matchports.py

py/matchports.py

Renumbers a magic cell’s port indices so the extracted netlist’s pin order matches a reference netlist.

make matchports                      # dry run, from work/
make matchports MPOPT=--apply        # write

python3 ../tech/py/matchports.py --mag ../design/<LIB>/<CELL>.mag \
                                 --ref cdl/<CELL>.spice --apply

Option	Default	Meaning
--mag	required	Layout .mag to renumber
--ref	required	Netlist whose .subckt order to match
--cell	.mag basename	Subcircuit name to look for
--apply / --dry-run	dry run	Write the file

Why

ext2spice orders the .subckt pin list by the port N indices stored in the .mag, not by label position or name. When a layout is built, or its ports are relabelled, those indices often end up in a different order than the schematic. LVS still passes, because netgen matches pins by name, but the two netlists are then awkward to diff and any tool that assumes a fixed pin order gets it wrong.

What it changes

Only the numbers on port N lines inside << labels >>. Geometry, layers, labels and net names are untouched. Ports are ordered as they appear in the reference; ports that exist in the layout but not in the reference keep their relative order and are pushed to the end, marked [not in ref -> end] in the report. Names in the reference that are missing from the layout are warned about in yellow.

Re-extract afterwards (make lvs) to pick up the new order, and reload the cell if magic has it open.