From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ulrich Eckhardt Date: Fri, 03 Feb 2006 08:31:42 +0000 Subject: Re: [patch 14/44] generic hweight{64,32,16,8}() Message-Id: <200602030931.43686.eckhardt@satorlaser.com> List-Id: References: <20060201090224.536581000@localhost.localdomain> <20060201090325.905071000@localhost.localdomain> In-Reply-To: <20060201090325.905071000@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Akinobu Mita Cc: linux-kernel@vger.kernel.org, Richard Henderson , Ivan Kokshaysky , Russell King , Ian Molton , dev-etrax@axis.com, David Howells , Yoshinori Sato , Linus Torvalds , linux-ia64@vger.kernel.org, Hirokazu Takata , linux-m68k@vger.kernel.org, Greg Ungerer , linux-mips@linux-mips.org, parisc-linux@parisc-linux.org, linuxppc-dev@ozlabs.org, linux390@de.ibm.com, linuxsh-dev@lists.sourceforge.net, linuxsh-shmedia-dev@lists.sourceforge.net, sparclinux@vger.kernel.org, ultralinux@vger.kernel.org, Miles Bader , Andi Kleen , Chris Zankel 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 03 Feb 2006 08:28:29 +0000 (GMT) Received: from mail.domino-uk.com ([193.131.116.193]:43535 "EHLO vMIMEsweeper.dps.local") by ftp.linux-mips.org with ESMTP id S8133350AbWBCI2K (ORCPT ); Fri, 3 Feb 2006 08:28:10 +0000 Received: from dps-exchange1.dps.local (dps-exchange1) by vMIMEsweeper.dps.local (Clearswift SMTPRS 5.0.4) with ESMTP id ; Fri, 3 Feb 2006 08:33:25 +0000 Received: from emea-exchange3.emea.dps.local ([192.168.50.10]) by dps-exchange1.dps.local with Microsoft SMTPSVC(5.0.2195.6713); Fri, 3 Feb 2006 08:33:25 +0000 Received: from tuxator2.emea.dps.local ([192.168.55.75]) by emea-exchange3.emea.dps.local with Microsoft SMTPSVC(6.0.3790.1830); Fri, 3 Feb 2006 09:26:27 +0100 From: Ulrich Eckhardt Organization: Sator Laser GmbH To: Akinobu Mita Subject: Re: [patch 14/44] generic hweight{64,32,16,8}() Date: Fri, 3 Feb 2006 09:31:42 +0100 User-Agent: KMail/1.8.3 Cc: linux-kernel@vger.kernel.org, Richard Henderson , Ivan Kokshaysky , Russell King , Ian Molton , dev-etrax@axis.com, David Howells , Yoshinori Sato , Linus Torvalds , linux-ia64@vger.kernel.org, Hirokazu Takata , linux-m68k@lists.linux-m68k.org, Greg Ungerer , linux-mips@linux-mips.org, parisc-linux@parisc-linux.org, linuxppc-dev@ozlabs.org, linux390@de.ibm.com, linuxsh-dev@lists.sourceforge.net, linuxsh-shmedia-dev@lists.sourceforge.net, sparclinux@vger.kernel.org, ultralinux@vger.kernel.org, Miles Bader , Andi Kleen , Chris Zankel References: <20060201090224.536581000@localhost.localdomain> <20060201090325.905071000@localhost.localdomain> In-Reply-To: <20060201090325.905071000@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200602030931.43686.eckhardt@satorlaser.com> X-OriginalArrivalTime: 03 Feb 2006 08:26:27.0578 (UTC) FILETIME=[86F36DA0:01C6289B] Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 10324 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: eckhardt@satorlaser.com Precedence: bulk X-list: linux-mips 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from vMIMEsweeper.dps.local (mail.domino-uk.com [193.131.116.193]) by ozlabs.org (Postfix) with ESMTP id 53715689F3 for ; Fri, 3 Feb 2006 19:43:35 +1100 (EST) From: Ulrich Eckhardt To: Akinobu Mita Subject: Re: [patch 14/44] generic