From:
address@hidden
[mailto:address@hidden On Behalf
Of Muhamad Ikhwan Ismail
Sent: Friday, May 09, 2008 9:10 AM
To: address@hidden
Subject: [lwip-users] Misalignment problems on PowerPC (little endian
mode)
Hi,
I am interested in knowing if there is any other user of lwip who has managed
to implement lwip in PowerPC (little endian mode)
and got rid of the lil endian misalignment exceptions ? As lwip strips the
Ethernet header (14 bytes) the IP addr fields (4 bytes) in the IP header sits
on
a non-aligned address.My FEC is setup in a way that all received buffers are
stored directly into the pbufs instead of a temporary buffer to minimize
latency,
so the ethernet padding option does not really work for me. The FEC can only
save frames into addresses multiple of 16 only.
So for me (as far as my knowledge limits me :) ) there 2 other
possibilities left, one is packing the structure, or apply changes on the ip
address
functions and macros so that it works with the ip address as 2 16 bit fields
instead of 1 32 bits field. Unfortunately I couldnt make structure packing
work with my compiler (Wind River Compiler). I am interested in knowing if
anyone has done the same thing and mind sharing experience ? Any
thoughts,ideas and feedbacks would also be welcomed.
ps: I have an alignment fixing subroutine, but then again we want to minimize
the latency.
Greetings and thanks in advance
Ikhwan Ismail
ABB STOTZ-KONTAKT GmbH
Heidelberg
Germany
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