GeneveOS Device Operation
Accessing devices (floppy disk, hard disk, serial connector, printer) is possible in GeneveOS via XOP calls.
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 SF7 ...
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
|R0||Pointer to PAB||Pointer to PAB|
The actual operation is contained in the Peripheral Access Block (PAB).