Re: [RHEL5 PATCH 1/4] Provide fallback full 64-bit divide/modulus ops for gcc
From: Pavel Machek
Date: Fri Aug 18 2006 - 06:11:57 EST
On Tue 15-08-06 09:29:57, David Howells wrote:
> Andi Kleen <ak@xxxxxxx> wrote:
> > At least Linus' traditional argument against this is that it's better
> > to open code these (do_div) so that it's clear to the coder that they
> > are really costly.
> do_div() is not a full replacement for __udivdi3(), __umoddi3() or
> __udivmoddi4(), though I suspect we don't need divisor >= 2^32 anywhere atm.
> There are places where the compiler emits these that aren't entirely obvious,
> one of which IIRC is in ext2 inode allocation.
Well -- but that is good reason to keep that open-coded, right?
Thanks for all the (sleeping) penguins.
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