Fixed Outline Multi-Bend Bus Driven Floorplanning

Wenxu Sheng1,  Sheqin Dong1,  Yuliang Wu2,  Satoshi Goto3
1Tsinghua University, 2The Chinese University of HongKong, 3WASEDA University


Modern hierarchical SOC design flows need to deal with fixed-outline floorplanning under the interconnect constraints, in this paper, we address the problem of bus driven floorplanning in a fixed-outline area. Given a set of blocks, the bus specification, and the height and width of the chip area, a floorplan solution including bus routes and satisfying the outline constraint will be generated with the total floorplan area and total bus area minimized. The approach proposed in this paper is based on a deterministic algorithm Less Flexibility First(LFF), which runs in a fixed-outline area and packs hard blocks one after another with no drawbacks. In our approach, we put no limitation to the shape of the buses, and the process block-packing and bus-packing are proceeding simultaneously, once a block is packed, the bus components that pass through this block are packed too. Experiment results show that under the constraint of fixed-outline, we can also obtain a good solution, with less dead space percentage and shorter run time, besides, for large test cases, our algorithm still works well.