INT 7F - Alloy NTNX, MW386 - DIRECT MEMORY TRANSFER
        AH = 16h
        DX:SI -> transfer structure (see below)
Return: AL = status
            00h successful
            0Ah source or destination out of range
            0Bh transfer kernal busy--try again
Notes:  this call transfers memory contents directly between users; both source
          and destination user IDs may differ from the caller's ID
        no segment wrap is allowed

Format of transfer structure:
Offset  Size    Description
 00h    WORD    bytes to transfer
 02h    BYTE    source ID
                FEh = caller
 03h    DWORD   source address
 07h    BYTE    destination ID
                FFh = all slaves except caller
                FEh = caller
 08h    DWORD   destination address