From patchwork Tue Sep 6 12:55:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?V=C3=ADctor_Colombo?= X-Patchwork-Id: 12967605 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 A0C99ECAAD5 for ; Tue, 6 Sep 2022 14:24:40 +0000 (UTC) Received: from localhost ([::1]:54780 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oVZVH-0003hA-J0 for qemu-devel@archiver.kernel.org; Tue, 06 Sep 2022 10:24:39 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36388) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oVY8P-0001fx-8b; Tue, 06 Sep 2022 08:56:58 -0400 Received: from [200.168.210.66] (port=14617 helo=outlook.eldorado.org.br) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oVY8N-0002Pq-6s; Tue, 06 Sep 2022 08:56:56 -0400 Received: from p9ibm ([10.10.71.235]) by outlook.eldorado.org.br over TLS secured channel with Microsoft SMTPSVC(8.5.9600.16384); Tue, 6 Sep 2022 09:55:36 -0300 Received: from eldorado.org.br (unknown [10.10.70.45]) by p9ibm (Postfix) with ESMTP id 795C38002BE; Tue, 6 Sep 2022 09:55:36 -0300 (-03) From: =?utf-8?q?V=C3=ADctor_Colombo?= To: qemu-devel@nongnu.org, qemu-ppc@nongnu.org Cc: clg@kaod.org, danielhb413@gmail.com, david@gibson.dropbear.id.au, groug@kaod.org, richard.henderson@linaro.org, victor.colombo@eldorado.org.br, matheus.ferst@eldorado.org.br, lucas.araujo@eldorado.org.br, leandro.lupori@eldorado.org.br, lucas.coutinho@eldorado.org.br Subject: [PATCH v2 3/8] target/ppc: Zero second doubleword in DFP instructions Date: Tue, 6 Sep 2022 09:55:18 -0300 Message-Id: <20220906125523.38765-4-victor.colombo@eldorado.org.br> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220906125523.38765-1-victor.colombo@eldorado.org.br> References: <20220906125523.38765-1-victor.colombo@eldorado.org.br> MIME-Version: 1.0 X-OriginalArrivalTime: 06 Sep 2022 12:55:36.0976 (UTC) FILETIME=[F5A14100:01D8C1EF] X-Host-Lookup-Failed: Reverse DNS lookup failed for 200.168.210.66 (failed) Received-SPF: pass client-ip=200.168.210.66; envelope-from=victor.colombo@eldorado.org.br; helo=outlook.eldorado.org.br X-Spam_score_int: -10 X-Spam_score: -1.1 X-Spam_bar: - X-Spam_report: (-1.1 / 5.0 requ) BAYES_00=-1.9, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Starting at PowerISA v3.1, the second doubleword of the registers used to store results in DFP instructions are supposed to be zeroed. From the ISA, chapter 7.2.1.1 Floating-Point Registers: """ Chapter 4. Floating-Point Facility provides 32 64-bit FPRs. Chapter 5. Decimal Floating-Point also employs FPRs in decimal floating-point (DFP) operations. When VSX is implemented, the 32 FPRs are mapped to doubleword 0 of VSRs 0-31. (...) All instructions that operate on an FPR are redefined to operate on doubleword element 0 of the corresponding VSR. (...) and the contents of doubleword element 1 of the VSR corresponding to the target FPR or FPR pair for these instructions are set to 0. """ Before, the result stored at doubleword 1 was said to be undefined. With that, this patch changes the DFP facility to zero doubleword 1 when using set_dfp64 and set_dfp128. This fixes the behavior for ISA 3.1 while keeping the behavior correct for previous ones. Signed-off-by: Víctor Colombo Reviewed-by: Daniel Henrique Barboza --- target/ppc/dfp_helper.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/target/ppc/dfp_helper.c b/target/ppc/dfp_helper.c index 5ba74b2124..be7aa5357a 100644 --- a/target/ppc/dfp_helper.c +++ b/target/ppc/dfp_helper.c @@ -42,13 +42,16 @@ static void get_dfp128(ppc_vsr_t *dst, ppc_fprp_t *dfp) static void set_dfp64(ppc_fprp_t *dfp, ppc_vsr_t *src) { - dfp->VsrD(0) = src->VsrD(1); + dfp[0].VsrD(0) = src->VsrD(1); + dfp[0].VsrD(1) = 0ULL; } static void set_dfp128(ppc_fprp_t *dfp, ppc_vsr_t *src) { dfp[0].VsrD(0) = src->VsrD(0); dfp[1].VsrD(0) = src->VsrD(1); + dfp[0].VsrD(1) = 0ULL; + dfp[1].VsrD(1) = 0ULL; } static void set_dfp128_to_avr(ppc_avr_t *dst, ppc_vsr_t *src)