INT 2F - DOS v5.0 DOSKEY - READ INPUT LINE FROM CONSOLE
        AX = 4810h
        DS:DX -> line buffer (see INT 21/AH=0Ah)
Return: AX = 0000h if successful
Notes:  the first byte (length) of the buffer MUST be 80h, or DOSKEY chains to
          the previous handler
        if the user's input is a macro name, no text is placed in the buffer
          even though AX=0000h on return; the program must immediately issue
          this call again to retrieve the expansion of the macro.  Similarly,
          if the user enters a special parameter such as $*, this call must
          be repeated to retrieve the expansion; on the second call, DOSKEY
          overwrites the macro name on the screen with its expansion.
SeeAlso: INT 21/AH=0Ah