From patchwork Fri Feb 12 15:02:21 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: LIU Zhiwei X-Patchwork-Id: 1439879 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) 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=) 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 ozlabs.org (Postfix) with ESMTPS id 4DccQh2QfWz9sCD for ; Sat, 13 Feb 2021 02:11:24 +1100 (AEDT) Received: from localhost ([::1]:39256 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lAa6M-0002hj-9J for incoming@patchwork.ozlabs.org; Fri, 12 Feb 2021 10:11:22 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:42990) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lAa5x-0002gz-3q; Fri, 12 Feb 2021 10:10:57 -0500 Received: from smtp2200-217.mail.aliyun.com ([121.197.200.217]:50699) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lAa5t-00078D-S9; Fri, 12 Feb 2021 10:10:56 -0500 X-Alimail-AntiSpam: AC=CONTINUE; BC=0.1636807|-1; CH=green; DM=|CONTINUE|false|; DS=CONTINUE|ham_system_inform|0.0202074-0.000563671-0.979229; FP=0|0|0|0|0|-1|-1|-1; HT=ay29a033018047207; MF=zhiwei_liu@c-sky.com; NM=1; PH=DS; RN=6; RT=6; SR=0; TI=SMTPD_---.JYH-.kU_1613142640; Received: from localhost.localdomain(mailfrom:zhiwei_liu@c-sky.com fp:SMTPD_---.JYH-.kU_1613142640) by smtp.aliyun-inc.com(10.147.40.2); Fri, 12 Feb 2021 23:10:41 +0800 From: LIU Zhiwei To: qemu-devel@nongnu.org Subject: [PATCH 03/38] target/riscv: Fixup saturate subtract function Date: Fri, 12 Feb 2021 23:02:21 +0800 Message-Id: <20210212150256.885-4-zhiwei_liu@c-sky.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210212150256.885-1-zhiwei_liu@c-sky.com> References: <20210212150256.885-1-zhiwei_liu@c-sky.com> Received-SPF: none client-ip=121.197.200.217; envelope-from=zhiwei_liu@c-sky.com; helo=smtp2200-217.mail.aliyun.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_NONE=0.001, UNPARSEABLE_RELAY=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: richard.henderson@linaro.org, LIU Zhiwei , qemu-riscv@nongnu.org, palmer@dabbelt.com, alistair23@gmail.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" The overflow predication ((a - b) ^ a) & (a ^ b) & INT64_MIN is right. However, when the predication is ture and a is 0, it should return maximum. Signed-off-by: LIU Zhiwei Reviewed-by: Richard Henderson Reviewed-by: Alistair Francis --- target/riscv/vector_helper.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c index 9371d70f6b..9786f630b4 100644 --- a/target/riscv/vector_helper.c +++ b/target/riscv/vector_helper.c @@ -2425,7 +2425,7 @@ int8_t ssub8(CPURISCVState *env, int vxrm, int8_t a, int8_t b) { int8_t res = a - b; if ((res ^ a) & (a ^ b) & INT8_MIN) { - res = a > 0 ? INT8_MAX : INT8_MIN; + res = a >= 0 ? INT8_MAX : INT8_MIN; env->vxsat = 0x1; } return res; @@ -2435,7 +2435,7 @@ int16_t ssub16(CPURISCVState *env, int vxrm, int16_t a, int16_t b) { int16_t res = a - b; if ((res ^ a) & (a ^ b) & INT16_MIN) { - res = a > 0 ? INT16_MAX : INT16_MIN; + res = a >= 0 ? INT16_MAX : INT16_MIN; env->vxsat = 0x1; } return res; @@ -2445,7 +2445,7 @@ int32_t ssub32(CPURISCVState *env, int vxrm, int32_t a, int32_t b) { int32_t res = a - b; if ((res ^ a) & (a ^ b) & INT32_MIN) { - res = a > 0 ? INT32_MAX : INT32_MIN; + res = a >= 0 ? INT32_MAX : INT32_MIN; env->vxsat = 0x1; } return res; @@ -2455,7 +2455,7 @@ int64_t ssub64(CPURISCVState *env, int vxrm, int64_t a, int64_t b) { int64_t res = a - b; if ((res ^ a) & (a ^ b) & INT64_MIN) { - res = a > 0 ? INT64_MAX : INT64_MIN; + res = a >= 0 ? INT64_MAX : INT64_MIN; env->vxsat = 0x1; } return res;