From: Rusty Russell <rusty@rustcorp.com.au>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Russell King <rmk+lkml@arm.linux.org.uk>,
Haavard Skinnemoen <hskinnemoen@atmel.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Linux Kernel Development <linux-kernel@vger.kernel.org>,
"Linux/m68k" <linux-m68k@vger.kernel.org>
Subject: Re: Yet more ARM breakage in linux-next
Date: Mon, 8 Dec 2008 16:50:34 +1030 [thread overview]
Message-ID: <200812081650.35014.rusty@rustcorp.com.au> (raw)
In-Reply-To: <Pine.LNX.4.64.0812072248430.14941@anakin>
On Monday 08 December 2008 08:20:59 Geert Uytterhoeven wrote:
> On Fri, 5 Dec 2008, Rusty Russell wrote:
> > +static inline int __fls(int x)
> ^^^ ^^^
> Other implementations take `unsigned long' and return `unsigned long'...
It's all over the place, actually. 32 bit archs are especially loose.
I've been toying with the idea of a boottime testsuite for all the
bitops to see who gets them wrong.
> > +static inline int __fls(unsigned long word)
> ^^^ ^^^^^^^^^^^^^
> > +{
> > + return fls(word) - 1;
> > +}
> > +
>
> ... but this one uses mixed types?
I cut and pasted. I thought you were 32 bit, so doesn't matter?
> What are the official semantics of __fls()?
Find last bit set in the word, undefined if word is 0. Returns 0
to BITS_PER_LONG-1.
Cheers,
Rusty.
prev parent reply other threads:[~2008-12-08 6:20 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-03 19:29 Yet more ARM breakage in linux-next Russell King
2008-12-03 20:41 ` Andrew Morton
2008-12-03 23:22 ` Rusty Russell
2008-12-03 23:37 ` Randy Dunlap
2008-12-03 23:46 ` Andrew Morton
2008-12-04 0:10 ` Alan Cox
2008-12-04 0:01 ` David Miller
2008-12-04 0:18 ` Randy Dunlap
2008-12-04 1:27 ` Rusty Russell
2008-12-04 2:56 ` Stephen Hemminger
2008-12-04 0:31 ` Russell King
2008-12-04 3:06 ` Nicolas Pitre
2008-12-04 1:33 ` Mike Frysinger
2008-12-04 2:15 ` Rusty Russell
2008-12-04 3:55 ` Mike Frysinger
2008-12-04 9:18 ` Geert Uytterhoeven
2008-12-04 14:12 ` Rusty Russell
2008-12-07 21:50 ` Geert Uytterhoeven
2008-12-08 6:20 ` Rusty Russell [this message]
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