Quadratic Programming Based Standard-cell Placement with New Additional Force

새로운 부가 힘을 사용한 Quadratic Programming 기반의 표준셀 배치

  • Published : 2002.06.01

Abstract

This paper deals with a standard cell placement which is based on a quadratic programming. This paper proposes a new additional force to reduce the cell overlap and to get a uniform distribution of cells. The additional force is not concerned with interconnections between cells, but it is determined by the density of a placement area. In this paper, we modelled that the new additional force is a force which is caused by the dummy fixed cell. And it is used for the global placement. Proposed placement method is compared with TimberWolf v7.0 and Itools vl.4. Proposed placer achieved 7.5% average reduction in wirelength in non timing driven mode, 5.0% average reduction in wlrelength in timing driven mode compared to TimberWolf v7.0. And we got a comparable result to Itools vl.4.

본 논문은 quadratic programming(QP) 기반의 표준셀 배치에 대하여 다룬다. 본 논문은 QP 기반의 배치에서 발생하는 셀겹침을 제거하고 균등한 배치를 얻기 위하여 새로운 모델의 부가 힘을 제안한다 부가 힘(additional force)이란, 셀 사이의 연결과는 관계없이 배치영역 내의 셀의 분포 밀도에 의해 받게되는 힘을 의미한다. 본 논문에서는 부가 힘을 가상 고정셀(dummy fixed cell)에 의해 발생되는 힘으로 모델화하여 그것을 이용한 개략배치 방법을 제안한다. 제안한 배치방법에 의한 최종 배치결과를 TimberWolf v7.0과 Itools vl.4와 비교하였다. 제안된 배치기는 시간지연을 고려하지 않은 경우, 배선거리에서 TimberWolf v7.0에 비하여 평균 7.5% 향상된 결과를 얻었다. 시간지연을 고려했을 경우, 배선거리에서 Timberwolf v7.0에 비하여 평균 5.0% 향상된 결과를 얻었다. 그리고 Itools vl.4에는 비교할만한 결과를 얻었다.

Keywords

References

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