Auxiliary libraries¶

The Yosys source distribution contains some auxiliary libraries that are bundled with Yosys.

SHA1¶

The files in libs/sha1/ provide a public domain SHA1 implementation written by Steve Reid, Bruce Guenter, and Volker Grabsch. It is used for generating unique names when specializing parameterized modules.

BigInt¶

The files in libs/bigint/ provide a library for performing arithmetic with arbitrary length integers. It is written by Matt McCutchen.

The BigInt library is used for evaluating constant expressions, e.g. using the ConstEval class provided in kernel/consteval.h.

SubCircuit¶

The files in libs/subcircuit provide a library for solving the subcircuit isomorphism problem. It is written by C. Wolf and based on the Ullmann Subgraph Isomorphism Algorithm [Ull76]. It is used by the extract pass (see extract - find subcircuits and replace them with cells).

ezSAT¶

The files in libs/ezsat provide a library for simplifying generating CNF formulas for SAT solvers. It also contains bindings of MiniSAT. The ezSAT library is written by C. Wolf. It is used by the sat pass (see sat - solve a SAT problem in the circuit).