Corner Block List (CBL) was recently proposed as an efficient representation for MOSAIC packing of rectangles. Although the original method is really innovative, there still remains room of improvement for our purpose. This paper proposes a compact algorithm for placement based on corner block list. By introducing the dummy blocks in CBL, our algorithm can intellective employ dummy blocks in the packing to represent the placement including empty rooms, which corner block list cannot represent. Our algorithm can obtain the fast convergence to an optimal solution. Based on the compact approach, we propose a new way to handle arbitrary shaped rectilinear modules. The experimental results are demonstrated by some benchmark data and the performance shows effectiveness of the proposed method.