mulint( a, b, c )
	mp a, b, c;
	/* Multiply two integers.  a*b-->c */
	
	{int i, j, la, lb;
	/* b and c may coincide */
	la = length(a); lb = length(b);
	for (i=0; i<la-2; i++)	c[lb+i] = 0;
	for (i=lb-1; i>0; i--)	{
		for (j=2; j<la; j++)
			if ( (c[i+j-1] += b[i]*a[j]) > 
				MAXD-(BASE-1)*(BASE-1)-MAXD/BASE )	{
				c[i+j-1] -= (MAXD/BASE)*BASE;
				c[i+j] += MAXD/BASE;
				}
		c[i] = b[i]*a[1];
		}
	storelength( c, la+lb-2 );
	storesign( c, sign(a)==sign(b) ? POS : NEG );
	normalize( c );
	};