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List:       linux-rt
Subject:    [rtl] Floating Point PROBLEM with RT-Linux
From:       "Estabridis, Janet P" <EstabridisJP () navair ! navy ! mil>
Date:       2000-11-30 21:03:29
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Hi,

I have been going through the mail archives for about 30 minutes.  I have
seem that some people had had problems with floating point random crashes
and did not see a complete resolution.  So, I want to state my case here and
see if someone can help.

I have a Ampro Little Board P5X running at 266MHz with 128MBytes of memory.

1.  I had some old floating point code that was running just fine on
RTLV0.9J (kernel 2.0.36).  It is coded in a timed task (every 30 HZ).

2.  I have changed to miniRTLV2.3 (rtlinux 2.3 with kernel 2.2.14) to embed
my system.  Therefore I had to go to the new API calls.  I do know that I am
turning on floating point properly (I do it in my thread before any floating
point operations).  All my floating point variable are "double" and in the
old shared memory space, except for one local variable.  I read that the
floating point variables should only be initialized after floating point is
turned on.  So I initialize them in the thread after I turn floating point
on.  That works fine.

3.  My development station has Red Hat 5.2 with kernel 2.2.14 and rtlinux
V2.3 so that I could have the correct glibc required for the miniRTLV2.3.  I
complie there and ftp to the embedded machine.


Now, here is the weird part.   The floating point code only get's executed
when a flag is set.  THIS FLAG IS CURRENTLY NOT SET, but When I add back in
the floating point computation code and compile.  When I try to insert the
module hangs the computer it does not return from the insmod.  Now, I can
comment out some of the floating point code recompile and be able to insert
the module and remove the module numerous times.  STILL THIS CODE IS NOT
GETTING EXECUTED IT IS JUST SITTING THERE !!!  

So, what is my potential problem??   Do I have an incompatiblity with my
development station compile ??  I am baffled !!

Any help is GREATLY appreciated.


Janet Estabridis
Electrical Engineer
NAWC Code 472E40D
Building 31440 Room 1017
China Lake, CA 93555
estabridisjp@navair.navy.mil
(760) 939-2896  FAX (760) 939 -3075

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