HDL libraries are a very powerful feature of the HDL languages. Sigasi makes it easy to configure and use them. In this chapter, we assume that the basic concepts of VHDL libraries are understood. We will explain how they are implemented in Sigasi.

Like with any HDL tool, Sigasi needs to know where the libraries are located on the file system. We will describe how the library configuration can be examined and modified using the GUI.

We will also present some use case about how to set up libraries with Sigasi Studio to organize your projects.

Examining the library configuration

You can examine the library configuration in the libraries and in the explorer view. The Libraries view shows how design units are mapped. The Project Explorer view show how VHDL or Verilog files are mapped.

In the Libraries view you can see a tree of all libraries in your projects. You can open each library to see all contained design units.

In the Project Explorer view each physical file or folder is annotated with the library it belongs to, between square brackets:

What you see here is the initial library mapping of a demo project (you can create such a project by selecting File > New > Other > Demo Vhdl project). We see a project called Demo, with a folder named Common Libraries. In that folder, you see the typical standard libraries (std and ieee) upon which all VHDL projects depend. The demo project itself consists of a few VHDL files.

Next to the project’s name, Demo, is the annotation work. This means that, barring any overrides, everything in the project will be stored inside the work library.

Lower down, we see overrides. For example, the STD folder has an annotation std. This means that, again barring any further overrides, the entire contents of the STD folder will be mapped into the library std. There are no limits to the number of overrides that can be performed. If this needed, any individual file can be mapped to a separate library.

Modifying the library configuration

The library mapping for project files can be modified in the Libraries and Project Explorer view.

Select a file or a folder in the Project Explorer and right-click.

You get a Set Library context menu, with a number of options:

  • Select the name of an existing library to map the file or folder to that library
  • Select Exclude from build to exclude the file or folder from any library
  • Select New Library to define a new library and map the file or folder to it

When you map a file into a library, only that file is affected. However, when you map a folder into a library, then everything in that folder will be mapped into that library. Any overrides in the folder and its sub-folders will be removed. When you are defining the library mapping for a new project you should map from top to bottom.

So in the case of our Demo project, you would change (if work is not a good default) the top folder’s mapping first and then override the mapping in the sub-folders.

When you are changing the library mapping of a project, the project will be rebuilt completely. In order to avoid several consecutive rebuilds while you are setting up your libraries, you can temporarily disable the automatic rebuilds, until you are finished setting up your library mappings. You can do this by disabling the Project > Build Automatically option.

To exclude a file from all libraries, the library mapping context menu provides an Exclude from build option. You can apply that to any file or folder in the project. Sigasi will then assume that the corresponding resource is not a part of the project and will not include that resource in a project build. This is typically useful when you have stale copies of HDL files or folders lying around that you want simply to be ignored.

Configuration file

All library configuration information is stored in the .library_mapping.xml file in the root of your project. If you edit this file, your project will be cleared and rebuilt automatically (a so-called Clean Build).

Sigasi only writes changes to this configuration file when you make changes to the library configuration with the context menu in the Project Explorer. When you do make changes, Sigasi first checks that all paths in the library configuration still exist. If a path no longer exists, is will be removed from the configuration file.

Common libraries

In any newly created VHDL project, the Common Libraries folder contains the VHDL files of the IEEE and STD libraries. This folder is special in the sense that its contents is not stored in regular files on your hard drive. Instead, the files’ contents is shipped as part of the Sigasi installation. Other than that, the Common Libraries folder behaves like any other folder. You can delete it, rename it, and apply a different library mapping. In most cases, however, the default configuration is just what you need.

If you have modified the Common Libraries folder, you can always revert it back to the original state. Right-click on your project in the explorer view and apply menu-entry Reset Library Mapping.

IEEE Vital

See How can I use the IEEE Vital libraries with Sigasi Pro?

Shared libraries

Sigasi allows you to share libraries between multiple projects. The easiest way to do this, is to develop each library in a separate project and configure the Project Dependencies accordingly. To configure the project dependencies, right click the project (the one that uses the shared library) and select Properties. Next click Project References and mark the library project as referenced project.

Using third party libraries

Many projects use third party libraries. These can be added to the project as any other set of VHDL files.

A number of popular third party libraries are the following:

Vendor Library Install dir example
Xilinx unisim C:\Xilinx\14.4\ISE_DS\ISE\vhdl\src\unisims
Xilinx XilinxCoreLib C:\Xilinx\14.4\ISE_DS\ISE\vhdl\src\XilinxCoreLib
Xilinx simprim C:\Xilinx\14.4\ISE_DS\ISE\vhdl\src\simprims
Altera altera_mf C:\altera\12.1\quartus\libraries\vhdl
Mentor modelsim_lib ${ModelSimPath}\vhdl_src\modelsim_lib

On Linux the default installation location for Xilinx is /opt/Xilinx and /opt/altera for Altera.

For many common third party libraries, you can set up the library using a Quickfix for third party libraries.


XilinxCoreLib is a very big library with more than a thousand entities and architectures. If you include all of these design units, it slows down the compilation phase of Sigasi Studio. In order to avoid that, Sigasi Studio only adds the packages with the component declarations to your project by default. It excludes the entities and architectures from compilation.

You can easily add selected entities (and architectures) to your project by right clicking the corresponding file (filename = entity name.vhd) in the Project Explorer, and selecting Set Library > xilinxcorelib.

Library errors from external compilers

If you are using the External Compilers, the external compiler can also put error markers on library clauses. You can easily verify this by checking the prefix of the error message (e.g. vcom: for vcom errors). Consult the Libraries section of the external compiler integration for more information on configuring libraries for your external compiler.