Difference between revisions of "GeneveOS Device Operation"

Revision as of 19:12, 17 July 2016

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.

	Input	Output
R0	Pointer to PAB	Pointer to PAB

The actual operation is contained in the Peripheral Access Block (PAB).

@@ Line 16: / Line 16: @@
 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 ===
+=== Device Service Routine Call ===
-'''Opcode: 0'''
 {| class="xoparg"
@@ Line 26: / Line 24: @@
 |-
 | R0
-| Opcode (0000) || Error code (always 0)
+| Pointer to PAB || Pointer to PAB
-|-
-| 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.
+The actual operation is contained in the Peripheral Access Block (PAB).