MVME3100 FPU Support on RTEMS 4.10.2

[Joel Sherrill]

On Thu, Jun 7, 2018 at 8:26 AM, Gedare Bloom <gedare at rtems.org> wrote:

> On Wed, Jun 6, 2018 at 10:35 PM, Heinz Junkes <junkes at fhi-berlin.mpg.de>
> wrote:
> > There is RTEMS 5 support for the MVME2500 made by Sebastian Huber.
> > Unfortunately, I have not been able to test it properly with EPICS7.
> > I will try it after the Epics meeting and will report.
> >
>
> The BSP support for mvme2500 is in the qoriq family of powerpc BSPs. I
> have no clue how difficult it would be to use with 4.10. The APU route
> suggested by Till is probably ideal unless you need 'double' types...
>

If you want to use that BSP, I recommend upgrading RTEMS. There are
a lot of differences between 4.10 and the master including SMP, BSP
infrastructure improvement, and even qoriq support itself.

I think it would be much less work to update RTEMS than to backport
the BSP.

--joel


>
> Gedare
>
> > Heinz
> >
> >> On 6. Jun 2018, at 23:24, Matt Rippa <mrippa at gemini.edu> wrote:
> >>
> >> Thanks for the fast reply. Of all the mvme boards you listed,
> >> the 3100 hits a nice price point and we're attempting to find
> >> suitable replacement stock (quantity 30+) for the 2700 which are no
> longer
> >> manufactured.
> >>
> >> Are the 6100 boards on beatnik bsp the only remaining option for RTEMS?
> >> They cost nearly twice as much and have shown thermal regulation issues.
> >>
> >> -Matt
> >>
> >> On Wed, Jun 6, 2018 at 11:10 AM, Michael Davidsaver <
> mdavidsaver at ospreydcs.com> wrote:
> >> Hi Matt,
> >>
> >> The MVME3100 is based on the MPC8540 processor.  This chip doesn't have
> an FPU.
> >> Other boards do (eg. mvme270x, mvme6100, or mvme2500) and RTEMS
> supports this.
> >>
> >> I can certainly confirm that lack of an FPU really hurts performance,
> even
> >> something as (apparently) simple as integer to float.
> >>
> >> Michael
> >>
> >>
> >> On 06/06/2018 02:03 PM, Matt Rippa wrote:
> >> > It appears we've compiled our mvme3100 bsp without FPU support.
> >> > We're on the mvme3100 running EPICS 3.14.12.7 and RTEMS 4.10.2.
> >> >
> >> > We're attempting to commission our astrometric kernel control system
> >> > and we've run into trouble meeting some of our thread deadlines. What
> >> > we've found is a transform routine that takes our mvme2700 ~200 us,
> >> > takes the mvme3100 ~8 ms.  So not a surprise to see this with only
> "-msoft-float"?
> >> >
> >> > ...
> >> > 2018-05-31-tcs.log:May 31 11:41:15  E) PORT: tcs_vme, MSG: Welcome to
> rtems-4.10.2(PowerPC/Generic (*no FPU*)/mvme3100)
> >> >
> >> > Is FPU support possible with RTEMS 4.10.2? If so, what would we need
> to do?
> >> > It looks like there's a multilib on 4.11.2 https://docs.rtems.org/
> releases/rtems-docs-4.11.2/cpu-supplement/powerpc.html#multilibs(*Eg.,
> see #13* )
> >> >
> >> > Here's our bsp specs:
> >> >
> >> > beatnik:
> >> > -specs bsp_specs -qrtems -fasm -c -mcpu=7400 -D__ppc_generic -DUNIX
> -O2 -g -g -Wall
> >> > (mvme2700) mvme-2307:
> >> > -specs bsp_specs -qrtems -fasm -c -mcpu=604 -mmultiple -mstring
> -mstrict-align -meabi -DUNIX -O2 -g -g -Wall
> >> > mvme-3100
> >> > -specs bsp_specs -qrtems -fasm -c -mcpu=powerpc *-msoft-float*
> -D__ppc_generic -DUNIX -O2 -g -g -Wall
> >> >
> >> > Thank you!
> >> > -Matt
> >> >
> >>
> >>
> >>
> >> --
> >>
> >> ----------------------------------------------------------------------
> >> Das FHI verarbeitet, speichert und loescht Daten im Rahmen seiner
> >> Geschaeftstaetigkeit gemaess der Datenschutz-Grundverordnung (DSGVO)
> >> [General Data Protection Regulation (GDPR)] der Europaeischen Union.
> >>
> >
> >
> > ----------------------------------------------------------------------
> > Das FHI verarbeitet, speichert und loescht Daten im Rahmen seiner
> > Geschaeftstaetigkeit gemaess der Datenschutz-Grundverordnung (DSGVO)
> > [General Data Protection Regulation (GDPR)] der Europaeischen Union.
> >
> >
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