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UKVDU23V
Programmer's Reference Manuals
» Part 1 - Introduction
» Vectors
» Software Vector Numbers
» UKVDU23V
Unknown VDU 23 Vector (23)
| Entry | |
|---|---|
| R0 | VDU 23 option |
| R1 | Pointer to VDU 23 queue |
| Exit | |
|---|---|
| R0 | Preserved |
| R1 | Preserved |
Use
This vector is called when a VDU 23 command is issued with an unknown parameter.
Notes
Whenever an unrecognised byte (18-25,28-31) is found following 23 in the VDU stream this vector is called. R0 contains this unknown byte – it is also the first of the 9 bytes in the VDU queue, pointed at by R1.
The default owner of this vector does nothing – unknown VDU 23 options are ignored.