From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail01.miraclelinux.com (ns.miraclelinux.com [219.118.163.66]) by ozlabs.org (Postfix) with ESMTP id E13FB68A20 for ; Wed, 1 Feb 2006 20:03:28 +1100 (EST) Message-Id: <20060201090325.905071000@localhost.localdomain> References: <20060201090224.536581000@localhost.localdomain> Date: Wed, 01 Feb 2006 18:02:38 +0900 From: Akinobu Mita To: linux-kernel@vger.kernel.org Subject: [patch 14/44] generic hweight{64,32,16,8}() Cc: linux-mips@linux-mips.org, linux-ia64@vger.kernel.org, Ian Molton , David Howells , linuxppc-dev@ozlabs.org, Greg Ungerer , sparclinux@vger.kernel.org, Miles Bader , Linus Torvalds , Yoshinori Sato , Hirokazu Takata , linuxsh-shmedia-dev@lists.sourceforge.net, linux-m68k@lists.linux-m68k.org, Ivan Kokshaysky , Richard Henderson , Akinobu Mita , Chris Zankel , dev-etrax@axis.com, ultralinux@vger.kernel.org, Andi Kleen , linuxsh-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: , This patch introduces the C-language equivalents of the functions below: unsigned int hweight32(unsigned int w); unsigned int hweight16(unsigned int w); unsigned int hweight8(unsigned int w); unsigned long hweight64(__u64 w); In include/asm-generic/bitops/hweight.h This code largely copied from: include/linux/bitops.h Signed-off-by: Akinobu Mita include/asm-generic/bitops/hweight.h | 54 +++++++++++++++++++++++++++++++++++ 1 files changed, 54 insertions(+) Index: 2.6-git/include/asm-generic/bitops/hweight.h =================================================================== --- /dev/null +++ 2.6-git/include/asm-generic/bitops/hweight.h @@ -0,0 +1,54 @@ +#ifndef _ASM_GENERIC_BITOPS_HWEIGHT_H_ +#define _ASM_GENERIC_BITOPS_HWEIGHT_H_ + +#include + +/** + * hweightN - returns the hamming weight of a N-bit word + * @x: the word to weigh + * + * The Hamming Weight of a number is the total number of bits set in it. + */ + +static inline unsigned int hweight32(unsigned int w) +{ + unsigned int res = (w & 0x55555555) + ((w >> 1) & 0x55555555); + res = (res & 0x33333333) + ((res >> 2) & 0x33333333); + res = (res & 0x0F0F0F0F) + ((res >> 4) & 0x0F0F0F0F); + res = (res & 0x00FF00FF) + ((res >> 8) & 0x00FF00FF); + return (res & 0x0000FFFF) + ((res >> 16) & 0x0000FFFF); +} + +static inline unsigned int hweight16(unsigned int w) +{ + unsigned int res = (w & 0x5555) + ((w >> 1) & 0x5555); + res = (res & 0x3333) + ((res >> 2) & 0x3333); + res = (res & 0x0F0F) + ((res >> 4) & 0x0F0F); + return (res & 0x00FF) + ((res >> 8) & 0x00FF); +} + +static inline unsigned int hweight8(unsigned int w) +{ + unsigned int res = (w & 0x55) + ((w >> 1) & 0x55); + res = (res & 0x33) + ((res >> 2) & 0x33); + return (res & 0x0F) + ((res >> 4) & 0x0F); +} + +static inline unsigned long hweight64(__u64 w) +{ +#if BITS_PER_LONG == 32 + return hweight32((unsigned int)(w >> 32)) + hweight32((unsigned int)w); +#elif BITS_PER_LONG == 64 + u64 res; + res = (w & 0x5555555555555555ul) + ((w >> 1) & 0x5555555555555555ul); + res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul); + res = (res & 0x0F0F0F0F0F0F0F0Ful) + ((res >> 4) & 0x0F0F0F0F0F0F0F0Ful); + res = (res & 0x00FF00FF00FF00FFul) + ((res >> 8) & 0x00FF00FF00FF00FFul); + res = (res & 0x0000FFFF0000FFFFul) + ((res >> 16) & 0x0000FFFF0000FFFFul); + return (res & 0x00000000FFFFFFFFul) + ((res >> 32) & 0x00000000FFFFFFFFul); +#else +#error BITS_PER_LONG not defined +#endif +} + +#endif /* _ASM_GENERIC_BITOPS_HWEIGHT_H_ */ --