Unaligned 64-bits access on FreeBSD/powerpc
Peter Grehan
grehan at freebsd.org
Thu Aug 3 18:52:06 UTC 2006
> Well, actually *nix has a long history of just killing the program with
> SIGBUS in such case.
>
> I am just wondering if it's really expected behavior on FreeBSD/powerpc
> or not.
No :(
What system are you running on ? I was pretty sure that G3/G4 CPUs
allowed unaligned accesses unless you explicitly disabled it (except for
cases such as vector ops). A 64 bit op on these CPUs should decompose
into separate 32-bit accesses ala i386 so the same case should occurr
for unaligned 32-bit ops.
In any event, the default should be that unaligned accesses are
handled, and then have switches to optionally uprintf the address, or
SIGBUS.
later,
Peter.
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