🔍 nldiff (ALPHA)

A simple utility using Pyverilog that lists the differences between two netlists.

Requirements

• Python 3.8+ with PIP
• IcarusVerilog

Installation

python3 -m pip install --upgrade --no-cache-dir nldiff

Usage

nldiff <first netlist> <second netlist>

Limitations

The tool is designed to operate on netlists coming out of OpenROAD and Yosys. In the interest of expedience, these limitations currently exist:

• Port polarity and widths must be declared inside the module: the module's port argument list must only have the port names.
• Only exactly one netlist allowed per file (flat netlist.)
• Each instance declaration statement must declare exactly one instance: arrays of instances are not allowed and more than one instance in a declaration statement are not allowed.
• Multi-dimensional nets and ports are not supported.

While the previous ones may be addressed in the future, the following will assuredly not:

• Parameters are not supported.
  • wire, input and output widths must be expressed in the form of integer constants and not expressions.
• Assign statements and procedural blocks are not supported.

License

The Apache License, version 2.0. See 'License'.