[kevmo314]

The difficult part is the place and route algorithm, not the bitstream. The proprietary ones already take quite a long time to solve: I regularly have 12-24h runs. Perhaps an open source one could do better? But it's not quite as straightforward as reverse engineering a proprietary bitstream.

[javawizard]

That's why nextpnr exists :)

https://github.com/YosysHQ/nextpnr

As someone actively working on nextpnr support for a fairly new FPGA architecture, it really is amazing that we have something like that in the open source world.

YosysHQ are one of my favorite companies to exist.

[epsilon537]

Nextpnr and Project X-Ray are amazing projects. Reverse engineering the physical map of, say, a 7-series FPGA is no small feat. However, I wonder if they'll ever be able to really compete with Vivado without getting access to the characterization models for timing. I would love to switch over, but the Fmax of my project routed with nextpnr is less than half of what I get with Vivado.

[Taniwha]

When I first started doing chip design my boss paid more for tools per year than he paid me ... now days open source tool chains are leaping ahead ... I don't need a boss (or VCs) in order to design chips

[ginko]

I have to admit that I haven't looked too closely into this but my understanding is that place & route is essentially an NP hard optimization problem. Would it be possible to translate this into a SAT problem and solve it with a state of the art SAT solver?

[kevmo314]

It's surely possible but if it's, for example, 10% slower, that easily eats into execution time and that directly translates into a sense of "maybe it's just worth it to pay the license fee for this year" after just a few 20h place and route runs.

Of course, if it were faster, that would be a huge win for the open source implementation.

[rowanG077]

Possible but the problem statement is generally way too large to throw into a SAT solver. You can do local problems with SAT though.

[FarmerPotato]

Somewhere in reverse-engineering-land is the desire to figure out undocumented hardware blocks. I’m not disagreeing about PNR here.