Sorry, forgot to mention, it is tested on bpi-f3, and qemu.

On Mon, May 25, 2026 at 8:21 AM ron minnich <[email protected]> wrote:
>
> OK, some sort of FPU support is "right", in the sense that a single
> program (units and another test) are back to working and giving right
> answers.
>
> I don't want to claim, yet, that it's all solid, i.e., if a process is
> using FPU, and decides to hit its note handler, which uses the FPU,
> and ends up in the kernel, which decides to use the FPU, will all the
> nested traps and restores work correctly? Well, that's to be seen. The
> 9front nested FPU stuff is pretty interesting, took me a while to
> think I understand it, but do I really? Time will tell.
>
> On Sun, May 24, 2026 at 1:01 PM Ron Minnich <[email protected]> wrote:
> >
> > I've tracked the strtod problem to me not getting lazy fpu right, no
> > surprise there :-)
> >
> > On Thu, May 21, 2026 at 1:03 PM ron minnich <[email protected]> wrote:
> > >
> > > some news:
> > > interrupts are working (thanks Shawn Rutledge) and mounting from qemu
> > > vm to a 9front system works as well (thanks José J. Cabezas Castillo).
> > >
> > > We're using listen1 with telnetd atm. We need to test a drawterm in,
> > > although I need to learn how to invoke drawterm such that it will
> > > connect. I see services for all the stuff I'm used to, but not 17010.
> > > But I know 9front improved the situation.
> > >
> > > Lazy FPU support is on, which means nested interrupts had to work, and
> > > they do. Floats seem to work.
> > >
> > > And now to the part I don't understand. strtod on this string:
> > > "2.997925e+8" never returns. This comes up when you run units.
> > >
> > > It is calling frnorm and fpcmp and never seems to converge. I put it
> > > down to something I've fouled up in kernel FPU support, I'm just not
> > > sure what yet.
> > >
> > > strtod does work on several other things ("4.14") but I think the
> > > exponent is tripping it up, but I'm not sure.
> > >
> > > Once this basic stuff is in, we'll want to get bpi-f3 ethernet going.
> > >
> > > Thanks to Jacob Moody and other 9front folks for their encouraging
> > > words. It's meant a lot to us.
> > >
> > > On Thu, May 14, 2026 at 11:01 AM Ron Minnich <[email protected]> wrote:
> > > >
> > > > We continue to clean up the port, and are to the point that we once
> > > > again have ethervirtio10 on qemu, and the same kernel boots on bpi-f3
> > > > and, although the ethervirtio10 is not found, it does not crash :-)
> > > >
> > > > We also continue to "narrow down" the set of differences from 9front,
> > > > and had a great discussion at IWP9 on how to move forward. This time
> > > > around, changes to virtio are quite minimal, and can be dropped once
> > > > we get an interrupt controller working -- at the moment, virtio is
> > > > polled via a clock interrupt (adclock0link ..)
> > > >
> > > > DHCP works fine from the guest.
> > > >
> > > > I have been able, from qemu, to mount 9p, using my "centre" program as
> > > > the 9p server.
> > > >
> > > > Thanks to everyone at IWP9 (and on the video conference) who took the
> > > > time to chat!
> > > >
> > > > On Sun, Apr 26, 2026 at 9:35 PM ron minnich <[email protected]> wrote:
> > > > >
> > > > > one last note: I've cleaned up a lot of the spew that was printing. 
> > > > > From entering the kexec command on the bpi-f3 to a command prompt is 
> > > > > 20s, but I think when I get rid of one last bit of mess (trying to 
> > > > > get entropy) it will be much less time.
> > > > >
> > > > > This iteration is about getting it to work at all, getting it faster 
> > > > > is next.
> > > > >
> > > > > One other person has repro'ed the process on qemu, and it works for 
> > > > > them.
> > > > >
> > > > > ron
> > > > >
> > > > > On Sun, Apr 26, 2026 at 8:06 AM ron minnich <[email protected]> 
> > > > > wrote:
> > > > >>
> > > > >> OK, as of this morning:
> > > > >>
> > > > >> Await             1    0:01   0:10       10K 10       bootrc
> > > > >>
> > > > >> Idle              3    0:00   0:10       13K 0        pager
> > > > >>
> > > > >> Wakeme            5    0:00   0:10       13K 0        alarm
> > > > >>
> > > > >> Pread             7    0:02   0:08       10K 0        paqfs
> > > > >>
> > > > >> Wakeme            9    0:00   0:07       13K 0        closeproc
> > > > >>
> > > > >> Await            12    0:01   0:06       10K 10       rc
> > > > >>
> > > > >> Pread            17    0:00   0:00       10K 0        ps
> > > > >>
> > > > >> on the bpi-f3
> > > > >>
> > > > >>
> > > > >> So the next step is finding some way to get to network
> > > > >>
> > > > >>
> > > > >> Note that the qemu and bpi-f3 continue to behave the same.
