GeneveOS XOP Definitions
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GeneveOS makes frequent use of XOPs and offers them for user programs. An XOP (extended operation) is a special command of the TMS processor family which causes a context switch, transferring control to a location that is specified in a table.
Compared to common architecture concepts, the XOP is TI's way of implementing a system call.
The XOP instruction takes two arguments; the first delivers data for the call, the second is a number from 0 to 15 and indicates the XOP number. In GeneveOS, all system calls are XOP 0 with specific arguments:
ARGUM DATA <number>
...
XOP @ARGUM,0
...
Overview
| XOP argument | Category |
|---|---|
| 5 | Keyboard |
| 6 | Video display |
| 7 | Memory Management |
| 8 | Devices (Files) |
| 9 | Utility functions |
| 10 | Mathematical functions |
Used workspaces
The XOPs use workspaces F0C0 and F0A0.