[libre-riscv-dev] div pipe

[Jacob Lifshay]

On Sun, Jul 19, 2020, 14:12 Luke Kenneth Casson Leighton <lkcl at lkcl.net>
wrote:

> btw jacob i'm aware i did exactly the same thing to the ieee754 div pipe! i
> did try running the div core unit tests, they weren't working.  i didn't
> understand how to fix them so i proceeded anyway.


DivPipeCore broke because you forgot (or didn't know) to account for the
changing number of fractional bits when you changed the bit width for
supported={UDivRem}

I was working on fixing that but gave up since I'm planning on using the
FSM instead for the oct tapeout, and I'm planning on rewriting the div
pipeline to add dynamic partitioning and loop-back for the 28nm tapeout, so
the current div pipe core won't be needed. What we could do is just revert
the bitwidth changes if we want to have working code anyway.

Jacob