mda_addr
u16 *dest = mda_addr(x, y);
u16 *dest = mda_addr(x, y);
scr_memmovew(mda_addr(0, t), mda_addr(0, t + lines),
scr_memsetw(mda_addr(0, b - lines), eattr,
scr_memmovew(mda_addr(0, t + lines), mda_addr(0, t),
scr_memsetw(mda_addr(0, t), eattr, lines*mda_num_columns*2);