From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 91BD01993B1; Wed, 26 Feb 2025 07:14:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740554067; cv=none; b=O89MPQYKmIbU05RYMagaa9yF7rRBE2NK2giI4EXLOaIdfXfe2ahwJUm8mhfgqWA7o5XZnH5BEo4mOp61ES9bqhLFx8rtVx0BgP5S7GNdDfHqRnXjz6+L/Yq4d4ZccVtQiggglZ+Eh3Qfe+Pn5ryeukO9FQE/roNXKLV60WKEFBM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740554067; c=relaxed/simple; bh=lQkzvtRW6Jq4FuyRixXr8DUVI6AFJhoAhKyzE5400LQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Ftl+Sg/WlN61ekFMAgp0leX83VZZh3QC3ZXyFbYuxeI4ewWhPH+JzNiflef39mFFAy/DNpm1kS9EpRK/TnZsx47XEAmyBAWC/Ffp1EzymADbB6BTyInjkbYUP5mbkVMKyyEUw6KaavOtWf1ja9+6EsKBQrKn/aaynhF6jYrkE1E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=c9xkau5H; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="c9xkau5H" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 438FBC4CED6; Wed, 26 Feb 2025 07:14:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1740554067; bh=lQkzvtRW6Jq4FuyRixXr8DUVI6AFJhoAhKyzE5400LQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=c9xkau5HstyyjAg+iCdOXFOoMRN9gnbT8mNRacDl1qqOOEr2Pq8Bc3D7hnNRKDz/L Tu9ZvDrY/wElfwtV1neqWspf8wbf4oC2L/j+OEvpjw/goqGU26MmrFZ9Oc2pJ6Hs0B 72RYUhuo2JcIrJxETLtfaIqRY49WkLjZ1zEMNhnoqjDdkXTBqXJru/B9qDLncNi/Eb e2nVCZsoZ66fneV3XoE/ALeo1pAmgwoXp6eKOoa7e18dlurjsRFLv0hSmH7K3QK9sS SQbIpkVIf/syJfo7iHK93LiG8SEzI5DMNZfERkxh5iXkxNV5JkYSnyoqdg3SAM/shb 3hDZQq7nH9bkw== Message-ID: Date: Wed, 26 Feb 2025 08:14:14 +0100 Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 02/17] bitops: Add generic parity calculation for u64 To: Kuan-Wei Chiu , Yury Norov Cc: 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, akpm@linux-foundation.org, 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, Yu-Chun Lin References: <20250223164217.2139331-1-visitorckw@gmail.com> <20250223164217.2139331-3-visitorckw@gmail.com> Content-Language: en-US From: Jiri Slaby Autocrypt: addr=jirislaby@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 25. 02. 25, 14:29, Kuan-Wei Chiu wrote: >> +#define parity(val) \ >> +({ \ >> + u64 __v = (val); \ >> + int __ret; \ >> + switch (BITS_PER_TYPE(val)) { \ >> + case 64: \ >> + __v ^= __v >> 32; \ >> + fallthrough; \ >> + case 32: \ >> + __v ^= __v >> 16; \ >> + fallthrough; \ >> + case 16: \ >> + __v ^= __v >> 8; \ >> + fallthrough; \ >> + case 8: \ >> + __v ^= __v >> 4; \ >> + __ret = (0x6996 >> (__v & 0xf)) & 1; \ >> + break; \ >> + default: \ >> + BUILD_BUG(); \ >> + } \ >> + __ret; \ >> +}) >> + >> +#define parity8(val) parity((u8)(val)) >> +#define parity32(val) parity((u32)(val)) >> +#define parity64(val) parity((u64)(val)) >> > What do you think about using these inline functions instead of macros? > Except for parity8(), each function is a single line and follows the > same logic. I find inline functions more readable, and coding-style.rst > also recommends them over macros. Not in cases where macros are inevitable. I mean, do we need parityXX() for XX in (8, 16, 32, 64) at all? Isn't the parity() above enough for everybody? And if not, you can have all those parityXX() as inlines as you suggest, but also provide a macro such as the above to call (optimized) parityXX() as per datatype len. thanks, -- js suse labs