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Date: Wed, 25 Jan 2006 16:06:18 -0800
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Subject: Re: [PATCH 3/6] C-language equivalents of include/asm-*/bitops.h
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References: <20060125112625.GA18584@miraclelinux.com> <20060125113206.GD18584@miraclelinux.com> <20060125200250.GA26443@flint.arm.linux.org.uk>
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On Wed, Jan 25, 2006 at 08:02:50PM +0000, Russell King wrote:
> > +	s = 16; if (word << 16 != 0) s = 0; b += s; word >>= s;
> > +	s =  8; if (word << 24 != 0) s = 0; b += s; word >>= s;
> > +	s =  4; if (word << 28 != 0) s = 0; b += s; word >>= s;
...
> Basically, shifts which depend on a variable are more expensive than
> constant-based shifts.

Actually, they're all constant shifts.  Just written stupidly.


r~