From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 67B3B606A31B for ; Thu, 22 Oct 2026 21:44:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=F1CbMERJ; 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-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: Message-ID:Date:References:In-Reply-To:Subject:Cc:To:From:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; bh=Woe6xHcsEP+dAFnzYb9P6peVQw4vpnrcC8v3BR/2jnE=; b=F1CbMERJehJDU4sEXZpcHJpRi1 0cfM5bC0JFRL9BfDnpMSgbF7fMJnX2wBBfONKtVXMEaMDZ93fSnIrtu7LTDKOJfBT5F3d77OWimpu rfvjITAOzdZBeaVcDlutSaAEG24x5lj++gv0v3L5dpGFqZl+0wpdJtmdmTNvwOllq7KhhaqGLvP7b nVKVAfuNjEAt5dp37K0bNVIHil1HR+IbaEcFK0mQk4krAu4T5pS4MKr8+HKCiX4bNmLXQ7/6tIIpz 5aOl5t2mybIwHnqSRT0l1KUCPWARY+RyPsiCN72wojqnvi/c3Ov/9jT/BslBLejOXQlCIbxx1JRYE DcCe+NTA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xK0ac-0000000F1DD-2Qz0; Thu, 22 Oct 2026 21:44:46 +0000 Received: from ms.lwn.net ([45.79.88.28]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xK0aZ-0000000F1Cm-3DMY for linux-arm-kernel@lists.infradead.org; Thu, 22 Oct 2026 21:44:45 +0000 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-Archived-By: MIME-Version: 1.0 Content-Type: text/plain X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261022_144443_852371_BC84F575 X-CRM114-Status: UNSURE ( 8.39 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -2.1 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-5.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 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