I have now got GHDL up and running on my MacBookPro. Getting the Gtkwave tool was at first entertaining.

Now I have been able 'compile' code and in one case run a testbench which looks all ok.

So I am now slowly going through the system and rebuilding the core in GHDL land. Got to stage 5 the execution bit so far.

I had to work out the method of libraries but I've think I've got there now. Having two or more may be interesting.

Once I've got the RTL sorted I need to create the original memories from the Altera memory models. Hopefully this wil be a simple compile but I fear this won't be the case.