Messages in this thread | | | From | (Eric W. Biederman) | Subject | Re: [RFC] [PATCH 2/16] x86_64: Assembly safe page.h and pgtable.h | Date | Mon, 13 Nov 2006 19:41:17 -0700 |
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Andi Kleen <ak@suse.de> writes:
>> >> I think we need these UL suffixes. Otherwise in some cases overflow >> can take place and compiler emits warning. >> >> For ex. in following definition I got rid of UL. >> >> #define PGDIR_SIZE (1 << PGDIR_SHIFT) > > Yes for the shifts it is needed, but not for the unshifted constants. > I think. At least when they're hex the compiler should chose the right > type on its own.
Only if the high bit is set. But it should chose a big enough type. However there is no reason to play games and possibly out smart ourselves. That is the point of the _AC() macro. It adds the suffix only for C code, and drops it for assembly.
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