Difference between revisions of "OSBYTE &70"
m (moved OSBYTE 70 to OSBYTE &70) |
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| Line 2: | Line 2: | ||
OSBYTE &70 (112) - Select Main/Shadow for VDU access | OSBYTE &70 (112) - Select Main/Shadow for VDU access | ||
| − | + | 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 | ||
| Line 8: | Line 8: | ||
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) | ||
| + | |||
| + | 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== | ==See Also== | ||
| + | * [[OSBYTE &6C]] - Select Master 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: | + | [[User:WikiSysop|WikiSysop]] 00:23, 29 August 2013 (BST) |
Revision as of 00:23, 29 August 2013
OSBYTE &70 (112) - Select Main/Shadow for VDU access
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 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 &6C - Select Master 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
WikiSysop 00:23, 29 August 2013 (BST)
