HBS is a Tcl-based, minimal common abstraction build system for hardware design projects.

If you find HBS useful, and write any academic publication on a project utilizing HBS please consider citing.

@Article{electronics15153292,
  AUTHOR = {Kruszewski, Michał},
  TITLE = {Characterizing and Comparing Direct-Tcl and Indirect-Abstract Approaches for Hardware Build Systems},
  JOURNAL = {Electronics},
  VOLUME = {15},
  YEAR = {2026},
  NUMBER = {15},
  ARTICLE-NUMBER = {3292},
  URL = {https://www.mdpi.com/2079-9292/15/15/3292},
  ISSN = {2079-9292},
  DOI = {10.3390/electronics15153292}
}

Please check the official HBS user manual. There is also the article (Characterizing and Comparing Direct-Tcl and Indirect-Abstract Approaches for Hardware Build Systems) explaining why HBS was designed in such a way and how it compares to other hardware build systems.

• ghdl,
• gowin,
• modelsim - set tool to questa,
• nvc,
• quartus,
• questa,
• vivado-prj - Vivado project mode,
• xsim - Vivado simulator.

• Running testbench subprocesses when hbs is not in PATH.

• Support for Quartus.
• Optional doc (core documentation) parameter to the hbs::Register procedure.
• doc command for viewing cores documentation.
• dump command to dump cores in Tcl dictionary format.

• Hbs files are sourced as soon as they are found, not after scanning all subdirectories first.
• Vivado: Treat .tcl files as constraint files by default.
• Rename doc command to info.
• Rename whereis command to where.
• Rename dump-cores command to dump-json.
• Rename list-cores command to ls-cores.
• Rename list-targets command to ls-targets.
• Rename list-tb command to ls-tb.
• Rename ArgsPrefix to ArgPrefix.
• Rename ArgsSuffix to ArgSuffix.
• Rename CoreDir procedure to ThisCoreDir.
• All the logic is now implemented in the single Tcl file, no Python required anymore.

• Enforcing tool via HBS_TOOL environment variable calls tool custom setTool procedure.
• JSON dump path for gowin in dry run.

• dry-run command for dry run and previewing commands.
• Questa simulator support.
• HBS_DEBUG environment variable for debugging prints.
• HBS_DEVICE environment variable for enforcing device.
• HBS_EXIT_SEVERITY environment variable for enforcing exit severity.
• HBS_BUILD_DIR environment variable for enforcing build directory.
• HBS_TOOL environment variable for enforcing tool.
• HBS_STD environment variable for enforcing HDL standard revision.
• -onerror quit argument for xsim.
• hbs::ExitSeverity variable for unifying exit condition in simulators.

• Improved error messages.
• Improved regex for errors and warnings.
• vivado-prj: Part is set immediately as hbs::SetDevice is called.
• vivado-prj: Bitstream file name changed from current project name to hbs::Top. This is required for write_hw_platform -include_bit command to work without any extra actions.
• Rename TopCore and TopTarget to RunCore and RunTarget.
• Rename targetDir to RunTargetBuildDir and make it public.

• Generics handling for xsim.
• test command returns an error if any test fails.