result = UpfrontLayer( dummy, l )
    d0                     a0     a1
    LONG UpfrontLayer( LONG, 
struct Layer *);
    
 
  
    Move this layer to the most upfront position swapping bits in and out of the display with other layers. If this is a refresh layer then collect damage list and set the LAYERREFRESH bit in layer->Flags if redraw required. By clearing the BACKDROP bit in the layers Flags you may bring a Backdrop layer up to the front of all other layers.
    
      - Note: 
- 
        this operation may generate refresh events in other layers associated with this layer's Layer_Info structure.