Abstract — In this paper, we introduce the concept of the P*-admissible representation and propose a P*-admissible, transitive closure graph-based representation for general floorplans, called TCG, and show its superior properties. TCG combines the advantages of popular representations such as sequence pair, BSG, and B*-tree. Like sequence pair and BSG, but unlike O-tree, B*-tree, and CBL, TCG is P*-admissible. Like B*-tree, but unlike sequence pair, BSG, O-tree, and CBL, TCG does not need to construct additional constraint graphs for the cost evaluation during packing, implying faster runtime. Further, TCG supports incremental update during operations and keeps the information of boundary modules as well as the shapes and the relative positions of modules in the representation. More importantly, the geometric relation among modules is transparent not only to the TCG representation but also to its operations, facilitating the convergence to a desired solution. All these properties make TCG an effective and flexible representation for handling the general floorplan/placement design problems with various constraints. Experimental results show the promise of TCG.

After the discussion on the difference between floorplanning and packing in VLSI placement design, this paper adapts the floorplanner that is based on the Q-sequence to a packing algorithm. For the purpose, some empty room insertion is required to guarantee not to miss the optimum packing. To increase the performance in packing, a new move that perturbs the floorplan is introduced in terms of the ParenthesisTree Pair. A Simulated Anealing based packing search algorithm was implemented. Experimental results showed the effect of empty room insertion.