Int E0  - Real/32 - "dev_waitflag" - Wait On System Flag                   [O]

   CL = 84h
   DX = system flag ID

Return: AX = status (0000h success, else error code)
   if successful, this function does not return until the system flag has
     been set by an interrupt handler (see INT E0/CL=85h); if the flag was
     already set, this call returns immediately

See Also: INT E0/CL=85h,INT E0/CL=B7h