This document will guide you through the process of installing Yosys.

CAD suite(s)

Yosys is part of the Tabby CAD Suite and the OSS CAD Suite! The easiest way to use yosys is to install the binary software suite, which contains all required dependencies and related tools.

Make sure to get a Tabby CAD Suite Evaluation License if you need features such as industry-grade SystemVerilog and VHDL parsers!

For more information about the difference between Tabby CAD Suite and the OSS CAD Suite, please visit

Many Linux distributions also provide Yosys binaries, some more up to date than others. Check with your package manager!

Targeted architectures

The OSS CAD Suite releases nightly builds for the following architectures:

  • linux-x64 linux-x64
    • Most personal Linux based computers

  • darwin-x64 darwin-x64
    • macOS 12 or later with Intel CPU

  • darwin-arm64 darwin-arm64
    • macOS 12 or later with M1/M2 CPU

  • windows-x64 windows-x64
    • Targeted for Windows 10 and 11

  • linux-arm64 linux-arm64

Building from source

Refer to the readme for the most up-to-date install instructions.

Supported platforms

The following platforms are supported and regularly tested:

  • Linux

  • macOS

Other platforms which may work, but instructions may not be up to date and are not regularly tested:

  • FreeBSD

  • WSL

  • Windows with (e.g.) Cygwin

Build prerequisites

A C++ compiler with C++11 support is required as well as some standard tools such as GNU Flex, GNU Bison, Make and Python. Some additional tools: readline, libffi, Tcl and zlib; are optional but enabled by default (see ENABLE_* settings in Makefile). Graphviz and Xdot are used by the show command to display schematics.

Installing all prerequisites for Ubuntu 20.04:

sudo sudo apt-get install build-essential clang bison flex \
   libreadline-dev gawk tcl-dev libffi-dev git make \
   graphviz xdot pkg-config python3 libboost-system-dev \
   libboost-python-dev libboost-filesystem-dev zlib1g-dev

Installing all prerequisites for macOS 11 (with Homebrew):

brew install bison flex gawk libffi git graphviz \
   pkg-config python3 tcl-tk xdot bash boost-python3

Running the build system

From the root yosys directory, call the following commands:

sudo make install

This will build and then install Yosys, making it available on the command line as yosys. Note that this also downloads, builds, and installs ABC (using yosys-abc as the executable name).

The default compiler is clang, to change between clang and gcc, use one of the following:

make config-clang
make config-gcc

To use a compiler different than the default, use:

make CXX="g++-11"

See also

Refer to Testing Yosys for details on testing Yosys once compiled.

Source tree and build system

The Yosys source tree is organized into the following top-level directories:


This directory contains a subdirectory for each of the backend modules.


Contains the source for this documentation, including images and sample code.


Contains example code for using Yosys with some other tools including a demo of the Yosys Python api, and synthesizing for various toolchains such as Intel and Anlogic.


This directory contains a subdirectory for each of the frontend modules.


Contains developer guidelines, including the code of conduct and coding style guide.


This directory contains all the core functionality of Yosys. This includes the functions and definitions for working with the RTLIL data structures (rtlil.h|cc), the main() function (, the internal framework for generating log messages (log.h|cc), the internal framework for registering and calling passes (register.h|cc), some core commands that are not really passes (,, …) and a couple of other small utility libraries.


Libraries packaged with Yosys builds are contained in this folder. See Auxiliary libraries.


Other miscellany which doesn’t fit anywhere else.


This directory contains a subdirectory for each pass or group of passes. For example as of this writing the directory passes/hierarchy/ contains the code for three passes: hierarchy, submod, and uniquify.


This directory contains simulation models and standard implementations for the cells from the internal cell library.


This directory contains the suite of unit tests and regression tests used by Yosys. See Testing Yosys.

The top-level Makefile includes frontends/*/, passes/*/ and backends/*/ So when extending Yosys it is enough to create a new directory in frontends/, passes/ or backends/ with your sources and a The Yosys kernel automatically detects all commands linked with Yosys. So it is not needed to add additional commands to a central list of commands.

Good starting points for reading example source code to learn how to write passes are passes/opt/ and passes/opt/

See the top-level README file for a quick Getting Started guide and build instructions. The Yosys build is based solely on Makefiles.

Users of the Qt Creator IDE can generate a QT Creator project file using make qtcreator. Users of the Eclipse IDE can use the “Makefile Project with Existing Code” project type in the Eclipse “New Project” dialog (only available after the CDT plugin has been installed) to create an Eclipse project in order to programming extensions to Yosys or just browse the Yosys code base.