Keyboard intercept (INT 15h, 4Fh)

        This function can be used to translate keys (fx. the 'A'-key can
        be translated into 'C' - usefull ...). It can also be used by
        programs, that wish to use hot-keys etc.

        Entry:
          AH = 4Fh
          AL = scan code
          CF = 1
        Return:
          If CF=1 then
                AL = scan code
          else
                No key is placed in buffer

        Note: Called by INT 9 handler to translate scan codes