From patchwork Mon Oct 25 19:11:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Fernando Fujita Pires X-Patchwork-Id: 1545947 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 bilbo.ozlabs.org (Postfix) with ESMTPS id 4HdQNR4Hf9z9shn for ; Tue, 26 Oct 2021 06:43:03 +1100 (AEDT) Received: from localhost ([::1]:33294 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mf5s5-0001jq-Bw for incoming@patchwork.ozlabs.org; Mon, 25 Oct 2021 15:43:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42088) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mf5Q0-0000yP-0X; Mon, 25 Oct 2021 15:14:00 -0400 Received: from [201.28.113.2] (port=13660 helo=outlook.eldorado.org.br) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mf5Py-0000Ju-5f; Mon, 25 Oct 2021 15:13:59 -0400 Received: from power9a ([10.10.71.235]) by outlook.eldorado.org.br with Microsoft SMTPSVC(8.5.9600.16384); Mon, 25 Oct 2021 16:12:27 -0300 Received: from eldorado.org.br (unknown [10.10.70.45]) by power9a (Postfix) with ESMTP id 4FDB7800BA7; Mon, 25 Oct 2021 16:12:27 -0300 (-03) From: Luis Pires To: qemu-devel@nongnu.org, qemu-ppc@nongnu.org Subject: [PATCH v4 09/19] host-utils: Introduce mulu128 Date: Mon, 25 Oct 2021 16:11:44 -0300 Message-Id: <20211025191154.350831-10-luis.pires@eldorado.org.br> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211025191154.350831-1-luis.pires@eldorado.org.br> References: <20211025191154.350831-1-luis.pires@eldorado.org.br> MIME-Version: 1.0 X-OriginalArrivalTime: 25 Oct 2021 19:12:27.0579 (UTC) FILETIME=[401078B0:01D7C9D4] X-Host-Lookup-Failed: Reverse DNS lookup failed for 201.28.113.2 (failed) Received-SPF: pass client-ip=201.28.113.2; envelope-from=luis.pires@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, PDS_HP_HELO_NORDNS=0.001, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no 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: Luis Pires , richard.henderson@linaro.org, groug@kaod.org, david@gibson.dropbear.id.au Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Signed-off-by: Luis Pires Reviewed-by: Richard Henderson --- include/qemu/host-utils.h | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h index a3a7ced78d..ca979dc6cc 100644 --- a/include/qemu/host-utils.h +++ b/include/qemu/host-utils.h @@ -590,6 +590,42 @@ static inline bool umul64_overflow(uint64_t x, uint64_t y, uint64_t *ret) #endif } +/* + * Unsigned 128x64 multiplication. + * Returns true if the result got truncated to 128 bits. + * Otherwise, returns false and the multiplication result via plow and phigh. + */ +static inline bool mulu128(uint64_t *plow, uint64_t *phigh, uint64_t factor) +{ +#if defined(CONFIG_INT128) && \ + (__has_builtin(__builtin_mul_overflow) || __GNUC__ >= 5) + bool res; + __uint128_t r; + __uint128_t f = ((__uint128_t)*phigh << 64) | *plow; + res = __builtin_mul_overflow(f, factor, &r); + + *plow = r; + *phigh = r >> 64; + + return res; +#else + uint64_t dhi = *phigh; + uint64_t dlo = *plow; + uint64_t ahi; + uint64_t blo, bhi; + + if (dhi == 0) { + mulu64(plow, phigh, dlo, factor); + return false; + } + + mulu64(plow, &ahi, dlo, factor); + mulu64(&blo, &bhi, dhi, factor); + + return uadd64_overflow(ahi, blo, phigh) || bhi != 0; +#endif +} + /** * uadd64_carry - addition with carry-in and carry-out * @x, @y: addends