Showing changes from revision #0 to #1:
Added | Removed | Changed
Entry | |
---|---|
R0 | Reason |
R1 | 222 (&DE) |
R2 | New display number |
R3 | 0 |
# | Hex # | Action |
---|---|---|
0 | &00 | Display is in process of being changed |
1 | &01 | Display change complete |
This service call is issued by OS_ScreenMode 11 when the OS is switching to a different video driver. Reason 0 will be issued at the start of the operation, in order to allow components which handle screen mode processing (e.g. ScreenModes) to prepare themselves. Once the call is complete the kernel will attempt to select a screen mode for the new display. If this succeeds reason code 1 will be issued in order to notify software that the change is complete. If the mode change fails the kernel will attempt to restore the previous driver, which will result in reason code 0 being issued again.
The value of R3 is a sub-reason code. The value 0 indicates that the mode has been reselected. Other values may indicate alternate behaviour in future.
Under RISC OS 5, the display number in R2 corresponds to the GraphicsV driver number. Additionally, VDU variable 192 will have already been updated with the new driver number at the time reason code 0 is issued.
Under RISC OS Select, the display number in R2 corresponds to the VideoV? driver number.