Subversion Repositories planix.SVN

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

// sum = abs(b1) + abs(b2), i.e., add the magnitudes
void
mpmagadd(mpint *b1, mpint *b2, mpint *sum)
{
        int m, n;
        mpint *t;

        sum->flags |= (b1->flags | b2->flags) & MPtimesafe;

        // get the sizes right
        if(b2->top > b1->top){
                t = b1;
                b1 = b2;
                b2 = t;
        }
        n = b1->top;
        m = b2->top;
        if(n == 0){
                mpassign(mpzero, sum);
                return;
        }
        if(m == 0){
                mpassign(b1, sum);
                sum->sign = 1;
                return;
        }
        mpbits(sum, (n+1)*Dbits);
        sum->top = n+1;

        mpvecadd(b1->p, n, b2->p, m, sum->p);
        sum->sign = 1;

        mpnorm(sum);
}

// sum = b1 + b2
void
mpadd(mpint *b1, mpint *b2, mpint *sum)
{
        int sign;

        if(b1->sign != b2->sign){
                assert(((b1->flags | b2->flags | sum->flags) & MPtimesafe) == 0);
                if(b1->sign < 0)
                        mpmagsub(b2, b1, sum);
                else
                        mpmagsub(b1, b2, sum);
        } else {
                sign = b1->sign;
                mpmagadd(b1, b2, sum);
                if(sum->top != 0)
                        sum->sign = sign;
        }
}