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From: projoe@crim.eecs.umich.edu (Joseph A. Dionise)
Newsgroups: comp.realtime
Subject: Re: Shared memory with multiple processors running VxWorks
Keywords: VxWorks/multiple processors/ shared memory
Message-ID: <347@zip.eecs.umich.edu>
Date: 14 Sep 89 22:03:04 GMT
References: <4252@ncar.ucar.edu> <6143@pt.cs.cmu.edu>
Sender: news@zippy.eecs.umich.edu
Reply-To: projoe@crim.eecs.umich.edu.UUCP (Joseph A. Dionise)
Organization: University of Michigan EECS Dept., Ann Arbor, MI
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In article <6143@pt.cs.cmu.edu> hmp@cive.ri.cmu.edu (Henning Pangels) writes:
>
>	Rather than mucking around with the sysLib routines, I modified the
>Makefile and usrConfig.c used to build VxWorks. In the Makefile, I define
>USER_CFLAGS = -DRESERVE_MEM=0x100000, which is appended to the regular
>CFLAGS. Then, in usrConfig.c, I change the kernel initialization ...
>

   I agree.  This method is better than the approach that I outlined.
   
>
>As an aside: Be careful about mapping several processor's memory spaces
>contiguously -- some versions of the sysMemTop() routines work by probing
>for live memory, so if there's no memory gap between boards, one processor
>might actually claim another's memory for itself.
>

   We encountered this problem.  In fact, this is why I initially modified
the sysMemTop() routine.  I hard coded it to return the amount of onboard 
RAM, instead of probing for the first "open" byte.  

The moral to this story : become familiar with the sysLib library.  It is
the gateway to your processor.


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#  Joseph A. Dionise                                                           #
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