Unaligned access to packed structs on ppc405

Matthew Jones matthewjones@vw1600e.org.uk
Mon Jan 30 16:18:00 GMT 2006

> 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.

Matthew JONES

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