Difference between revisions of "GeneveOS Device Operation"
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m (→User-task XOPs) |
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| Line 11: | Line 11: | ||
XOP @FILE,0 | XOP @FILE,0 | ||
MOVB @PABADD+2,R0 | MOVB @PABADD+2,R0 | ||
JNE | JNE ERROR | ||
... | ... | ||
Revision as of 19:13, 17 July 2016
Accessing devices (floppy disk, hard disk, serial connector, printer) is possible in GeneveOS via XOP calls.
User-task XOPs
User-task XOPs are available for use in application programs. Here is a typical example:
PABADD EQU >F180
FILE DATA 8
...
LI R0,PABADD
XOP @FILE,0
MOVB @PABADD+2,R0
JNE ERROR
...
Similar as with the TI-99/4A device service routine concept (DSR), a Peripheral Access Block (PAB) must be set up prior to invoking the XOP.
Device Service Routine Call
| Input | Output | |
|---|---|---|
| R0 | Pointer to PAB | Pointer to PAB |
The actual operation is contained in the Peripheral Access Block (PAB).