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Re: FW: eCos for MPC55xx
Gerster Jochen-B01096 wrote:
The problem is: The POWERPC gcc compiler (allocated from the ecos site)
optimize memcpy calls with small length, instead it uses its own inline
function without taking care of aligned access.
If it did not work for unaligned accesses on PowerPC in general, then this
would have been discovered years ago.
Perhaps have the semantics of an opcode in the MPC55xx changed so that
something that used to work for all PowerPC now only works on aligned
addresses? If so that wouldn't be good, but it's not beyond the realms of
possibility.
This is a very very big
problem using the TCP/IP stack because the IP-address is 4byte so the
gcc optimize and the offset of the IP-address in the different
protocol-headers varies. This ends in a exception :(
So I asking me now: I'm the only one with this problem? How do you solve
this problem, perhaps a compiler flag?
Theoretically -fno-builtin can be used to disable GCC's optimisations if
they are genuinely at fault. But I'm not sure. Have you tried a small
testcase? And if so have you looked at the assembler GCC is producing?
Jifl
--
--["No sense being pessimistic, it wouldn't work anyway"]-- Opinions==mine