> > > > >>
> > > > >>
> > > > >> The more recent fix was, because the 9front kernel is running as 
> > > > >> kexec purgatory, to be sure to zero all the memory we intend to use 
> > > > >> :-)
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> On Sat, Apr 25, 2026 at 9:12 AM ron minnich <[email protected]> 
> > > > >> wrote:
> > > > >>>
> > > > >>> update:
> > > > >>> https://github.com/rminnich/9front/tree/lkg-before-ethervirtio-bpi-f3
> > > > >>> is a bit of a reset. I drove the ron branch off a bridge, I could 
> > > > >>> not make sense of what it was doing on hardware, so I backed out a 
> > > > >>> bit and restarted.
> > > > >>>
> > > > >>> For every change I make, I test on both the bpi-f3 and qemu, since 
> > > > >>> I've learned the hard way it's really easy to break one or the 
> > > > >>> other.
> > > > >>>
> > > > >>> on qemu you do get to an rc prompt.
> > > > >>>
> > > > >>> On bpi-f3, the exec in initcode fails. The second argument is -1, 
> > > > >>> instead of a proper pointer. Tracking register values, all looks 
> > > > >>> ok. But ...
> > > > >>>
> > > > >>> There seems to be *something* scribbling on the stack page on the 
> > > > >>> bpi-f3. That's as far as I've gotten.
> > > > >>>
> > > > >>> But, I've fixed a few issues that come up when kexec 9qemu, such as 
> > > > >>> the need in main() to zero bss explicitly, since kexec does not 
> > > > >>> know where bss is.
> > > > >>>
> > > > >>> Getting there. There is one other person testing on qemu, who has 
> > > > >>> reported some success, so that is a bit of good news.
> > > > >>>
> > > > >>> On Tue, Apr 21, 2026 at 9:19 PM ron minnich <[email protected]> 
> > > > >>> wrote:
> > > > >>>>
> > > > >>>> yes, bpi-f3 has been a good target for me to work with. Right now, 
> > > > >>>> I'm hitting a weird problem, but qemu and the bpi-f3 behave 
> > > > >>>> identically, which is helpful.
> > > > >>>>
> > > > >>>> as to stimecmp, it's there and I've no idea what genode is talking 
> > > > >>>> about.
> > > > >>>>
> > > > >>>> On Tue, Apr 21, 2026 at 7:07 PM Frank D. Engel, Jr. 
> > > > >>>> <[email protected]> wrote:
> > > > >>>>>
> > > > >>>>> That article appears to be fairly old; apparently from somewhere 
> > > > >>>>> around
> > > > >>>>> 2016 if I am reading it correctly?
> > > > >>>>>
> > > > >>>>> Going by the official RISC-V documentation site
> > > > >>>>> (https://docs.riscv.org/reference/isa/priv/sstc.html) it looks 
> > > > >>>>> like what
> > > > >>>>> they did was left MTIMECMP in the core architecture and moved 
> > > > >>>>> STIMECMP
> > > > >>>>> to an extension which makes it optional for processors to 
> > > > >>>>> implement.
> > > > >>>>>
> > > > >>>>>
> > > > >>>>>
> > > > >>>>> On 4/21/26 16:21, Dave Eckhardt wrote:
> > > > >>>>> >> Things like the STIMECMP were a major improvement and I don't 
> > > > >>>>> >> want
> > > > >>>>> >> to work without them.
> > > > >>>>> > Given a strong endorsement like that, and knowing very little 
> > > > >>>>> > about
> > > > >>>>> > RISC-V, I figured maybe it would be good to read up on STIMECMP.
> > > > >>>>> >
> > > > >>>>> > One of the first things I found was this:
> > > > >>>>> >
> > > > >>>>> > https://genode.org/documentation/articles/riscv#Timer
> > > > >>>>> >
> > > > >>>>> > ...which appears to be a claim that STIMECMP is already 
> > > > >>>>> > deprecated,
> > > > >>>>> > or am I misreading it?
> > > > >>>>> >
> > > > >>>>> > Dave Eckhardt
> > > > >
> > > > > 9fans / 9fans / see discussions + participants + delivery options 
> > > > > Permalink

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