I am looking for a SID emulator that is open source, but not GPL. In particular, I am looking for something with a license that allows me to link it to a closed-source program; and also one that allows me to take its source code and rewrite it in a different language targeting a different platform, and then release that rewrite under an open source license. LGPL, or MIT/BSD would be examples of licenses that would work for me.

I know of the following SID emulator engines, but all of them are GPL:

Then there's also

  • 2
    You could always wrap it in a GPL server which communicates via an open API to your closed source program.
    – Arne
    Jul 8, 2018 at 12:28
  • 2
    Another idea is to ask the programmers if they would re-license it (for a grant) for you.
    – Janka
    Jul 8, 2018 at 18:39
  • 4
    @Arne: that's a can of worms. See gnu.org/licenses/gpl-faq.en.html#AggregateContainers , in particular: But if the semantics of the communication are intimate enough, exchanging complex internal data structures, that too could be a basis to consider the two parts as combined into a larger program. TLDR: Licensing issues are complex.
    – ninjalj
    Jul 9, 2018 at 9:58
  • 2
    I like Janka's idea, for the record. A lot of authors pick the GPL by default for protection while being able to enjoy seeing their code be useful — I'm sure at least one would be happy to relicense to you with a suitable guarantee of credit and references to the GPL original.
    – Tommy
    Jul 9, 2018 at 18:01
  • 1
    GPL does allow you to rewrite it in a different language for a different platform, as long as the rewrite is released under the same license.
    – user253751
    Jul 11, 2018 at 0:32

2 Answers 2


One open source, non-GPL SID emulator that I have found is another one also called jsSID, but completely independent of the one linked in the original question. This one is available from http://hermit.uw.hu/index.php (latest download link) and contains the following license in its README.txt:

Licenses? The license is the popular WTF license, so 'do what the fukk you want with this code'. :) I'd be grateful if my name/credits won't be removed from it, but otherwise feel free to use it as you wish.

The emulator is written in JavaScript and includes its own 6510 emulator as well.

  • There is also a cSID C++ version. But sadly without source code.
    – Arne
    Jul 9, 2018 at 19:40

sid-arduino-lib is LGPL. Its downside is that it is written targeting AVR microcontrollers, so porting it to a desktop setting would be more involved.

  • 7
    Christoph Haberer's original is GPL, not LGPL, so the author claiming their work is LGPL may be a violation of the original licence
    – scruss
    Jul 11, 2018 at 2:27

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .