From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E3B67C021B3 for ; Sun, 23 Feb 2025 16:43:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=WBj30THC61+wMyF2Y0qHET5dj7Bybw0l50C4UvPEUDc=; b=VYbxxaz5Iu9VMF f+Kz0IXyVqyir/JhMTGLSmTvsP/V8KIWI9/npJGyrRX2WauOdaKr9wnj6Jyighq7Wp/8j7vyfuzAs U87k/m8hDHgNnEaV+5pQT9PLRN14kohuUQFL6JrUVf7fI3qA+zyyrcqPCVXIIiFcq0f/tvaYmrgbO fq2XHYYNI5Rjz0ZMSALrrf3juMWHpv4ra1RAeNMiJmg1R9XJdf9mjTC6C5cDlmhhNOYiDvCnz28cS 2H/bdK+2rqJOZXEJZL00JOd+cDe6VtunJQ7Nro30RMiBZ6PgIDcgbAjv0Z/+XLBnt1LCvoksDbmA+ BgWIjlWK6mnvsPrhVIlA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tmF4K-0000000BPZg-3PjS; Sun, 23 Feb 2025 16:43:04 +0000 Received: from mail-pj1-x1032.google.com ([2607:f8b0:4864:20::1032]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tmF4I-0000000BPYf-26gK for linux-mtd@lists.infradead.org; Sun, 23 Feb 2025 16:43:03 +0000 Received: by mail-pj1-x1032.google.com with SMTP id 98e67ed59e1d1-2fcc99efe9bso5600715a91.2 for ; Sun, 23 Feb 2025 08:43:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1740328982; x=1740933782; darn=lists.infradead.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=l8NvrVTMlDH5q7zXpF8J7bfqPimXPkp8jnsCRo60EBQ=; b=jbrZiFT/r9RiVIk1vAMgQM7Ty39mV4QAcBQ+iDmgZAwuVscASTF0wwncNrCMDAyqdL G85MmMH1n4esxjOjSieAvv8ZP8C99sTxRS04VhYATVTiexW+zS4Da9bnzFf0yzUudZJk QfRdu6WmMaq1xHTXc7GyJnrhtwE91Fx1BNUP1Ht7Rz4mgkl/umNVWyfhZaXoo40IaMoC sWL5zjNxYBGbXkDarixiLa6d6JNWJV6+p0MCvijhK75Wo4mNi5Wx56wO6yfdIudRtuSh vDuVMyPKhK77cjeQV9JlBl7NgJR4lK90crOS9ZMWZayylvGJaeRi5rcKZnEuTnWr3Lp6 m/pg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740328982; x=1740933782; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=l8NvrVTMlDH5q7zXpF8J7bfqPimXPkp8jnsCRo60EBQ=; b=Rd/hR+/mIVZMPLgGXb9OBcuqvIGCgZ/5jeKu3sJPpvKc6dqo+8dCNXxY4mOx+r12gX Ok+XAufzcjKnE5fy93kOqVgDSVB2amIZVgTHiJenCgmk7JVKkD1dpHblFaG/5VCDHmz7 mZz/KAMwYEXQE7SbO2PP4F4CbeFMJ17aaXsoEmGqGdvBLTtIZsSudwu3oGJC7xxKJEUa R8oFAwJRCFQkCUG6fLeN8m26OQIf4KKcql8zo0poDY9Z97spkhsGW6V/5kItJDML3aWH vJKnRqOzjijJTcaBjhw+rTtBE4mhsmBL7fcEt84KeY9AJ/t3AcYfiCbLGHQpW6w7slkJ dnHQ== X-Forwarded-Encrypted: i=1; AJvYcCWbSsWQyLIUB5jNWLnqMQogFcAEltC0OyqmIdxmJ1aZpfVPMYicZdoyj7P2sLc7Y1fcjLP0SClBTfo=@lists.infradead.org X-Gm-Message-State: AOJu0YwP76vj05kb5iGCxEG2RXisK+JmmSpIF8ITLogLeA0tAZ+XVHeT vbIgBl1I0fF62KZlLpO4H+huVygOETyIC04Z3ExfWgxKrevhQmqk X-Gm-Gg: ASbGncuYTvKIxz0LM2uZkuJQtHhzi1s7Ijefwli2s6j9ke45ZP9GW+j4usO6dUqYwmL R5uqWxfgzwq0pxV3LwkiHSqqz9kRZIytMrdX7wSaKwxIxM/eJcdDy/UicTCropsD5oh3xLvDcnV nkm0h3swi2ypKiDro+QXmjyFFrzlaZgm03vD9+ugGNPsJtuHWIzb/an4gAyjePlZHeb/mzo5hns MI9k6wTAp9iIa9er8vBm41zsJbYpBVENwxqBybunKlaJnJ/7y447kyYJulm0HKfwrlzUK92yRNB WSeVfp1I2OzpeRnarELR2OPtUspSybi+lxCaudJVpub+dgpW2Y8EBoCp X-Google-Smtp-Source: AGHT+IHY182dhZjo+LBq9qsTP5GtRPKleXwf977mCGplhz7BFQQV3AK7mJ142hsRvikrULeBFmErJw== X-Received: by 2002:a17:90b:4b90:b0:2ee:a6f0:f54 with SMTP id 98e67ed59e1d1-2fce86b31cdmr16578615a91.13.1740328981599; Sun, 23 Feb 2025 08:43:01 -0800 (PST) Received: from visitorckw-System-Product-Name.. ([140.113.216.168]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2fceb09f6e0sm4935080a91.44.2025.02.23.08.42.