SPFD-based effective one-to-many rewiring (OMR) for delay reduction of LUT-based FPGA circuits
SPFD-based effective one-to-many rewiring (OMR) for delay reduction of LUT-based FPGA circuits
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DOI：
10.1145/988952.989037
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发表时间：
2004-04
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影响因子：
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通讯作者：
Katsunori Tanaka;S. Yamashita;Y. Kambayashi
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文献类型：
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作者：
Katsunori Tanaka;S. Yamashita;Y. Kambayashi
本文提出了一种基于查找表的FPGA电路中基于SPFD重布线的新方法。新方法将新的输入线添加到两个或更多个LUT，以便移除或替换目标线。到目前为止，FPGA电路已经有一些重新布线的方法，例如最初的基于SPFD的优化，有时称为局部重新布线（LR），基于SPFD的全局重新布线（GR）和基于SPFD的增强重新布线（ER）。然而，所有这些都用到一个LUT的其他新输入线来替换一条线，而不是用到两个或更多LUT的那些新输入线。此外，LR仅将输入线移除或用新的输入线替换到同一LUT，并且GR和ER在拓扑上限制添加新输入线的LUT。我们的新方法，称为一对多重布线（OMR），放松这样的拓扑约束，更灵活的FPGA电路变换，使它更容易导入物理设计的约束，逻辑优化。实验结果表明，通过引入新的操作方法--线加法，我们的OMR可以比LR、GR和ER更灵活地对FPGA电路进行变换。OMR的换线能力是现有方法的1.2倍，尤其是ER。计算时间与现有方法一样短。
This paper proposes an innovative method for SPFD-based rewiring in Look-Up-Table-based (LUT-based) FPGA circuits. The new method adds new input wires to two or more LUT's in order to remove or to replace a target wire. There have been a few rewiring methods for FPGA circuits so far, such as the original SPFD-based optimization sometimes called Local Rewiring (LR), SPFD-based Global Rewiring (GR) and SPFD-based Enhanced Rewiring (ER). However, all of them replace one wire with other new input wire to one LUT but not with those to two or more LUT's. Moreover, the LR removes or replaces input wires with new one to the same LUT only, and the GR and ER topologically limit the LUT's where new input wires are added. Our new method, called One-to-Many Rewiring (OMR), loosens such topological constraints for more flexible FPGA circuit transformation so that it is easier to import constraints on physical design to the logic optimization. The experimental results show our OMR can transform FPGA circuits more flexibly than the LR, GR and ER, by introducing the new manipulation, wire addition. The OMR can rewire 1.2 times as many wires as the existing methods, especially, the ER. The computation time is as short as the existing methods.