A mixed mode placement algorithm for combined design of macro blocks and standard cells

A hierarchical automatic placement algorithm for mixed mode placement problems is presented. The so-called mixed mode is a combination of standard cells and macro blocks. The presented algorithm completes the placement at both block level and cell level. In block level, the random cells are firstly partitioned into soft blocks, then a SP (sequence pair) based method (Murata et al, IEEE Trans. CAD, vol. 15, pp. 1518-1524, 1996) is used for block placement. In cell level, firstly, a quadratic placement method is used for inner placement within each soft block, then a placement improvement routine is done to the whole chip, and finally, a combined min-cut and enumeration based detailed placement procedure completes the final placement. The algorithm is tested on a set of circuits with different numbers of standard cells and macro blocks, and obtains satisfactory results.