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Am I allowed to release a RISC-V implementation (written in VHDL or Verilog) under the GPL-v3? If so, what additional "credit", etc. do I have to give?

The FAQ on the RISC-V site says that the ISA spec is licensed with a BSD license, but the BSD license is specific in talking about licensing source code and binaries, so I don't understand how they are applying it.

Can anyone explain how their licensing works and point me to a link on the website that actually has the license?

Leonhart231
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  • Would whoever gave a -1 mind explaining? Since my question is about the licensing of a program, I _believe_ it is within the rules here as it is "unique to software development". – Leonhart231 Feb 06 '16 at 23:28

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You can do whatever you want with your implementation, including keeping it closed source and selling it.

If you're going the open-source route and don't want to use BSD, then I personally recommend you look into the CERN Open Hardware License, and listen to the licensing talk from the 2015 ORCONF conference that took place at CERN. GPL was not written for hardware and may not properly protect you or your work.

The FAQ on the RISC-V site says that the ISA spec is licensed with a BSD license, but the BSD license is specific in talking about licensing source code and binaries, so I don't understand how they are applying it.

That's a great question for a lawyer. Even if the RISC-V Foundation is using the wrong license, their intention is clear - anybody can implement the ISA and do whatever they want with their implementations and the Foundation will not come after you.

Chris
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  • "Their intention is clear - anybody can implement the ISA and do whatever they want with their implementations and the Foundation will not come after you." That was my general understanding too, but it's good to get a second set of eyes to check. Thank you. I should have worded more carefully, but since I'm licensing the code itself (even though it generates hardware), the GPL does protect just fine. That being said, I will certainly look into the CERN license as well so I can make the right decision. – Leonhart231 Feb 08 '16 at 04:16
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I believe the answer is yes. The BSD license refers to the spec (an interface described in a document), not to your implementation.

user2548418
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  • The RISC-V Instruction Set Manual - http://www.eecs.berkeley.edu/Pubs/TechRpts/2014/EECS-2014-54.pdf is not BSD, it is Copyrighted and allowed to personal and classroom use only. Other uses and redistribution require permission. BSD license was declared only to reference implementations of RISC-V: Rocket and Sodor; and on some software tools, like Spike. IIT cores may be BSD-licensed too: https://www.eecs.berkeley.edu/Pubs/TechRpts/2014/EECS-2014-146.pdf – osgx Mar 13 '16 at 21:48
  • @osgx Years later: unprivileged spec 2.1 and privileged spec 1.9.1 (2016) were released by the authors under CC-BY 4.0, and current versions indicate they are under that license as well. – Alex Shpilkin Dec 27 '22 at 15:37
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You can, but your fork will be boycotted by a significant number of people - including myself. Please use a permissive license approved by copyfree.org, and then everyone will be able to use and contribute to your project.

libman
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