Int B3 Fn 78  - Zipkey - Look Up Zipcodes For A Given State And City       [U]

   AH = 78h
   BL = ZIPKEY state code
   DS:SI -> city name, terminated with 0Dh if complete name, 00h if prefix

Return: 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 the range (0-99)
   CH = last two digits of last zipcode in the range (0-99)
   AX destroyed

See Also: AH=79h,AH=7Ah