From: Ulrich Eckhardt <eckhardt@satorlaser•com>
To: Akinobu Mita <mita@miraclelinux•com>
Cc: linux-mips@linux-mips•org, linux-ia64@vger•kernel.org,
Ian Molton <spyro@f2s•com>, Andi Kleen <ak@suse•de>,
David Howells <dhowells@redhat•com>,
linuxppc-dev@ozlabs•org, Greg Ungerer <gerg@uclinux•org>,
sparclinux@vger•kernel.org,
Miles Bader <uclinux-v850@lsi•nec.co.jp>,
Yoshinori Sato <ysato@users•sourceforge.jp>,
Hirokazu Takata <takata@linux-m32r•org>,
linuxsh-dev@lists•sourceforge.net,
Linus Torvalds <torvalds@osdl•org>,
Ivan Kokshaysky <ink@jurassic•park.msu.ru>,
Richard Henderson <rth@twiddle•net>,
Chris Zankel <chris@zankel•net>,
dev-etrax@axis•com, ultralinux@vger•kernel.org,
linux-m68k@lists•linux-m68k.org, linux-kernel@vger•kernel.org,
linuxsh-shmedia-dev@lists•sourceforge.net, linux390@de•ibm.com,
Russell King <rmk@arm•linux.org.uk>,
parisc-linux@parisc-linux•org
Subject: Re: [patch 14/44] generic hweight{64,32,16,8}()
Date: Fri, 3 Feb 2006 09:31:42 +0100 [thread overview]
Message-ID: <200602030931.43686.eckhardt@satorlaser.com> (raw)
In-Reply-To: <20060201090325.905071000@localhost.localdomain>
On Wednesday 01 February 2006 10:02, Akinobu Mita wrote:
> unsigned int hweight32(unsigned int w);
> unsigned int hweight16(unsigned int w);
> unsigned int hweight8(unsigned int w);
> unsigned long hweight64(__u64 w);
IMHO, this should use explicitly sized integers like __u8, __u16 etc, unless
there are stringent reasons like better register use - which is hard to tell
for generic C code. Also, why on earth is the returntype for hweight64 a
long?
> +static inline unsigned int hweight32(unsigned int w)
> +{
> + unsigned int res = (w & 0x55555555) + ((w >> 1) & 0x55555555);
> + res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
[...]
Why not use unsigned constants here?
> +static inline unsigned long hweight64(__u64 w)
> +{
[..]
> + u64 res;
> + res = (w & 0x5555555555555555ul) + ((w >> 1) & 0x5555555555555555ul);
Why not use initialisation here, too?
just my 2c
Uli
next prev parent reply other threads:[~2006-02-03 8:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20060201090224.536581000@localhost.localdomain>
2006-02-01 9:02 ` [patch 06/44] generic __{, test_and_}{set, clear, change}_bit() and test_bit() Akinobu Mita
2006-02-01 9:02 ` [patch 10/44] generic fls64() Akinobu Mita
2006-02-01 9:02 ` [patch 12/44] generic sched_find_first_bit() Akinobu Mita
2006-02-03 3:58 ` [parisc-linux] " Grant Grundler
2006-02-01 9:02 ` [patch 14/44] generic hweight{64,32,16,8}() Akinobu Mita
2006-02-01 9:06 ` Andi Kleen
2006-02-01 9:26 ` Michael Tokarev
2006-02-01 10:24 ` Andi Kleen
2006-02-02 12:50 ` Akinobu Mita
2006-02-02 1:26 ` Gabriel Paubert
2006-02-06 11:52 ` Akinobu Mita
2006-02-03 8:31 ` Ulrich Eckhardt [this message]
2006-02-01 9:02 ` [patch 31/44] powerpc: use generic bitops Akinobu Mita
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