Int 7F Fn 14  - Alloy Ntnx (host), Mw386 - Get Busy Pointer                [N]

   AH = 14h
   CL = 05h
   DX:DI -> buffer for busy structure (see below)

Return: DX:DI buffer filled

Format of busy structure:
Offset Size    Description
 00h   DWORD   pointer to busy flag byte
 04h   WORD    fixed port address (FF00h)