[J-core] Porting J1 to LiteX

[Rob Landley]

On 6/15/21 10:36 PM, William D. Jones wrote:
>  >Yup.  GMail is becoming unusable for business also.  It's now blocking 
> anything with 'investment' or other often 'misused' business and 
> financial terms etc.  Useless.
> 
> Today I added SPF, DMARC, and DKIM. GMail (and Microsoft!) is still 
> blocking my messages. I guess we'll have to wait and see...
> 
>  >Ok, I'll have a look, thanks :)
> 
> If my changes get accept back to the main repo, would you consider 
> making jcore-j1-ghdlcapable of supporting CPU variants (no cache, 
> icache, icache/dcache, multi-cycle multiplier)? VHDL doesn't seem to 
> have an equivalent of Verilog `ifdef, so conditional compilation for 
> variants seem more difficult.

It has its own syntax, something called "configurations":

  https://github.com/j-core/jcore-cpu/blob/master/core/cpu_config.vhd

That's the bit I don't understand yet, which we need to add more of to wire up
the parts that diverge between ice40 and xilinx into a common repo. (It's like
15 minutes of Jeff explaining it to me in person, but he had to leave Tokyo
right before we got to that bit and I flew back to Austin a few weeks later, and
we've been in our respective countries ever since. We've experimented with "voip
call and ssh -x screen sharing" and it's better than nothing, but not by much.)

>  >Hmmm.  IMHO don't do that, just merge them in the wrapper. Far less logic.

I do not seem to have gotten the email you're replying to here. (Nor does the
web archive...)

Rob