Late Breaking Results: Routability-Driven FPGA Macro Placement Considering Complex Cascade Shape and Region Constraints

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Abstract
Field-programmable gate array (FPGA) macro placement holds a crucial role within the FPGA physical design flow since it substantially influences the subsequent stages of cell placement and routing. In this paper, we propose an effective and efficient routability-driven macro placement algorithm for modern FPGAs with cascade shape and region constraints. To reserve adequate space for cell placement and guarantee routability, we first develop a routability-driven mixed-size analytical global placement (GP) that evenly distributes both macros and cells while considering cascade shape and region constraints. Then, we propose an integer linear programming (ILP)-based cascade shape legalization (LG) followed by matching-based macro legalization to remove macro overlaps while satisfying the region constraints. Finally, a routability-driven detailed macro placement is proposed to refine the solution. Compared with the top contestants of the MLCAD 2023 contest, experimental results show that our algorithm achieves the best overall score and routability.
Funding Information
  • National Key Research and Development Program of China (2022YFB4400500)
  • National Natural Science Foundation of China (62104037)