Post by John H. Reinhardt
I don't know of anyone doing the VAX architecture in a FPGA.
One of the most popular (and best) PDP-11 implementation in FPGA is the PDP2011 project of Sytse van Slooten at https://pdp2011.sytse.net/wordpress/
W11 - <https://wfjm.github.io/home/w11/>
POP11 - <http://labo.nshimizu.com/pop11.html>
Verilog PDP-11 - <http://www.heeltoe.com/download/pdp11/README.html>
Some haven't been active in a while. The PDP2011 project is active and Sytse is always working on improvements.
I wasn't even aware of the Verilog PDP-11, so you've inspred me to update my
webpage with links.
I thought that Tokai University had done a VAX-11/780 implementation, in
addition to the PDP-11 one you mention above. However, using Archive.org,
it looks like I may have been premature on listing that. They were
apparently at least working on it 15+ years ago.
I also have a line on the FPGA page that says "RT Logic" was reimplementing
the VAX in FPGA for HP, but the link is understandably dead.
Since the OP mentioned Twenex...