Kelledin <[EMAIL PROTECTED]> writes: > Lately I've been looking closely at the compile logs on my EV56 > box, and I've noticed a particular gcc warning occurring > frequently: > > cast increases required alignment of target type. > > This worries me almost as much as casts between integers and > pointers of different size, but...even with all the warnings, I > don't get too many crashes.
Well, not surprising, since this will only lead to a problem if a) the pointer is actually dereferenced and b) the alignment is actually wrong. Often this cannot occur and the warning is bogus. > Still, I'm compelled to wonder about the effect of unaligned > accesses, i.e. how severe is an unaligned access in user-space? How > about in kernel-space? How does the system handle them? A trap to PALcode occurs and the firmware hands over to the operating system. The OS emulates the access and resumes the program. Takes probably about 100-200 cycles. > I have a pretty clear idea what it would take to fix that warning > condition, but it occurs so frequently that I'm not sure it would be > worth the time. :/ I don't think so, unless you actually see unaligned accesses in the syslog. -- Falk