• The GHDL front-end package std.textio, and the runtime library grt are given under GNU GPLv2.
• The documentation is given under CC-BY-SA.

Warning

As a consequence of the runtime copyright, you are not allowed to distribute an executable produced by GHDL without the VHDL sources. To my mind, this is not a real restriction, since it is pointless to distribute VHDL executable. Please, send a comment (Requesting enhancements) if you don’t like this policy.

• These from library ieee are copyrighted by Institute of Electrical and Electronics Engineers (IEEE) :

• numeric_bit and numeric_std: the source files may be distributed without change, except as permitted by the standard; these may not be sold or distributed for profit. [see also IEEE 1076.3 ]
• std_logic_1164, Math_Real and Math_Complex
• VITAL_Primitives, VITAL_Timing and VITAL_Memory [see also IEEE 1076.4 ]
• The following sources may be used and distributed without restriction, provided that the copyright statements are not removed from the files and that any derivative work contains the copyright notice.

• synopsys directory: std_logic_arith, std_logic_signed, std_logic_unsigned and std_logic_textio are copyrighted by Synopsys, Inc.
• mentor directory: std_logic_arith is copyrighted by Mentor Graphics

## GNU GPLv2¶

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

## CC-BY-SA¶

This is a free documentation; you can redistribute it and/or modify it under the terms of the Creative Commons Attribution-ShareAlike 4.0 license. You are free to share (copy and redistribute the material in any medium or format) and/or adapt (remix, transform, and build upon the material for any purpose, even commercially). We cannot revoke these freedoms as long as you follow the these terms:

• ShareAlike: if you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.
• No additional restrictions: you may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

See CC-BY-SA-4.0 Legal Code for more details.

## List of Contributors¶

Contributor [1] Role
Baggett, Jonas signal selection
Bertram, Felix VPI interface
Davis, Brian Windows Mcode builds
Drummond, Brian GCC 4.8.2 update, OSVVM port, some bugfixes
Gingold, Tristan [2] Sole author of GHDL as a whole
Koch, Markus vendor pre-compile script for Lattice (GNU/Linux)
Koontz, David Mac OSX builds, LRM compliance work, bugfix analyses
Lehmann, Patrick Windows compile scripts, vendor library pre-compile scripts (win+lin), building in MinGW, AppVeyor integration.
Martinez-Corral, Unai Docker builds, Travis-CI & Docker, adapt/fix RTD theme
van Rantwijk, Joris Debian packaging

Only those who made substantial contributions are shown in the table above, but many others contributed with minor patches. You can find a list at

With apologies to anyone who ought to be either on this table or in the GitHub contributor list, but isn’t. Thanks also to all those who have reported bugs and support issues, and often patches and testcases to either the late gna! website or sourceforge.net/p/ghdl-updates/tickets.

Footnotes

 [1] In alphabetical order
 [2] Maintainer