Moves data (defined by beginning and ending offset addresses)
    from one page location to another location on the same page.

    The number of bytes moved is:

    (old-offset-end) - (old-offset-start) + 1

    The sending field, defined by the old-offset arguments, remains
    unchanged.

    The receiving field, defined by the new-offset argument and the
    length of the sending field, is replaced by the contents of the
    sending field.

    Other information in the page is unchanged.