Initialised by the routine at NEW, read by the routines at PO_TV_2, PO_STORE, PO_FETCH, TEMPS, CL_SET and CL_LINE, and updated by the routines at SA_CONTRL, PO_SCR, CLS, KEY_INPUT, ED_COPY, MAIN_EXEC, WAIT_KEY, CHAN_K, CHAN_S, AUTO_LIST, LIST, CLASS_07, CLASS_09 and INPUT. This system variable is accessed by some routines via the IY register at IY+$02.

Bit	Description
0	Set when printing to the lower screen
1	Unused
2	Unused
3	Set when the input mode has changed
4	Set when an automatic listing is being produced
5	Set when the lower screen needs clearing
6	Unused
7	Unused