Quoting Ian McDonald: | On 6/29/07, Gerrit Renker <[EMAIL PROTECTED]> wrote: | > [DCCP]: Unaligned pointer access | > | > Signed-off-by: Gerrit Renker <[EMAIL PROTECTED]> | | Signed-off-by: Ian McDonald <[EMAIL PROTECTED]> | (I don't really understand the alignment stuff but trust you!) The described exceptions happened on a sparc64 machine (I don't have x86_64).
As far as I know on an i386 you can access unaligned data without performance penalty, on other machines (such as sparc64), unaligned access is handled by an exception handler - and this is very expensive. The get|put_unaligned in include/asm-xxx/unaligned.h avoid triggering the unaligned exception. It is not complicated, a nice summary is in Linux Device Drivers #3, Chapter 11 and examples are in include/asm-generic/unaligned.h - To unsubscribe from this list: send the line "unsubscribe dccp" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
