Difference between revisions of "OSBYTE &71"

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[[Category:OSBYTE]]
 
[[Category:OSBYTE]]
OSBYTE &71 (113) - Select Main/Shadow for Display hardware
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{{PageTitle|OSBYTE &71 (113) - Select Main/Shadow for Display}}
 
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    On entry:
         X=0 Use whatever the default for the current mode is
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         X=0 Use whatever memory the current screen MODE uses
 
         X=1 Use main memory
 
         X=1 Use main memory
 
         X=2 Use shadow memory
 
         X=2 Use shadow memory
     (Risc OS 1.00)
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     On exit:
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        X=preserved
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    RISC OS:
 
     The value of X can be greater than 2 as well, and instructs the video
 
     The value of X can be greater than 2 as well, and instructs the video
 
     hardware to use the bank at screenbase+(X*modesize)
 
     hardware to use the bank at screenbase+(X*modesize)
  
 
This call specifies which bank of memory the Master video display hardware
 
This call specifies which bank of memory the Master video display hardware
access. Using this and [[OSBYTE &70]] a program can use the VDU to write to
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accesses. Using this and [[OSBYTE &70]] a program can use the VDU to write
one bank of memory while the other is being displayed.
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to one bank of memory while the other is being displayed.
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The setting is stored in the [[OSBYTE &FB]] variable.
  
==See Also==
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==See also==
* [[OSBYTE &6C]] - Select Master shadow memory
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* [[OSBYTE &49]] - Check for Integra-B shadow memory
* [[OSBYTE &6F]] - Select BBC B shadow memory
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* [[OSBYTE &6C]] - Select Master/Integra-B shadow memory
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* [[OSBYTE &6F]] - Select Aries/Watford shadow memory
 
* [[OSBYTE &70]] - Select memory for Master VDU access
 
* [[OSBYTE &70]] - Select memory for Master VDU access
 
* [[OSBYTE &71]] - Select memory for Master video display
 
* [[OSBYTE &71]] - Select memory for Master video display
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* http://mdfs.net/Docs/Comp/BBC/Osbyte00
 
* http://mdfs.net/Docs/Comp/BBC/Osbyte00
  
[[User:WikiSysop|WikiSysop]] 00:24, 29 August 2013 (BST)
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----
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[[User:Jgharston|Jgharston]] ([[User talk:Jgharston|talk]]) 01:12, 4 April 2015 (UTC)

Latest revision as of 19:28, 22 January 2021

OSBYTE &71 (113) - Select Main/Shadow for Display
   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 video
   hardware to use the bank at screenbase+(X*modesize)

This call specifies which bank of memory the Master video display hardware accesses. Using this and OSBYTE &70 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 &FB variable.

See also


Jgharston (talk) 01:12, 4 April 2015 (UTC)