[En-Nut-Discussion] En-Nut-Discussion Digest, Vol 56, Issue 7

[steve]

Hello again,

  The problem was stack overflow - IJG uses 2-3K of stack space and NutOs
  allocates only 768B for the main() thread.  I put the code in a new thread
  with 3K of stack space and the problem went away.

  Maybe this will be helpful to someone else.

Best Regards,
Steve.

At 11:00 12/06/2008, you wrote:

>Hi,
>
>   I'm trying to use Ethernut (on a SAM7X256-EK) with IJG's jpeg
>   decompression code (ijg.org).  It kind of works but the process of
>   decompressing a very small 16x16 pixel test image, which does generate
>   the correct output, screws up NutNet in such a way that any subsequent
>   call to NutUdpReceiveFrom or NutUdpSendTo immediately crashes
>   the processor without an error message.  At the point just prior
>   to crashing NutHeapAvailable() reports 27KB of free memory.
>
>   I wonder if anyone else has attempted to use the IJG code or can
>   give me some pointers on what might be going wrong.  I'm new to
>   Ethernut and the Yagarto Tools and am inexperienced in C
>   programming so please be gentle.
>
>   Your help is much appreciated.
>
>Best Regards,
>Steve.
>
>
>
>------------------------------
>
>Message: 2
>Date: Thu, 12 Jun 2008 10:02:58 +1000
>From: Curtis Maloney <cmaloney at cardgate.net>
>Subject: Re: [En-Nut-Discussion] IJG jpeg decompression problem
>To: "Ethernut User Chat (English)" <en-nut-discussion at egnite.de>
>Message-ID: <485067B2.1060708 at cardgate.net>
>Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
>steve wrote:
> > Hi,
> >
> >   I'm trying to use Ethernut (on a SAM7X256-EK) with IJG's jpeg
> >   decompression code (ijg.org).  It kind of works but the process of
> >   decompressing a very small 16x16 pixel test image, which does generate
> >   the correct output, screws up NutNet in such a way that any subsequent
> >   call to NutUdpReceiveFrom or NutUdpSendTo immediately crashes
> >   the processor without an error message.  At the point just prior
> >   to crashing NutHeapAvailable() reports 27KB of free memory.
> >
> >   I wonder if anyone else has attempted to use the IJG code or can
> >   give me some pointers on what might be going wrong.  I'm new to
> >   Ethernut and the Yagarto Tools and am inexperienced in C
> >   programming so please be gentle.
>
>We used it for another project, on a different board, but what I can tell
>you is it's highly inefficient IFF you have the whole JPEG on hand to work
>from.  It's written to deal with slow incoming streams, being fed the data
>as they arrive.
>
>It would be much simpler, lighter code if it knew it had all the data on
>hand.  And, I dare say, would do a lot less messing about with de/allocating
>memory.
>
>--
>Curtis Maloney
>cmaloney at cardgate.net
>
>
>
>------------------------------
>
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>
>
>End of En-Nut-Discussion Digest, Vol 56, Issue 7
>************************************************