\ VIDEO.HLP     Direct VIDEO Screen output              by Tom Zimmer

VTSEG           ( --- a1 )
        A variable that holds the segment value of the source where
        text is typed from.  Normally set to the value of ?CS:, but
        is changed by the editor to display text from an external
        edit buffer segment.

VIDEO-SEG       ( --- a1 )
        A variable that holds the segment value of the display screen.

ATTRIB          ( --- a1 )
        A variable that holds the value of the current display
        attributes. The value 7 is the default for normal video.

?VMODE          ( --- N1 )
        Read the current video mode from the BIOS. A value of 7 is
        normal for monochrome, and a value of 2 is a CGA board.

INITMONO        ( --- )
        A defered word that gets set later, and is used to do the
        monochrome display attribute control initialization
        ( it sets the >ATTRIBx words. ). See the file MONOCROM.SEQ.

INITCOLOR       ( --- )
        A defered word that gets set later, and is used to do the
        color display attribute control initialization ( it sets the
        >ATTRIBx words. ). See the file MONOCROM.SEQ, and COLOR.SEQ.

VMODE.SET       ( --- )
        Set the VIDEO-SEG variable after testing the current video
        mode, and perform any needed initialization required by
        executing the INITMONO, or INITCOLOR as needed.

VTYPE           ( string length x y -- )
        A direct screen type. The text "string" is blasted to the
        current display for "length", starting at screen column x
        and row y. The cursor is left positioned at the end of the
        text string.

        Additional notes on VTYPE:

        The variable VTSEG holds the segment value of the source of
        the video type, normally Forths Code segment.  VIDEO-SEG
        holds the segment of the destination of the video type, that
        is where your video board is addressed.  This makes it
        possible to type to the display from a segment other than
        Forths Code segment.  This is done by the editor, which
        displays lines of source directly from the external memory
        buffer to avoid having to move the data into Forth code
        segment.



