enough */
-int BN_uadd(BIGNUM *r, BIGNUM *a, BIGNUM *b)
+int BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
{
register int i;
int max,min;
BN_ULONG *ap,*bp,*rp,carry,t1;
- BIGNUM *tmp;
+ const BIGNUM *tmp;
bn_check_top(a);
bn_check_top(b);
*(rp++)= *(ap++);
}
/* memcpy(rp,ap,sizeof(*ap)*(max-i));*/
+ r->neg = 0;
return(1);
}
/* unsigned subtraction of b from a, a must be larger than b. */
-int BN_usub(BIGNUM *r, BIGNUM *a, BIGNUM *b)
+int BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
{
int max,min;
register BN_ULONG t1,t2,*ap,*bp,*rp;
#endif
r->top=max;
+ r->neg=0;
bn_fix_top(r);
return(1);
}
-int BN_sub(BIGNUM *r, BIGNUM *a, BIGNUM *b)
+int BN_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
{
int max;
int add=0,neg=0;
- BIGNUM *tmp;
+ const BIGNUM *tmp;
bn_check_top(a);
bn_check_top(b);