From patchwork Sun May 19 10:52:15 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aleksandar Markovic X-Patchwork-Id: 1101526 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=rt-rk.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 456Jrp23bYz9sCJ for ; Sun, 19 May 2019 20:57:30 +1000 (AEST) Received: from localhost ([127.0.0.1]:46895 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hSJVQ-0005ow-7V for incoming@patchwork.ozlabs.org; Sun, 19 May 2019 06:57:28 -0400 Received: from eggs.gnu.org ([209.51.188.92]:56581) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hSJRo-0003EQ-5i for qemu-devel@nongnu.org; Sun, 19 May 2019 06:53:45 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hSJRl-0001oD-Uk for qemu-devel@nongnu.org; Sun, 19 May 2019 06:53:44 -0400 Received: from mx2.rt-rk.com ([89.216.37.149]:42712 helo=mail.rt-rk.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hSJRl-00015m-N3 for qemu-devel@nongnu.org; Sun, 19 May 2019 06:53:41 -0400 Received: from localhost (localhost [127.0.0.1]) by mail.rt-rk.com (Postfix) with ESMTP id 813191A0F04; Sun, 19 May 2019 12:52:33 +0200 (CEST) X-Virus-Scanned: amavisd-new at rt-rk.com Received: from rtrkw774-lin.domain.local (rtrkw774-lin.domain.local [10.10.13.43]) by mail.rt-rk.com (Postfix) with ESMTPSA id 65A591A1FBA; Sun, 19 May 2019 12:52:33 +0200 (CEST) From: Aleksandar Markovic To: qemu-devel@nongnu.org Date: Sun, 19 May 2019 12:52:15 +0200 Message-Id: <1558263144-8776-2-git-send-email-aleksandar.markovic@rt-rk.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1558263144-8776-1-git-send-email-aleksandar.markovic@rt-rk.com> References: <1558263144-8776-1-git-send-email-aleksandar.markovic@rt-rk.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 89.216.37.149 Subject: [Qemu-devel] [PULL 01/10] target/mips: Make the results of DIV_. the same as on hardware X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, amarkovic@wavecomp.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Mateja Marjanovic MSA instructions DIV_. when dividing by zero, didn't return the same value when executed on a referent hardware (FPGA MIPS 64 r6, little endian) and when executed on QEMU, which is not a real bug, because the result when dividing by zero is UNPREDICTABLE [1] (page 141, 142). [1] MIPS Architecture for Programmers Volume IV-j: The MIPS64 SIMD Architecture Module, Revision 1.12 Signed-off-by: Mateja Marjanovic Signed-off-by: Aleksandar Markovic Reviewed-by: Aleksandar Markovic Message-Id: <1554207110-9113-2-git-send-email-mateja.marjanovic@rt-rk.com> --- target/mips/msa_helper.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/target/mips/msa_helper.c b/target/mips/msa_helper.c index c74e3cd..596190b 100644 --- a/target/mips/msa_helper.c +++ b/target/mips/msa_helper.c @@ -641,14 +641,15 @@ static inline int64_t msa_div_s_df(uint32_t df, int64_t arg1, int64_t arg2) if (arg1 == DF_MIN_INT(df) && arg2 == -1) { return DF_MIN_INT(df); } - return arg2 ? arg1 / arg2 : 0; + return arg2 ? arg1 / arg2 + : arg1 >= 0 ? -1 : 1; } static inline int64_t msa_div_u_df(uint32_t df, int64_t arg1, int64_t arg2) { uint64_t u_arg1 = UNSIGNED(arg1, df); uint64_t u_arg2 = UNSIGNED(arg2, df); - return u_arg2 ? u_arg1 / u_arg2 : 0; + return arg2 ? u_arg1 / u_arg2 : -1; } static inline int64_t msa_mod_s_df(uint32_t df, int64_t arg1, int64_t arg2)