On 2014-11-07, Tristan Gingold wrote: > > At this point I wonder if it's not just simpler to just go and > > implement a free alternative implementation instead of discussing > > at length how to handle that IEEE license. I see that it would be > > some work, but the payoff of not having to worry about the licenses > > would be worth it I think. > > Feel free to start the effort. That would be helpful.
I have my own implementation of std_logic_1164 (at VHDL-1993 level). While working on that, I found that it was impossible to get it right without constantly looking at the reference code. There are many places where you appearantly have a choice, and there is no intuitive way to know what the right answer is. For example, to_stdlogicvector always returns an array with range (n-1 downto 0). But to_x01 when working on arrays, always returns an array with range (1 to n). So on the one hand most function bodies are very short and trivial, on the other hand they must give the exact same result as the IEEE reference in every detail. The consequence is that my work is almost textually identical to the IEEE code except for layout and local variable names. It would be easy for the IEEE to claim that my work is a derivative work and therefore subject to their copyright. This is why I believe the clean-room approach is the way to do it. The good news is that I already made an automated testbench to check the behaviour of std_logic_1164 in much detail. And I understand the library well enough to write a detailed specification. So I am ready to play the role of person A. Now I need to find person B: A VHDL programmer who has never looked at the IEEE library files, willing to put in a lot of work to implement according to my specifications. We can start with std_logic_1164, then move on to other libraries. Who is interested? Joris. _______________________________________________ Ghdl-discuss mailing list [email protected] https://mail.gna.org/listinfo/ghdl-discuss
