Messages in this thread | | | Date | Tue, 20 Mar 2012 16:03:24 +0200 | Subject | Re: [RFC PATCH 1/6] kenrel.h: add ALIGN_OF_LAST_BIT() | From | Alexey Dobriyan <> |
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On Tue, Mar 20, 2012 at 2:32 PM, Michal Nazarewicz <mina86@mina86.com> wrote: > On Tue, 20 Mar 2012 11:21:19 +0100, Lai Jiangshan <laijs@cn.fujitsu.com> > wrote: > >> Get the biggest 2**y that x % (2**y) == 0 for the align value.
>> --- a/include/linux/kernel.h >> +++ b/include/linux/kernel.h >> @@ -44,6 +44,8 @@ >> #define PTR_ALIGN(p, a) ((typeof(p))ALIGN((unsigned >> long)(p), (a))) >> #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == >> 0) >> +#define ALIGN_OF_LAST_BIT(x) ((((x)^((x) - 1))>>1) + 1) > > > Wouldn't ALIGNMENT() be less confusing? After all, that's what this macro is > calculating, right? Alignment of given address.
Bits do not have alignment because they aren't directly addressable. Can you hardcode this sequence with comment, because it looks too special for macro. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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