We are motivated by the desires to allow easy mixing of attributes allow for missing attributes reduce storage requirements if many combinations of the same attributes are of interest Therefore, we distribute placement information over several component files. Filenames can be mentioned in an arbitrary order and will be processed in the order relevant for a given multi-file format. The purpose of the placement formats detailed here is to support research and exchange of techniques on fundamental VLSI-CAD problems. Whenever we depart from those formats, this is mainly to ensure additional ease of use or flexibility. Configurations of rows supply constraints for cell placement.
Every row consists of non-overlapping subrows that are aligned at the coordinate of the row.
Subrows can only differ by their origin and the number of sites. In this version of the format all rows are assumed to be horizontal core rows. Additional row types, e.g., vertical pad rows, will be possible in future revisions. The .scl file format is essentially a template, and therefore can be explained using a sample file . This example declares 2 rows - the parser must read 2 rows and ignore whatever follows.