>>>>> "Shaun" == Shaun Jackman <[EMAIL PROTECTED]> writes:
Shaun> On 8/2/05, Paul Koning <[EMAIL PROTECTED]> wrote:
>> It sounds like the workaround is to avoid memcpy, and just use
>> variable assignment. Alternatively, cast the pointers to char*,
>> which should force memcpy to do the right thing. Ugh.
Shaun> I swear originally, back in the gcc 2.95 days, I used memcpy
Shaun> because the memcpy function checked for unaligned pointers,
Shaun> whereas storing to and loading from unaligned variables
Shaun> generated a simple store/load instruction which wouldn't
Shaun> work. It seems the tables have turned and the exact opposite
Shaun> is true now with gcc 4, where memcpy doesn't work, but
Shaun> unaligned variables do. I believe gcc 3 behaved the same as
Shaun> gcc 2 -- memcpy worked, unaligned variables didn't work. Can
Shaun> someone confirm this summary is correct?
I'm pretty sure I have used unaligned load/store with gcc 2 as well as
3 and it works correctly. Certainly it should work correctly. If you
tell GCC to pack stuff, and it does (assigning odd offsets in the
process) then GCC is responsible for generating code to cope with
that. All this assuming you're not playing games with pointer
arithmetic to generate pointers that are less aligned than what GCC is
entitled to assume. If you saw something else, that would have been a
GCC bug.
paul
