Radeon_MoveDisplay
Radeon_MoveDisplay( ai, hds, vds );
Radeon_MoveDisplay( ai, 0, 0 );
Radeon_MoveDisplay( ai, mode.h_display_start, mode.v_display_start );
result = Radeon_MoveDisplay( ai, h_display_start, v_display_start );
status_t Radeon_MoveDisplay( accelerator_info *ai, uint16 h_display_start, uint16 v_display_start );