Int 4B - Acorn Bbc Master 512 - "osbyte" - Misc Functions Using Register [O]
AL = function code
BL = first parameter
BH = second parameter (if needed)
Return: BL = first return parameter
BH = second return parameter
CF depends on function
See Also: INT 40"Acorn",INT 4A"Acorn",INT 4C"Acorn"