GraphicsV 16
GraphicsV
» GraphicsV 16
Graphics Vector (42)
| Entry | |
|---|---|
| R0 | Suggested mode number or Mode Selector Block |
| R4 | Bits 0-23: 16 (reason code) |
| Bits 24-31: Driver number |
| Exit | |
|---|---|
| R0 | Mode number/selector to use |
| R4 | 0 |
| - | All other registers preserved |
Use
This call allows a GraphicsV driver to override the choice of screen mode in certain situations, e.g. on driver startup, or the default mode used by the Wimp. For example, a device with a fixed size LCD may want to select a mode which fills the display.
Notes
The kernel issues this call from within OS_ReadSysInfo 1. However it will only issue it under certain circumstances – see the OS_ReadSysInfo page for details.
If the mode returned refers to a mode definition which is not one of the kernel’s numbered modes, a suitable mode definition needs to have been loaded, e.g. from a ResourceFS based built in MDF. Service_ModeExtension can then subsequently find it and provide the relevant settings. If there is not a mode definition file, a custom Service_ModeExtension response needs to be provided.
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