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 3CD18606A33A for ; Sat, 7 Nov 2026 14:06:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=EHt5UYJ7; dkim=fail reason="signature verification failed" (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=WOfL5CB5 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-Unsubscribe-Post:List-Owner; bh=ap1sReFvaf8bMvfxmiUSc7gSTQefuTUqP9V5UHntzuE=; b=EHt5UYJ73PTplq6ib+9cn8Hcct 8DVjhy6+8zqeRdKaAa1oKZdBt8XWsvZqK1JTIdM6qW8CxXDD3Zgzth4h8TLw035FObWCoUgrbMIvv JiVzey8gW9RtQNwEN/NuwKvBWbD5kWpCZtMc5uSrm46gaHOhm2wfQJdWbe3coMGVpdfrYAqRR1/qI W0XGl3toeWFCcFA30VJN9xoqeUyfjpOHX6Kql/a0PnviXYSUTau+aSq1JyUMj1q+Rn+3Dzpjb4CbR UGefdbxTYUb2kvYQfswrWNiDEDpAft/XOqm1w68kKiLkIo9sJEa/RLieF9+TYOnaJrc4Zy1HXpJB5 IgJDCg6w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xPh3v-0000000EmsT-07el; Sat, 07 Nov 2026 14:06:31 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xPh3t-0000000Ems5-3fNC for linux-riscv@lists.infradead.org; Sat, 07 Nov 2026 14:06:29 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 5913E41493; Sat, 7 Nov 2026 14:06:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 581C91F008A5; Sat, 7 Nov 2026 14:06:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794060389; bh=lN6MEVTLqxQZaRhIMVGcckvM4AhB2Yd9HdbNbDtVrlA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=WOfL5CB5L+dz7EAp/U9cZKaHOfkSdSte8r9Zl9PdDINIP8kqdNTpe9gExHHcQdRc+ pWa71RHtpZkQnijX8QDtR2sxvZOhw1XJkuunIrkapyy0Z8G5lX5rR+TBc8EeSF7Xy9 hjCn13ZaUNKh0ITroHRosAmPLqHjCFjMi5XJ+ObKs8ooJxToGY1umSXSxx8je0ZoAy IIVg1V9cmBbuPf2ZZfF2NJe0VTF88QYAXA/0mB5gY3NCSBa5YKjf/5bZhLIu5hwBYW em7cxjInqAzt3gc4VjceyoSAIgauthcJrM5S0I8SCsCkzdvi3NnGj/v89tvYNe0gS9 XyXH2FrSoeR8A== From: Jisheng Zhang To: Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Nam Cao Subject: [PATCH RESEND v5 2/3] riscv: word-at-a-time: improve find_zero() for RV32 Date: Sat, 7 Nov 2026 21:46:12 +0800 Message-ID: <20261107134613.17830-3-jszhang@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20261107134613.17830-1-jszhang@kernel.org> References: <20261107134613.17830-1-jszhang@kernel.org> X-Archived-By: MIME-Version: 1.0 X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" X-Spam-Status: No, score=-16.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT autolearn=ham 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 To remove non-necessary zero bits couting on RV32, replace the 'fls64(mask) >> 3' with '!mask ? 0 : ((__fls(mask) + 1) >> 3);' Signed-off-by: Jisheng Zhang Reviewed-by: Nam Cao --- arch/riscv/include/asm/word-at-a-time.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/include/asm/word-at-a-time.h b/arch/riscv/include/asm/word-at-a-time.h index ce04d6a088f6..f2d16c1eea8d 100644 --- a/arch/riscv/include/asm/word-at-a-time.h +++ b/arch/riscv/include/asm/word-at-a-time.h @@ -67,7 +67,7 @@ static inline unsigned long find_zero(unsigned long mask) { if (IS_ENABLED(CONFIG_RISCV_ISA_ZBB) && IS_ENABLED(CONFIG_TOOLCHAIN_HAS_ZBB) && riscv_has_extension_likely(RISCV_ISA_EXT_ZBB)) - return fls64(mask) >> 3; + return !mask ? 0 : ((__fls(mask) + 1) >> 3); return count_masked_bytes(mask); } -- 2.51.0 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv