netlist-carpentry 0.2.0

A library for netlist modification and analysis

Netlist Carpentry

Netlist Carpentry is a Python library that allows you to access and modify a digital circuit in an accessible way. It covers the following use cases:

• Navigate through your circuit and introduce custom checks
• Implement new algorithms that do optimizations or modifications with your circuit
• ...

It uses Yosys to get the circuit from a behavioral code and converts it into a pythonic structure along with a networkx graph. This allows for using standard graph algorithms on the circuit as well as pretty-printing facilities.

Once in Python, the structure can be examined and modified. Netlist carpentry internally tracks all the changes and lets you write out your modified circuit to Verilog. Back in verilog, the most simulation or synthesis tools can be used.

A simple example:

import netlist_carpentry

# Load your Circuit
circuit = netlist_carpentry.read("simpleAdder.v")
# Define your top module
circuit.set_top('simpleAdder')

print(f"The top module '{top_module.name}' has the following items:")
for instance_name, instance_object in top_module.instances.items():
    print(f"\tInstance '{instance_name}'.")

for port_name, port_object in top_module.ports.items():
    print(f"\tPort '{port_name}', which is an {port_object.direction} port and {port_object.width} bit wide!")

for wire_name, wire_object in top_module.wires.items():
    print(f"\tWire '{wire_name}', which is {wire_object.width} bit wide!")

Netlist Carpentry is designed for making the access to the circuit as easy as possible. The runtime-performance was not always in focus -- so don't expect it to work as fast as a custom-knitted C++ software. If you want to propose changes, please submit an issue or even a pull request.

Installation

Install the package via...

pip install netlist-carpentry

... and have fun!

The package requires at least Python 3.9 (recommended is 3.12).

Alternatively, you can clone this repository and install the package in editable mode.

Examples

Examples on how to use Netlist Carpentry (and how it can be integrated into design workflows) can be found in docs/src/user_guide along with the documentation. Most of them are Jupyter Notebooks, meaning they can be executed and modified to experiment with Netlist Carpentry. They can also be viewed in the online documentation.

Development Guide

A guide on how to expand or modify the tool is also given. Visit docs/src/dev_guide or the online development guide for more information.

Acknowledgement

The DI-Meta-X project where this software has been developed is funded by the German Federal Ministry of Research, Technology and Space under the reference 16ME0976. Responsibility for the content of this publication lies with the author.