overhaul was to introduce the concept of a "connection point"
between two cells to the ".ext" file format so that it becomes
possible to do proper hierarchical R-C extraction. Previously
this information was not kept in the .ext file, making it
impossible for "extresist" to know what sub-net of a net connects
up or down the hierarchy. However, additional changes were made
to the extresist code (in the resis/ directory) to add the
handling of connections up and down the hierarchy, and to make
the code a lot clearer and fix ambiguous variable and subroutine
names.
"extresist" command continues to work as before. However, the
method now reads from .ext files instead of .sim files, so
generating ".sim" and ".nodes" files is no longer necessary.
In addition, the core code of "extresist" was put directly into
ExtCell.c so that full R-C extraction can be run using
"extract do resistance" followed by "extract all", without
needing to run "extresist" at all other than to set parameters
(e.g., "extresist tolerance 10").
R. Timothy Edwards