Difference between revisions of "OSBYTE &75"

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m (moved OSBYTE 75 to OSBYTE &75)
 
m (Bit 4 is also used on the BBC B+.)
 
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OSBYTE &75 (117) - Read VDU Status Byte
 
OSBYTE &75 (117) - Read VDU Status Byte
  
 +
    On exit:
 
     X=b0 Print output enabled by VDU2
 
     X=b0 Print output enabled by VDU2
       b1 Unused
+
       b1 Scrolling disabled
 
       b2 Paged scrolling selected by VDU14
 
       b2 Paged scrolling selected by VDU14
       b3 Text window in force ie.software scrolling
+
       b3 Text window in force, ie software scrolling
       b4 In a shadow mode
+
       b4 In a shadow mode on Master
 
       b5 In VDU5 mode
 
       b5 In VDU5 mode
 
       b6 Cursor editing in progress
 
       b6 Cursor editing in progress
 
       b7 Screen disabled with VDU21
 
       b7 Screen disabled with VDU21
    (Acorn MOS 1.20)
 
      b1 Scrolling disabled
 
  
==See Also==
+
Note, bit 4 is only set by shadow screen modes on the Master series and the
 +
BBC B+. With shadow screen systems on the BBC B and Electron 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
 
* http://mdfs.net/Docs/Comp/BBC/Osbyte00
  
 
[[User:Jgharston|Jgharston]] 21:53, 26 May 2009 (UTC)
 
[[User:Jgharston|Jgharston]] 21:53, 26 May 2009 (UTC)
 +
[[User:Jgharston|Jgharston]] ([[User talk:Jgharston|talk]]) 20:33, 3 April 2015 (UTC)

Latest revision as of 08:46, 28 December 2016

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 and the BBC B+. With shadow screen systems on the BBC B and Electron a different flag is used.

See also

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