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.
Available memory pages
|R0||Opcode (0000)||Error code (always 0)|
|R1||Number of free pages|
|R2||Number of fast free pages|
|R3||Total number of pages in system|
This function is used to query the free space in the system. No changes are applied. The total number of pages are the maximum number of allocatable pages.