.OUT FILES:
    -----------

    These files are produced when logging OUTs; see menu option O in the
    Extra Functions menu.  For the specified I/O ports, all OUTs to these
    ports are recorded in the .OUT file, together with the exact time at
    which the OUTs were executed.

    An .OUT file consists of a string of 5-byte blocks.  The first word is
    the timing word; it has a value between 0 and 17471 inclusive, and a
    unit value corresponds to 1 T state (=1/3494400 s).  After this, the
    OUT port that was written to follows, then the value OUTed itself:

        Offset  Length  Description

        0       2       Time (0-17471)
        2       2       Port address
        4       1       Value

    Every 1/200th of an emulated second, that is, every 69888/4=17472 T
    states, a time-wraparound block is written to the .OUT file.  This
    block has #FFFF as first word; the other three bytes have no meaning.
    So even when the Spectrum does not OUT to the specified port at all,
    1000 bytes get written to the log file every second.

    By default, an OUT to an even I/O address which does not change the
    state of the MIC and EAR outputs is not written to the .OUT file, to
    save disk space when recording music.  If you want all OUTs, specify
    -xg on the command line.