Difference between revisions of "OSBYTE &70"

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The setting is stored in the [[OSBYTE &FA]] variable.
 
The setting is stored in the [[OSBYTE &FA]] variable.
  
==See Also==
+
==See also==
 
* [[OSBYTE &49]] - Check for Integra-B shadow memory
 
* [[OSBYTE &49]] - Check for Integra-B shadow memory
 
* [[OSBYTE &6C]] - Select Master/Integra-B shadow memory
 
* [[OSBYTE &6C]] - Select Master/Integra-B shadow memory

Latest revision as of 19:27, 22 January 2021

OSBYTE &70 (112) - Select Main/Shadow for VDU access
   On entry:
       X=0 Use whatever memory the current screen MODE uses
       X=1 Use main memory
       X=2 Use shadow memory
   On exit:
       X=preserved
   RISC OS:
   The value of X can be greater than 2 as well, and instructs the VDU
   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.

The setting is stored in the OSBYTE &FA variable.

See also


Jgharston (talk) 01:11, 4 April 2015 (UTC)