优化线长和拥挤度的增量式布局算法
Incremental Placement Algorithm for Wirelength and Routability Optimization
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摘要: 随着IC技术的发展,降低连线拥挤度已经成为一个保证布线成功率的至关重要的因素.提出一种标准单元增量式布局算法C-ECOP.该算法通过一个新型的布线估计模型来精确估算布局以后的走线情况,利用力驱动的方法进行单元插入和单元推移来消除局部拥挤,同时进一步优化线长.来自美国工业界的测试实例表明,该算法能够很好地消除走线局部拥挤,同时尽量维持原有布局方案的电路性能,并且具有很高的效率.Abstract: Typical placement objectives involve reducing net-cut cost or minimizing wirelength. Congestion minimization is least studied, however, it models routability most accurately. A new incremental placement algorithm C-ECOP is presented for standard cell layout. The algorithm first estimates the routing congestion through a new route model. Then it minimizes the congestion during inserting and moving cells through force driven. At the same time, it reduces the wirelength. Test cases from industry show that the algorithm can avoid causing congestion during adjusting the placement and preserve the performance of the initial placement with good quality and high speed.
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