Difference between revisions of "OSBYTE &70"
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OSBYTE &70 (112) - Select Main/Shadow for VDU access | OSBYTE &70 (112) - Select Main/Shadow for VDU access | ||
| + | On entry: | ||
X=0 Use whatever the default for the current mode is | X=0 Use whatever the default for the current mode is | ||
X=1 Use main memory | X=1 Use main memory | ||
X=2 Use shadow memory | X=2 Use shadow memory | ||
| − | + | RISC OS: | |
The value of X can be greater than 2 as well, and instructs the VDU | The value of X can be greater than 2 as well, and instructs the VDU | ||
drivers to use the bank at screenbase+(X*modesize) | drivers to use the bank at screenbase+(X*modesize) | ||
| Line 14: | Line 15: | ||
==See Also== | ==See Also== | ||
| − | * [[OSBYTE &6C]] - Select Master shadow memory | + | * [[OSBYTE &49]] - Check for Integra-B shadow memory |
| + | * [[OSBYTE &6C]] - Select Master/Integra-B shadow memory | ||
* [[OSBYTE &6F]] - Select BBC B shadow memory | * [[OSBYTE &6F]] - Select BBC B shadow memory | ||
* [[OSBYTE &70]] - Select memory for Master VDU access | * [[OSBYTE &70]] - Select memory for Master VDU access | ||
| Line 24: | Line 26: | ||
* http://mdfs.net/Docs/Comp/BBC/Osbyte00 | * http://mdfs.net/Docs/Comp/BBC/Osbyte00 | ||
| − | [[User: | + | [[User:Jgharston|Jgharston]] ([[User talk:Jgharston|talk]]) 20:30, 3 April 2015 (UTC) |
Revision as of 21:30, 3 April 2015
OSBYTE &70 (112) - Select Main/Shadow for VDU access
On entry:
X=0 Use whatever the default for the current mode is
X=1 Use main memory
X=2 Use shadow memory
RISC OS:
The value of X can be greater than 2 as well, and instructs the VDU
drivers to use the bank at screenbase+(X*modesize)
This call specifies which bank of memory the Master VDU drivers access. Using this and OSBYTE &71 a program can use the VDU to write to one bank of memory while the other is being displayed.
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
