Difference between revisions of "OSBYTE &71"
m (Corrected OSBYTE variable location.) |
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[[Category:OSBYTE]] | [[Category:OSBYTE]] | ||
| − | OSBYTE &71 (113) - Select Main/Shadow for Display | + | {{PageTitle|OSBYTE &71 (113) - Select Main/Shadow for Display}} |
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On entry: | On entry: | ||
X=0 Use whatever memory the current screen MODE uses | X=0 Use whatever memory the current screen MODE uses | ||
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* [[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 | ||
| − | * [[OSBYTE &6F]] - Select | + | * [[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 | ||
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[[User:Jgharston|Jgharston]] ([[User talk:Jgharston|talk]]) 01:12, 4 April 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
- OSBYTE &49 - Check for Integra-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 &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
