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Re: Unaligned access to packed structs on ppc405




Matthew Jones wrote:

From: Yaro Pollak

Greetings,
I am cross-compiling on GCC 3.4.1 for the PowerPC 405,
which can handle unaligned accesses in hardware.
Whenever I am accessing members of a packed bit-struct by
pointer, the compiler produces byte accesses, instead of
4-byte acceses. I've tried to use |-mstrict-align but to
no avail. Am I doing something wrong?



Are you sure it is the compiler? Are you looking at the generated assembler, or inferring this from a logic analyser? If its the second case, it could be the uP rather than gcc.



I'm sorry I failed to mention that as well, but I am in fact looking at the generated assembler, vs. the assembler generated when I am accessing the members of the struct directly (not through a pointer).

Yaro


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