Difference between revisions of "OSBYTE &71"

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OSBYTE &71 (113) - Select Main/Shadow for Display hardware
 
OSBYTE &71 (113) - Select Main/Shadow for Display hardware
  
    Y=0 X=as per OSByte &70
+
        X=0 Use whatever the default for the current mode is
     The value of X defines which bank the hardware will output
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        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 video
 +
    hardware to use the bank at screenbase+(X*modesize)
 +
 
 +
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
 +
one bank of memory while the other is being displayed.
  
 
==See Also==
 
==See Also==
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* [[OSBYTE &6C]] - Select Master shadow memory
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* [[OSBYTE &6F]] - Select BBC B shadow memory
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* [[OSBYTE &70]] - Select memory for Master VDU access
 +
* [[OSBYTE &71]] - Select memory for Master video display
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* [[OSBYTE &72]] - Select future use of shadow memory
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* [[OSBYTE &73]] - Select shadow bank
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* [[OSBYTE &74]] - Check for Solidisk shadow memory
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* [[Paging in video memory]]
 
* http://mdfs.net/Docs/Comp/BBC/Osbyte00
 
* http://mdfs.net/Docs/Comp/BBC/Osbyte00
  
[[User:Jgharston|Jgharston]] 21:46, 26 May 2009 (UTC)
+
[[User:WikiSysop|WikiSysop]] ([[User talk:WikiSysop|talk]]) 13:33, 8 March 2015 (UTC)

Revision as of 14:33, 8 March 2015

OSBYTE &71 (113) - Select Main/Shadow for Display hardware

       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 video
   hardware to use the bank at screenbase+(X*modesize)

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 one bank of memory while the other is being displayed.

See Also

WikiSysop (talk) 13:33, 8 March 2015 (UTC)