Soft Float for PC386

[angelo]

Successfully built and ran by modifying the following in pc386.cfg

ifeq ($(RTEMS_CPU_MODEL),)
RTEMS_CPU_MODEL=i386_nofp
CPU_CFLAGS =-msoft-float
endif

I am not sure whether I should add the -mno-fp-ret-in-387 to the CPU_CFLAGS, I
have tried both with the same result.

The target now runs in the PC, however, when I attempt to run the paranoia.exe
,I get the following error message

*** PARANOIA TEST***
Exception 7 caught at PC 10743 by thread 13428265
processor execution context at time of the fault was
EAX = 0     EBX = 134300    ECX = 0    EDX = 0
ESI = 13414    EDI = 12D878    EBP = 1342A8    ESP = 134268

Error code pushed by processor itself (if not 0) = 0
****************   FAULTY THREAD WILL NOW BE DELETED ********************


I then did a PC 586 build (even with an unmodified pc386.cfg) and tried to run
paranoia on a Pentium 100 and got this huge message about 4 errors being found.
These tests have been done with snapshots rtems-ss-20010109 and
rtems-ss-20010126.  Has anyone else tested paranoia.exe on a PC lately and found
the same problem?

Joel Sherrill wrote:

> angelo wrote:
> >
> > I have successfully run  RTEMS apps on a Pentium using the pc386 build,
> > however, when I attempt to run the apps (including the hello world ) on a
> > 386 with no co-processor, The console just display an infinite Exception
> > which I cannot read.
>
> Hmmm.. I would be surprised if the lack of an FPU is causing this.  But
> stranger things have happened over the years.  What RTEMS version are
> you trying?  It might also be worth it to put a "while 1" loop in the
> exception handler temporarily so the message won't disappear.
>
> > I suspect that it may be that soft float is required,
> > but I am not sure.  Is there a way of ensuring that I am not trying to use
> > the co-processor and am in fact using the soft floating point libraries.
>
> The answer is simple and not so simple at the same time.  The standard
> gcc sources do not have soft-float support turned on for the i386 targets.
> The RTEMS gcc patches and RPMs post 4.5.0 do include support for this.
>
> If you look at the ts_386ex target in recent snapshots, its CPU_CFLAGS
> should be the basis for adding a new pc386 variant (like pc[56]86 and
> pck6).  Right now all pc386 variants assume an FPU.
>
> > --
> > Angelo Fraietta
> >
> > PO Box 859
> > Hamilton NSW 2303
> >
> > Home Page
> >
> > http://users.hunterlink.net.au/~maaaf/
> >
> > There are those who seek knowledge for the sake of knowledge - that is
> > CURIOSITY
> > There are those who seek knowledge to be known by others - that is VANITY
> > There are those who seek knowledge in order to serve - that is LOVE
> >     Bernard of Clairvaux (1090 - 1153)
>
> --
> Joel Sherrill, Ph.D.             Director of Research & Development
> joel at OARcorp.com                 On-Line Applications Research
> Ask me about RTEMS: a free RTOS  Huntsville AL 35805
> Support Available                (256) 722-9985

--
Angelo Fraietta

PO Box 859
Hamilton NSW 2303

Home Page

http://users.hunterlink.net.au/~maaaf/

There are those who seek knowledge for the sake of knowledge - that is CURIOSITY

There are those who seek knowledge to be known by others - that is VANITY
There are those who seek knowledge in order to serve - that is LOVE
    Bernard of Clairvaux (1090 - 1153)