hweight{64,32,16,8}() Date: Fri, 3 Feb 2006 09:31:42 +0100 References: <20060201090224.536581000@localhost.localdomain> <20060201090325.905071000@localhost.localdomain> In-Reply-To: <20060201090325.905071000@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Message-Id: <200602030931.43686.eckhardt@satorlaser.com> Cc: linux-mips@linux-mips.org, linux-ia64@vger.kernel.org, Ian Molton , Andi Kleen , David Howells , linuxppc-dev@ozlabs.org, Greg Ungerer , sparclinux@vger.kernel.org, Miles Bader , Yoshinori Sato , Hirokazu Takata , linuxsh-dev@lists.sourceforge.net, Linus Torvalds , Ivan Kokshaysky , Richard Henderson , Chris Zankel , 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 , parisc-linux@parisc-linux.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ulrich Eckhardt Date: Fri, 03 Feb 2006 08:31:42 +0000 Subject: Re: [patch 14/44] generic hweight{64,32,16,8}() Message-Id: <200602030931.43686.eckhardt@satorlaser.com> List-Id: References: <20060201090224.536581000@localhost.localdomain> <20060201090325.905071000@localhost.localdomain> In-Reply-To: <20060201090325.905071000@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Akinobu Mita Cc: linux-kernel@vger.kernel.org, Richard Henderson , Ivan Kokshaysky , Russell King , Ian Molton , dev-etrax@axis.com, David Howells , Yoshinori Sato , Linus Torvalds , linux-ia64@vger.kernel.org, Hirokazu Takata , linux-m68k@lists.linux-m68k.org, Greg Ungerer , linux-mips@linux-mips.org, parisc-linux@parisc-linux.org, linuxppc-dev@ozlabs.org, linux390@de.ibm.com, linuxsh-dev@lists.sourceforge.net, linuxsh-shmedia-dev@lists.sourceforge.net, sparclinux@vger.kernel.org, ultralinux@vger.kernel.org, Miles Bader , Andi Kleen , Chris Zankel 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751029AbWBCIdo (ORCPT ); Fri, 3 Feb 2006 03:33:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750952AbWBCIdo (ORCPT ); Fri, 3 Feb 2006 03:33:44 -0500 Received: from mail.domino-uk.com ([193.131.116.193]:38927 "EHLO vMIMEsweeper.dps.local") by vger.kernel.org with ESMTP id S1750836AbWBCIdm (ORCPT ); Fri, 3 Feb 2006 03:33:42 -0500 From: Ulrich Eckhardt Organization: Sator Laser GmbH To: Akinobu Mita Subject: Re: [patch 14/44] generic hweight{64,32,16,8}() Date: Fri, 3 Feb 2006 09:31:42 +0100 User-Agent: KMail/1.8.3 Cc: linux-kernel@vger.kernel.org, Richard Henderson , Ivan Kokshaysky , Russell King , Ian Molton , dev-etrax@axis.com, David Howells , Yoshinori Sato , Linus Torvalds , linux-ia64@vger.kernel.org, Hirokazu Takata , linux-m68k@vger.kernel.org, Greg Ungerer , linux-mips@linux-mips.org, parisc-linux@parisc-linux.org, linuxppc-dev@ozlabs.org, linux390@de.ibm.com, linuxsh-dev@lists.sourceforge.net, linuxsh-shmedia-dev@lists.sourceforge.net, sparclinux@vger.kernel.org, ultralinux@vger.kernel.org, Miles Bader , Andi Kleen , Chris Zankel References: <20060201090224.536581000@localhost.localdomain> <20060201090325.905071000@localhost.localdomain> In-Reply-To: <20060201090325.905071000@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200602030931.43686.eckhardt@satorlaser.com> X-OriginalArrivalTime: 03 Feb 2006 08:26:27.0578 (UTC) FILETIME=[86F36DA0:01C6289B] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 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