MVME3100 FPU Support on RTEMS 4.10.2

[Joel Sherrill]

On Wed, Jun 6, 2018, 4:29 PM Michael Davidsaver <mdavidsaver at gmail.com>
wrote:

> On 06/06/2018 02:24 PM, Matt Rippa 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.
>
> Last I checked (~5 years ago) the newer mvme2500 had a price similar to
> the mvme3100.
> The issue was software support.  At the time there didn't seem to be RTEMS
> board
> support
>


I would expect the mvme2500 to just one of the many variants supported by
the motorola_powerpc BSP family. Some of the board variants, you could just
use another variant name. I don't know if this would require tweaks or not.

What about the mvme5500? It wasn't mentioned by anyone. Is that a price
issue?

I suppose spinning off Motorola Computing Group and the processor group has
resulted in few upgrade options.


>
> > 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 <mailto: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
> <
> 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
> >     >
> >
> >
> >
> >
> > --
> >
> _______________________________________________
> users mailing list
> users at rtems.org
> http://lists.rtems.org/mailman/listinfo/users
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.rtems.org/pipermail/users/attachments/20180606/737cc1f6/attachment-0002.html>