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    QBSBlit -- Synchronize the blitter request with the video beam.


    QBSBlit( bsp )

    void QBSBlit( struct bltnode * );

    Call a user routine for use of the blitter, enqueued separately from
    the QBlit queue.  Calls the user routine contained in the blit
    structure when the video beam is located at a specified position
    onscreen.   Useful when you are trying to blit into a visible part
    of the screen and wish to perform the data move while the beam is
    not trying to display that same area.  (prevents showing part of
    an old display and part of a new display simultaneously).  Blitter
    requests on the QBSBlit queue take precedence over those on the
    regular blitter queue. The beam position is specified the blitnode.

    bsp - pointer to a blit structure.  See description in the
         Graphics Support section of the manual for more info.

    User routine is called when the QBSBlit queue reaches this
    request AND the video beam is in the specified position.
    If there are lots of blits going on and the video beam
    has wrapped around back to the top it will call all the
    remaining bltnodes as fast as it can to try and catch up.

    Not very smart when getting blits from different tasks.
    They all get put in same queue so there are unfortunately
    some interdependencies with the beam syncing.

    QBlit() hardware/blit.h

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