Subversion Repositories planix.SVN

#include "os.h"
#include <mp.h>
#include "dat.h"

// prereq: alen >= blen, sum has at least blen+1 digits
void
mpvecadd(mpdigit *a, int alen, mpdigit *b, int blen, mpdigit *sum)
{
        int i, carry;
        mpdigit x, y;

        carry = 0;
        for(i = 0; i < blen; i++){
                x = *a++;
                y = *b++;
                x += carry;
                if(x < carry)
                        carry = 1;
                else
                        carry = 0;
                x += y;
                if(x < y)
                        carry++;
                *sum++ = x;
        }
        for(; i < alen; i++){
                x = *a++ + carry;
                if(x < carry)
                        carry = 1;
                else
                        carry = 0;
                *sum++ = x;
        }
        *sum = carry;
}