Int B3 Fn 79  - Zipkey - Look Up Zipcodes For A Given City                 [U]

   AH = 79h
   BL = ZIPKEY state code of first state to search
   DS:SI -> city name, terminated with 0Dh if complete name, 00h if prefix

Return: AL = ZIPKEY state code of first matching state
   BH = number of matching entries (set to 51 if more than 50)
   DX = zipcode region of first match (0-999)
   CL = last two digits of first zipcode in first range (0-99)
   CH = last two digits of last zipcode in first range (0-99)

Note:  to find all matching cities, repeat search with BL set to one more than
     the returned AL

See Also: AH=78h,AH=7Ah