From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 14 Feb 2006 04:59:24 +0000 (GMT) Received: from ns.miraclelinux.com ([219.118.163.66]:42702 "EHLO mail01.miraclelinux.com") by ftp.linux-mips.org with ESMTP id S8133420AbWBNE6b (ORCPT ); Tue, 14 Feb 2006 04:58:31 +0000 Received: from mail01 (localhost.localdomain [127.0.0.1]) by mail01.miraclelinux.com (Postfix) with ESMTP id CBFAE31C325; Tue, 14 Feb 2006 14:04:45 +0900 (JST) Received: from localhost.localdomain (sshgate.miraclelinux.com []) by mail01.miraclelinux.com ([10.1.0.10]); Tue, 14 Feb 2006 05:04:45 +0000 Received: by localhost.localdomain (Postfix, from userid 1000) id 6B7EE420237; Tue, 14 Feb 2006 14:04:43 +0900 (JST) Message-Id: <20060214050443.261426000@localhost.localdomain> References: <20060214050351.252615000@localhost.localdomain> Date: Tue, 14 Feb 2006 14:03:59 +0900 From: Akinobu Mita To: linux-kernel@vger.kernel.org Cc: akpm@osdl.org, Russell King , Ian Molton , David Howells , Hirokazu Takata , Greg Ungerer , linux-mips@linux-mips.org, linuxsh-dev@lists.sourceforge.net, linuxsh-shmedia-dev@lists.sourceforge.net, sparclinux@vger.kernel.org, ultralinux@vger.kernel.org, Miles Bader , Akinobu Mita Subject: [patch 08/47] generic __ffs() Content-Disposition: inline; filename=__ffs-bitops.patch 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: 10434 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: mita@miraclelinux.com Precedence: bulk X-list: linux-mips This patch introduces the C-language equivalent of the function: unsigned long __ffs(unsigned long word); In include/asm-generic/bitops/__ffs.h This code largely copied from: include/asm-sparc/bitops.h Signed-off-by: Akinobu Mita include/asm-generic/bitops/__ffs.h | 43 +++++++++++++++++++++++++++++++++++++ 1 files changed, 43 insertions(+) Index: 2.6-rc/include/asm-generic/bitops/__ffs.h =================================================================== --- /dev/null +++ 2.6-rc/include/asm-generic/bitops/__ffs.h @@ -0,0 +1,43 @@ +#ifndef _ASM_GENERIC_BITOPS___FFS_H_ +#define _ASM_GENERIC_BITOPS___FFS_H_ + +#include + +/** + * __ffs - find first bit in word. + * @word: The word to search + * + * Undefined if no bit exists, so code should check against 0 first. + */ +static inline unsigned long __ffs(unsigned long word) +{ + int num = 0; + +#if BITS_PER_LONG == 64 + if ((word & 0xffffffff) == 0) { + num += 32; + word >>= 32; + } +#endif + if ((word & 0xffff) == 0) { + num += 16; + word >>= 16; + } + if ((word & 0xff) == 0) { + num += 8; + word >>= 8; + } + if ((word & 0xf) == 0) { + num += 4; + word >>= 4; + } + if ((word & 0x3) == 0) { + num += 2; + word >>= 2; + } + if ((word & 0x1) == 0) + num += 1; + return num; +} + +#endif /* _ASM_GENERIC_BITOPS___FFS_H_ */ --