all documentation i've seen on port 0 has said that the byte sent to it is added to $c0, then multiplied by $0100 to become the pointer to the display memory. however, i've found that when i made a prog which sent a value greater than $3c to port 0, ($76) and used $fc00 as a double buffer, copying the entire contents of $fc00 to $f600 seemed to make it display. any ideas why? port 0 is REALLY confusing!