Difference between revisions of "OSBYTE &70"

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OSBYTE &70 (112) - Select Main/Shadow for VDU access
 
OSBYTE &70 (112) - Select Main/Shadow for VDU access
  
        X=0 Use whatever the default for the current mode is
+
    Y=0 X=0 Use whatever the default for the current mode is
 
         X=1 Use main memory
 
         X=1 Use main memory
 
         X=2 Use shadow memory
 
         X=2 Use shadow memory
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     The value of X can be greater than 2 as well, and instructs the VDU
 
     The value of X can be greater than 2 as well, and instructs the VDU
 
     drivers to use the bank at screenbase+(X*modesize)
 
     drivers to use the bank at screenbase+(X*modesize)
 
This call specifies which bank of memory the Master VDU drivers access.
 
Using this and [[OSBYTE &71]] a program can use the VDU to write to one bank
 
of memory while the other is being displayed.
 
  
 
==See Also==
 
==See Also==
* [[OSBYTE &6C]] - Select Master 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:WikiSysop|WikiSysop]] 00:23, 29 August 2013 (BST)
+
[[User:Jgharston|Jgharston]] 21:45, 26 May 2009 (UTC)

Revision as of 02:13, 8 March 2015

OSBYTE &70 (112) - Select Main/Shadow for VDU access

   Y=0 X=0 Use whatever the default for the current mode is
       X=1 Use main memory
       X=2 Use shadow memory
   (Risc OS 1.00)
   The value of X can be greater than 2 as well, and instructs the VDU
   drivers to use the bank at screenbase+(X*modesize)

See Also

Jgharston 21:45, 26 May 2009 (UTC)