On Fri, 23 November 2007 00:15:53 +0000, Daniel Drake wrote: > > What's the definition of an unaligned access? > ============================================= > > Unaligned memory accesses occur when you try to read N bytes of data starting > from an address that is not evenly divisible by N (i.e. addr % N != 0). > For example, reading 4 bytes of data from address 0x10000004 is fine, but > reading 4 bytes of data from address 0x10000005 would be an unaligned memory > access.
The wording could also apply to a DMA of 8k from a 4k-aligned address. But I don't have a good idea how to improve it. > It's safe to assume that memcpy will always copy bytewise and hence will > never cause an unaligned access. s/always copy/always behave as if copying/ memcpy usually copies at least wordwise, possibly even in bigger chunks. But that is just the inner loop. Unaligned bytes at the beginning/end receive special treatment. Jörn -- The rabbit runs faster than the fox, because the rabbit is rinning for his life while the fox is only running for his dinner. -- Aesop - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
