Down
current = Down(current);
current = Down(current);
if (Down(current) == (ITEM *)0) {
current = Down(current);
Down(i) = IthItem(m, n + Cols(m));
Down(i) = (ITEM *) NULL;
Down(i) = IthItem(m, Nitems(m)-1);
Down(IthItem(m, up)) = IthItem(m, n);
Down(i) = (r == Rows(m)-1) ? (ITEM *)0 : IthItem(m, n+1);
Down(IthItem(m, n-1)) = IthItem(m, n - Rows(m));
Down(IthItem(m, up)) = IthItem(m, n);
} while ((i = Down(i)) != si);