Difference between revisions of "OSBYTE &71"

From BeebWiki
Jump to: navigation, search
(update)
(See Also)
 
(7 intermediate revisions by 2 users not shown)
Line 1: Line 1:
 
[[Category:OSBYTE]]
 
[[Category:OSBYTE]]
OSBYTE &71 (113) - Select Main/Shadow for Display hardware
+
{{PageTitle|OSBYTE &71 (113) - Select Main/Shadow for Display}}
 
+
    On entry:
         X=0 Use whatever the default for the current mode is
+
         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)
+
     On exit:
 +
        X=preserved
 +
    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
+
accesses. Using this and [[OSBYTE &70]] a program can use the VDU to write
one bank of memory while the other is being displayed.
+
to one bank of memory while the other is being displayed.
 +
 
 +
The setting is stored in the [[OSBYTE &FB]] variable.
  
==See Also==
+
==See also==
* [[OSBYTE &6C]] - Select Master shadow memory
+
* [[OSBYTE &49]] - Check for Integra-B shadow memory
* [[OSBYTE &6F]] - Select BBC B shadow memory
+
* [[OSBYTE &6C]] - Select Master/Integra-B shadow memory
 +
* [[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
Line 24: Line 29:
 
* http://mdfs.net/Docs/Comp/BBC/Osbyte00
 
* http://mdfs.net/Docs/Comp/BBC/Osbyte00
  
[[User:WikiSysop|WikiSysop]] ([[User talk:WikiSysop|talk]]) 13:33, 8 March 2015 (UTC)
+
----
 +
[[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)