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

   CL = B7h
   DS:DX -> Flag Parameter Block (FPB) (see #3785)

Return: AX = status
   may destroy SI,DI,DS

Note:  if the flag was already set, this function returns immediately

See Also: INT E0/CL=84h,INT E0/CL=85h

Format of REAL/32 Flag Parameter Block (FPB):
Offset Size    Description (Table 3785)
 00h   WORD    number of system flag on which to wait
 02h   WORD    maximum number of system ticks (see INT E0/CL=9Ah) to wait