Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751313AbWAZDgK (ORCPT ); Wed, 25 Jan 2006 22:36:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751318AbWAZDgJ (ORCPT ); Wed, 25 Jan 2006 22:36:09 -0500 Received: from ns.miraclelinux.com ([219.118.163.66]:21221 "EHLO mail01.miraclelinux.com") by vger.kernel.org with ESMTP id S1751313AbWAZDgH (ORCPT ); Wed, 25 Jan 2006 22:36:07 -0500 Date: Thu, 26 Jan 2006 12:36:13 +0900 To: Grant Grundler Cc: Linux Kernel Development , linux-ia64@vger.kernel.org Subject: [PATCH 8/12] generic hweight{32,16,8}() Message-ID: <20060126033613.GG11138@miraclelinux.com> References: <20060125112625.GA18584@miraclelinux.com> <20060125113206.GD18584@miraclelinux.com> <20060125200250.GA26443@flint.arm.linux.org.uk> <20060125205907.GF9995@esmail.cup.hp.com> <20060126032713.GA9984@miraclelinux.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060126032713.GA9984@miraclelinux.com> User-Agent: Mutt/1.5.9i From: mita@miraclelinux.com (Akinobu Mita) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2160 Lines: 62 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); HAVE_ARCH_HWEIGHT_BITOPS is defined when the architecture has its own version of these functions. This code largely copied from: include/linux/bitops.h Index: 2.6-git/include/asm-generic/bitops.h =================================================================== --- 2.6-git.orig/include/asm-generic/bitops.h 2006-01-25 19:14:10.000000000 +0900 +++ 2.6-git/include/asm-generic/bitops.h 2006-01-25 19:14:11.000000000 +0900 @@ -458,14 +458,38 @@ #endif /* HAVE_ARCH_FFS_BITOPS */ +#ifndef HAVE_ARCH_HWEIGHT_BITOPS + /* * hweightN: returns the hamming weight (i.e. the number * of bits set) of a N-bit word */ -#define hweight32(x) generic_hweight32(x) -#define hweight16(x) generic_hweight16(x) -#define hweight8(x) generic_hweight8(x) +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); +} + +#endif /* HAVE_ARCH_HWEIGHT_BITOPS */ #endif /* __KERNEL__ */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/