EXOS 2.1 Constants

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6. Special Function Sub­function Codes

All special function calls pass a sub­function number in register B. This defines what special function is required. The codes for the functions supported by the built in devices are listed here, along with which device they apply to. Details of the action of these calls can be found in the appropriate device driver specification.

VIDEO

01h @@DISP Display video page on screen

02h @@SIZE Return page size and mode

03h @@ADDR Return page size

04h @@FONT Re­initialise character font

KEYBOARD

08h @@FKEY Program a function key

09h @@JOY Read joystck (internal or external)

NET

10h @@FLSH Flush buffer

11h @@CLR Clear buffers

EDITOR

18h @@MARG Set margin positions

19h @@CHLD Load a document file

1ah @@CHSV Save a document file

Next Chapter: Acttion Codes for System Extensions.