Unaligned access to packed structs on ppc405

David Edelsohn dje@watson.ibm.com
Sun Jan 29 17:16:00 GMT 2006

>>>>> Yaro Pollak writes:

> 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.

	What does "|-mstrict-align" mean?  -mstrict-align means "do not
assume that unaligned accesses are handled by the system."  You are
requesting that the compiler assume the target requires strict alignment
and then questioning why it is accessing a packed bit-struct assuming the
least alignment.


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