Subversion Repositories planix.SVN

#include "os.h"

#include <mp.h>

#include "dat.h"

// res = s != 0 ? b1 : b2

void

mpsel(int s, mpint *b1, mpint *b2, mpint *res)

{

	mpdigit d;

	int n, m, i;

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

	if((res->flags & MPtimesafe) == 0){

		mpassign(s ? b1 : b2, res);

		return;

	}

	res->flags &= ~MPnorm;

	n = b1->top;

	m = b2->top;

	mpbits(res, Dbits*(n >= m ? n : m));

	res->top = n >= m ? n : m;

	s = (-s^s|s)>>(sizeof(s)*8-1);

	res->sign = (b1->sign & s) | (b2->sign & ~s);

	d = -((mpdigit)s & 1);

	i = 0;

	while(i < n && i < m){

		res->p[i] = (b1->p[i] & d) | (b2->p[i] & ~d);

		i++;

	}

	while(i < n){

		res->p[i] = b1->p[i] & d;

		i++;

	}

	while(i < m){

		res->p[i] = b2->p[i] & ~d;

		i++;

	}

}