Difference between revisions of "OSBYTE &73"

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OSBYTE &73 (115) - Select shadow RAM bank used
 
OSBYTE &73 (115) - Select shadow RAM bank used
  
 +
    On entry:
 
         X=0 Shadow bank 8
 
         X=0 Shadow bank 8
 
         X=1 Shadow bank 9
 
         X=1 Shadow bank 9
     (Electron OS only)
+
      
 +
    Electron OS:
 
     Blank/restore palette
 
     Blank/restore palette
     X=0  restores the palette
+
     On entry:
    X<>0 sets the whole palette to black if is high resolution mode
+
        X=0  restores the palette, on exit X=0
     Software using NMIs in high res modes can prevent snow appearing on the
+
        X<>0 sets the whole palette to black if in high resolution mode
    screen during NMIs (due to ULA reuse) by blanking the palette
+
            on exit, X<4
 +
      
 +
Software using NMIs in high resolution screen modes can prevent snow
 +
appearing on the screen during NMIs (due to ULA reuse) by blanking the
 +
palette.
  
==See Also==
+
==See also==
 +
* [[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]] 21:52, 26 May 2009 (UTC)
 
[[User:Jgharston|Jgharston]] 21:52, 26 May 2009 (UTC)
 +
[[User:Jgharston|Jgharston]] ([[User talk:Jgharston|talk]]) 20:32, 3 April 2015 (UTC)

Latest revision as of 21:32, 3 April 2015

OSBYTE &73 (115) - Select shadow RAM bank used

   On entry:
       X=0 Shadow bank 8
       X=1 Shadow bank 9
   
   Electron OS:
   Blank/restore palette
   On entry:
       X=0  restores the palette, on exit X=0
       X<>0 sets the whole palette to black if in high resolution mode
            on exit, X<4
   

Software using NMIs in high resolution screen modes can prevent snow appearing on the screen during NMIs (due to ULA reuse) by blanking the palette.

See also

Jgharston 21:52, 26 May 2009 (UTC) Jgharston (talk) 20:32, 3 April 2015 (UTC)