Function 07h (7)         Direct Console Character Input without Echo

    Waits for a character from the standard input device. Does not echo,
    and does not check for Ctrl-Break or Ctrl-C.

       On entry:      AH         07h

       Returns:       AL         Character

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    This function waits for a character from the standard input device.
    When a character is available, the function returns its ASCII value in
    AL but does not echo it to the standard output device.

       Notes:         A 0 returned in AL means that one of the "special"
                      characters (a function key or a cursor key, for
                      example) was input. Call the function again to read
                      the extended code of the special character (see the
                      Key codes table).

                      Does not execute an INT 23h in response to Ctrl-
                      Break or Ctrl-C.