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 23 Feb 2025 08:43:01 -0800 (PST) From: Kuan-Wei Chiu To: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, jk@ozlabs.org, joel@jms.id.au, eajames@linux.ibm.com, andrzej.hajda@intel.com, neil.armstrong@linaro.org, rfoss@kernel.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, simona@ffwll.ch, dmitry.torokhov@gmail.com, mchehab@kernel.org, awalls@md.metrocast.net, hverkuil@xs4all.nl, miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com, louis.peens@corigine.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, parthiban.veerasooran@microchip.com, arend.vanspriel@broadcom.com, johannes@sipsolutions.net, gregkh@linuxfoundation.org, jirislaby@kernel.org, yury.norov@gmail.com, akpm@linux-foundation.org Cc: hpa@zytor.com, alistair@popple.id.au, linux@rasmusvillemoes.dk, Laurent.pinchart@ideasonboard.com, jonas@kwiboo.se, jernej.skrabec@gmail.com, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-fsi@lists.ozlabs.org, dri-devel@lists.freedesktop.org, linux-input@vger.kernel.org, linux-media@vger.kernel.org, linux-mtd@lists.infradead.org, oss-drivers@corigine.com, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, brcm80211@lists.linux.dev, brcm80211-dev-list.pdl@broadcom.com, linux-serial@vger.kernel.org, bpf@vger.kernel.org, jserv@ccns.ncku.edu.tw, Kuan-Wei Chiu , Yu-Chun Lin Subject: [PATCH 01/17] bitops: Add generic parity calculation for u32 Date: Mon, 24 Feb 2025 00:42:01 +0800 Message-Id: <20250223164217.2139331-2-visitorckw@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250223164217.2139331-1-visitorckw@gmail.com> References: <20250223164217.2139331-1-visitorckw@gmail.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250223_084302_539243_F1472C88 X-CRM114-Status: UNSURE ( 9.51 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org Several parts of the kernel open-code parity calculations using different methods. Add a generic parity32() helper implemented with the same efficient approach as parity8(). Co-developed-by: Yu-Chun Lin Signed-off-by: Yu-Chun Lin Signed-off-by: Kuan-Wei Chiu --- include/linux/bitops.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/include/linux/bitops.h b/include/linux/bitops.h index c1cb53cf2f0f..fb13dedad7aa 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -260,6 +260,27 @@ static inline int parity8(u8 val) return (0x6996 >> (val & 0xf)) & 1; } +/** + * parity32 - get the parity of an u32 value + * @value: the value to be examined + * + * Determine the parity of the u32 argument. + * + * Returns: + * 0 for even parity, 1 for odd parity + */ +static inline int parity32(u32 val) +{ + /* + * One explanation of this algorithm: + * https://funloop.org/codex/problem/parity/README.html + */ + val ^= val >> 16; + val ^= val >> 8; + val ^= val >> 4; + return (0x6996 >> (val & 0xf)) & 1; +} + /** * __ffs64 - find first set bit in a 64 bit word * @word: The 64 bit word -- 2.34.1 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/