From patchwork Wed May 25 13:49:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lucas Mateus Martins Araujo e Castro X-Patchwork-Id: 12861188 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 22299C433EF for ; Wed, 25 May 2022 13:57:01 +0000 (UTC) Received: from localhost ([::1]:33260 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ntrVU-0003kE-3j for qemu-devel@archiver.kernel.org; Wed, 25 May 2022 09:57:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58104) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ntrQ4-0005fD-ML; Wed, 25 May 2022 09:51:24 -0400 Received: from [187.72.171.209] (port=5282 helo=outlook.eldorado.org.br) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ntrQ3-0004iJ-44; Wed, 25 May 2022 09:51:24 -0400 Received: from p9ibm ([10.10.71.235]) by outlook.eldorado.org.br over TLS secured channel with Microsoft SMTPSVC(8.5.9600.16384); Wed, 25 May 2022 10:49:56 -0300 Received: from eldorado.org.br (unknown [10.10.70.45]) by p9ibm (Postfix) with ESMTP id F2418800761; Wed, 25 May 2022 10:49:55 -0300 (-03) From: "Lucas Mateus Castro(alqotel)" To: qemu-ppc@nongnu.org Cc: richard.henderson@linaro.org, clg@kaod.org, danielhb413@gmail.com, "Lucas Mateus Castro (alqotel)" , qemu-devel@nongnu.org (open list:All patches CC here) Subject: [PATCH RESEND v3 5/8] host-utils: Implemented signed 256-by-128 division Date: Wed, 25 May 2022 10:49:51 -0300 Message-Id: <20220525134954.85056-6-lucas.araujo@eldorado.org.br> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220525134954.85056-1-lucas.araujo@eldorado.org.br> References: <20220525134954.85056-1-lucas.araujo@eldorado.org.br> MIME-Version: 1.0 X-OriginalArrivalTime: 25 May 2022 13:49:56.0203 (UTC) FILETIME=[5151D3B0:01D8703E] X-Host-Lookup-Failed: Reverse DNS lookup failed for 187.72.171.209 (failed) Received-SPF: pass client-ip=187.72.171.209; envelope-from=lucas.araujo@eldorado.org.br; helo=outlook.eldorado.org.br X-Spam_score_int: -4 X-Spam_score: -0.5 X-Spam_bar: / X-Spam_report: (-0.5 / 5.0 requ) BAYES_00=-1.9, PDS_HP_HELO_NORDNS=0.659, 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" From: "Lucas Mateus Castro (alqotel)" Based on already existing QEMU implementation created a signed 256 bit by 128 bit division needed to implement the vector divide extended signed quadword instruction from PowerISA 3.1 Signed-off-by: Lucas Mateus Castro (alqotel) Reviewed-by: Richard Henderson --- include/qemu/host-utils.h | 1 + util/host-utils.c | 51 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 52 insertions(+) diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h index 9767af7573..bc743f5e32 100644 --- a/include/qemu/host-utils.h +++ b/include/qemu/host-utils.h @@ -851,4 +851,5 @@ static inline uint64_t udiv_qrnnd(uint64_t *r, uint64_t n1, } Int128 divu256(Int128 *plow, Int128 *phigh, Int128 divisor); +Int128 divs256(Int128 *plow, Int128 *phigh, Int128 divisor); #endif diff --git a/util/host-utils.c b/util/host-utils.c index 93dfb1b6ab..fb91bcba82 100644 --- a/util/host-utils.c +++ b/util/host-utils.c @@ -395,3 +395,54 @@ Int128 divu256(Int128 *plow, Int128 *phigh, Int128 divisor) return rem; } } + +/* + * Signed 256-by-128 division. + * Returns quotient via plow and phigh. + * Also returns the remainder via the function return value. + */ +Int128 divs256(Int128 *plow, Int128 *phigh, Int128 divisor) +{ + bool neg_quotient = false, neg_remainder = false; + Int128 unsig_hi = *phigh, unsig_lo = *plow; + Int128 rem; + + if (!int128_nonneg(*phigh)) { + neg_quotient = !neg_quotient; + neg_remainder = !neg_remainder; + + if (!int128_nz(unsig_lo)) { + unsig_hi = int128_neg(unsig_hi); + } else { + unsig_hi = int128_not(unsig_hi); + unsig_lo = int128_neg(unsig_lo); + } + } + + if (!int128_nonneg(divisor)) { + neg_quotient = !neg_quotient; + + divisor = int128_neg(divisor); + } + + rem = divu256(&unsig_lo, &unsig_hi, divisor); + + if (neg_quotient) { + if (!int128_nz(unsig_lo)) { + *phigh = int128_neg(unsig_hi); + *plow = int128_zero(); + } else { + *phigh = int128_not(unsig_hi); + *plow = int128_neg(unsig_lo); + } + } else { + *phigh = unsig_hi; + *plow = unsig_lo; + } + + if (neg_remainder) { + return int128_neg(rem); + } else { + return rem; + } +}