queueFlags

Dd.q aAtT
|||| |||+- is drawing tiles
|||| ||+-- draw box tiles (0) / restore old tiles (1)
|||| |+--- is writing attributes
|||| +---- write box attributes (0) / restore old attributes (1) 
|||+------ attribute queue is set up
||+------- (unused)
|+-------- are we creating (0) or restoring (1) tiles
+--------- initiate drawing a new box