GeneveOS Utility Functions

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:

UTIL   DATA 9
PARSE  DATA >0008
...
       LI   R0,PARSE        opcode
       LI   R2,PABADD+15    target buffer; here: name field of PAB
       LI   R3,>5000        first byte is maximum length of buffer
       MOVB R3,*R2
       CLR  R3              normal mode
       XOP  @UTIL,0
       JEQ  OK

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.

Utility functions

Opcode 0: Validate time

Checks whether the clock chip contains a valid time setting.

	Input	Output
R0	0000	-
Status	-	EQ=1 if time is valid

Opcode 8: Parse filename

	Input	Output
R0	0008	Delimiter
R1	Pointer to logical name	Error code
R2	Pointer to target buffer	-
R3	Alias flag	-
Status	-	EQ=1 when successfully parsed