> UpCalls Title: UpCalls
Author: David De Vorchik
History:

        14-May-91 DDV Created.

This document covers the two UpCalls generated by DeviceFS. These are generated to inform the outside world that streams have been created or closed.

UpCall_StreamCreated

in: r0 = UpCall_StreamClosed

        r1  = parent handle
        r2  = 0 for RX, else TX
        r3  = FileSwitch handle being used
        r4  = internal device handle

out: all should be preserved.

This call is issued when a stream has been created. It serves as a broadcast and all registers should be preserved.

UpCall_StreamClosed

in: r0 = UpCall_StreamClosed

        r1  = parent handle
        r2  = 0 for RX, else TX
        r3  = FileSwitch handle being used
        r4  = internal device handle

out: -

This call is issued to inform the world that a stream has been closed.