From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=45.79.88.28 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792705482; b=3aF97JCalImYEX7fB4qEqK9AzBsOXKPqBVEr4JaSsgwF03zFGnUnLHFKK/qV04jwV1o/ 89/MGFKBtOqVnwXyCt5GI8Z3ruI5u+VQWxH0d8Ob8NNyi5mPg09qgLhr56nDGf/iRBjQK Augh/Ma5Ye7/vrtqGpc9ORJp+J2+b3GvoxKXnwvxtdt2zHlbaTQPdVrNHiWtInKdeWC2X CRG8gFtNvNLVWHyv3n/Wka6/Zo3pq3QyJ74Lt8kyCJ+pqo/Z8jIBUyUijF7Yean85faM1 x2N0+BW209Vt9DRngn5VF7GngGJ95gkhqg1KdqBYdTE0JPnUGxQYy8KyRZElVsHgS4Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792705482; h=DMARC-Filter:DKIM-Filter:DKIM-Signature:Received:From:To:Cc:Subject: In-Reply-To:References:Date:Message-ID:MIME-Version:Content-Type; bh=Woe6xHcsEP+dAFnzYb9P6peVQw4vpnrcC8v3BR/2jnE=; b=fhteExr8hcREUrCm8IGS20B3J9/NmOMDfeSTHRuKkyqVKFeL3thLx5DB9qfxeRgH5rFL znx8GFsENbFLUgoudxg2PE/CCaPgxkx4YuF+iKL+MR/u5RA5iVf2DJK/b2KReoTh2Stgo 8hM2XB2irZMIzSjDhAqrzFu/Hh4q+62tW0WrHxlxXQJvfMk9F0EUTaMTga/TQPhH48Aga gY4+Hk/F3Crdjcr4TWvBP/q3OddwrNt2mOr1B8dct5YDgB/xankCdaXS8YZGNwkD9SkM7 B9bcsZ+ffiD27R45KXizSRcj82NSYkfCpvsBIQ0OVjimCuLl6CNRE5TfMMktr5v2Iyw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=lwn.net; spf=pass smtp.mailfrom=lwn.net; dkim=pass header.d=lwn.net header.i=@lwn.net header.a=rsa-sha256 header.s=20201203 header.b=lhJJsOrJ; arc=none smtp.remote-ip=45.79.88.28 Received: from ms.lwn.net (ms.lwn.net [45.79.88.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DA8A9606A31A; Thu, 22 Oct 2026 21:44:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org DA8A9606A31A Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lwn.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lwn.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lwn.net header.i=@lwn.net header.a=rsa-sha256 header.s=20201203 header.b=lhJJsOrJ DKIM-Filter: OpenDKIM Filter v2.11.0 ms.lwn.net D63E8408F6 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lwn.net; s=20201203; t=1792705481; bh=Woe6xHcsEP+dAFnzYb9P6peVQw4vpnrcC8v3BR/2jnE=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=lhJJsOrJHzLb6hn6bv7VHV2+mYFyaQtqk92z4rf3sxZo/TyHcTlvOfRjkRsCZIrF0 Nip8jdgWVfzcS5qQI+OMAL+VtSulUBFCWcXY7gA8o/jOsJQsrstXMFjBdxeJfnxw9u 5wJdFCNdvqkzNXjHfSnYt93QL8pkpmOBk6cOJ0/N/5f3M6MHxTIjb7KxIyxwiL3gqZ eG8q9GbK58WGOoVPrjX3IaLo2gcnl9GFu9fn8NRI2Ejut7IYXkXkh45XCpYhNNTgiz h8WveE+lhUaTo/m2YMOszMhQ417gK5tNzbqnqVBrp7v1kgVKLoOtQV+68J6yOnW5dH /1Q9GqWTslmNg== Received: from localhost (unknown [IPv6:2601:280:4600:814::1fe]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by ms.lwn.net (Postfix) with ESMTPSA id D63E8408F6; Thu, 22 Oct 2026 21:44:40 +0000 (UTC) From: Jonathan Corbet To: Breno Rodrigues Alves , linux@armlinux.org.uk Cc: Bart Van Assche , James.Bottomley@HansenPartnership.com, mkp@kernel.org, linux-arm-kernel@lists.infradead.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Breno Rodrigues Alves Subject: Re: [PATCH v4] scsi: arm: Convert acornscsi-io.S to C In-Reply-To: <20261022210252.80844-1-breno3011alves@gmail.com> References: <20261022183658.58090-1-breno3011alves@gmail.com> <20261022210252.80844-1-breno3011alves@gmail.com> Date: Thu, 22 Oct 2026 15:44:40 -0600 Message-ID: <871p9h1kc7.fsf@trenco.lwn.net> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain Breno Rodrigues Alves writes: > The Acorn SCSI expansion card presents each 16-bit SCSI data halfword > on the low half of a 32-bit card access. The hand-written assembly > in acornscsi-io.S implements the two directions of the data path: > > - __acornscsi_in() : packs pairs of 16-bit card reads into 32-bit > memory words > - __acornscsi_out() : expands 16-bit memory halfwords into 32-bit > card writes (duplicating the halfword in both > halves for the bulk of the transfer) > > Both routines are simple pointer walks that a modern compiler handles > just as well as hand-written assembly, so replace the .S file with an > equivalent C implementation. How have you tested this change? jon