考虑模块翻转和空白区域再分配的基于静电场的固定边框布图规划  

Electrostaticbased fixedoutline floorplanning considering module flipping and whitespace redistribution

作　　者：刘端祥 黄富兴 李兴权 朱文兴[1] LIU Duanxiang;HUANG Fuxing;LI Xingquan;ZHU Wenxing(Center for Discrete Mathematics and Theoretical Computer Science,Fuzhou University,Fuzhou 350108,China;Pengcheng Laboratory,Shenzhen 518000,China)

机构地区：[1]福州大学离散数学与理论计算机科学研究中心,福州350108 [2]鹏城实验室,深圳518000

出　　处：《集成电路与嵌入式系统》2024年第1期46-57,共12页INTEGRATED CIRCUITS AND EMBEDDED SYSTEMS

基　　金：国家自然科学基金(62174033);鹏城实验室重大攻关项目(PCL2023A03)。

摘　　要：目前,基于解析方法的布图规划取得了很好的结果,模块翻转有实际应用场景且可以进一步优化结果,但解析方法尚无法处理模块翻转问题。因此,本文首次尝试使用统一的解析方法来解决这一问题,提出了一种新的力,即翻转力。在总体布图规划阶段,翻转力能根据线长将每个模块翻转到理想的方向。此外,基于静电场模型设计了一个新的总体布图规划流程。在该流程中,本文对超大型模块的密度计算进行了特殊处理,以减小超大型模块的排斥力,使得其他模块能更加靠近超大型模块,从而实现更加均匀的模块分布。为了更好地利用边框处缝隙中的空白区域,提出了一种边框处缝隙处理方法。最后,在布图规划算法中添加了后处理阶段以进一步优化布图结果。该后处理阶段首先基于混合整数线性规划的翻转模型对模块的翻转方向进行再次优化,然后使用本文提出的新的空白区域再分配方法。该方法减小了线性规划问题中约束条件的数量且能进行多轮次的优化,相对于以往的方法能够更有效地缩短线长。在HB+和ami49_x基准电路上,实验结果表明,本文的布图规划算法与最好的布图规划算法相比,平均半周长线长分别至少减小了13.3%和13.7%。Currently,analytical methods have achieved the best results for VLSI floorplanning.Module flipping has real applications and can further optimize floorplanning results,but analytical methods cannot handle modules flipping in floorplaning.Therefore,this paper attempts to solve this problem by using a unified analytical method,and proposes a new force,i.e.,the flipping force,for modules flipping.The flipping force can guide each module's flipping to its desired direction based on wire length optimization during the global floorplanning stage.In addition,based on the electrostatic field model,this paper designs a new global floorplanning flow in which special treatment is applied to the density calculation of largesize modules.The aim is to reduce the repulsion of these modules and allow other modules to be placed closer to them,thus achieving a more uniform distribution of modules.To better utilize the whitespace between the floorplan boundary and large modules,a gap handling method is proposed.Finally,a postfloorplanning stage is applied to further optimize the floorplanning result.This stage involves reoptimizing the modules flipping directions using a mixedinteger linear programming,followed by applying our proposed new whitespace redistribution method.The whitespace redistribution method reduces the number of constraints in the linear programming problem and allows multiple rounds of optimization,leading to a more effective reduction of wire length compared to previous methods.The experimental results on HB+and ami49_x benchmark circuits show that the proposed floorplanning algorithm achieves an average halfperimeter wire length reduction of at least 13.3%and 13.7%,respectively,compared to stateoftheart floorplanning algorithms.

关 键 词：布图规划 模块翻转 总体布图规划 空白区域再分配 

分 类 号：TN47[电子电信—微电子学与固体电子学]