OSBYTE &75

OSBYTE &75 (117) - Read VDU Status Byte

   On exit:
   X=b0 Print output enabled by VDU2
     b1 Scrolling disabled
     b2 Paged scrolling selected by VDU14
     b3 Text window in force, ie software scrolling
     b4 In a shadow mode on Master
     b5 In VDU5 mode
     b6 Cursor editing in progress
     b7 Screen disabled with VDU21

Note, bit 4 is only set by shadow screen modes on the Master series. With other shadow screen systems a different flag is used.

See also

• OSWRCH
• OSBYTE &49 - Check for Integra-B shadow memory
• OSBYTE &6C - Select Master/Integra-B shadow memory
• OSBYTE &6F - Select BBC B shadow memory
• OSBYTE &70 - Select memory for Master VDU access
• OSBYTE &71 - Select memory for Master video display
• OSBYTE &72 - Select future use of shadow memory
• OSBYTE &73 - Select shadow bank
• OSBYTE &74 - Check for Solidisk shadow memory
• Paging in video memory
• http://mdfs.net/Docs/Comp/BBC/Osbyte00

Jgharston 21:53, 26 May 2009 (UTC) Jgharston (talk) 20:33, 3 April 2015 (UTC)