From patchwork Tue Nov 9 05:51:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gibson X-Patchwork-Id: 1552662 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: bilbo.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; secure) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.a=rsa-sha256 header.s=201602 header.b=B0KQNn1b; dkim-atps=neutral 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-ppc-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 4HpHqt5r9Hz9sPf for ; Tue, 9 Nov 2021 17:19:06 +1100 (AEDT) Received: from localhost ([::1]:48630 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mkKTI-0005ec-Kd for incoming@patchwork.ozlabs.org; Tue, 09 Nov 2021 01:19:04 -0500 Received: from eggs.gnu.org ([209.51.188.92]:50090) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mkK3l-0004UH-FU; Tue, 09 Nov 2021 00:52:44 -0500 Received: from [2404:9400:2:0:216:3eff:fee2:21ea] (port=50211 helo=gandalf.ozlabs.org) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mkK3j-0006gz-16; Tue, 09 Nov 2021 00:52:40 -0500 Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4HpHDp1250z4xdq; Tue, 9 Nov 2021 16:52:10 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=201602; t=1636437130; bh=la4jD0mygrsjfKVP/LV8XfnLpo0mWqDcG5myMILlX44=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=B0KQNn1bGvj4N3uJjiwIwXmL78DwPQ6PKBv+DSVPWN74vlsoQZby6xMwA1Z4esyCI BmMJNVm65LuGDLep+nLRg7pJhRXmoG0j70hCVGYKcmA+XTBYocB/H2Tv5NnJhKic2W NvugKQXH9JffLBNIRFjCenofUD1/0ApeXX4XA4AI= From: David Gibson To: peter.maydell@linaro.org, clg@kaod.org, danielhb413@gmail.com, groug@kaod.org Subject: [PULL 15/54] host-utils: Introduce mulu128 Date: Tue, 9 Nov 2021 16:51:25 +1100 Message-Id: <20211109055204.230765-16-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211109055204.230765-1-david@gibson.dropbear.id.au> References: <20211109055204.230765-1-david@gibson.dropbear.id.au> MIME-Version: 1.0 X-Host-Lookup-Failed: Reverse DNS lookup failed for 2404:9400:2:0:216:3eff:fee2:21ea (failed) Received-SPF: pass client-ip=2404:9400:2:0:216:3eff:fee2:21ea; envelope-from=dgibson@gandalf.ozlabs.org; helo=gandalf.ozlabs.org X-Spam_score_int: -9 X-Spam_score: -1.0 X-Spam_bar: - X-Spam_report: (-1.0 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=0.25, RDNS_NONE=0.793, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-ppc@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Richard Henderson , Luis Pires , qemu-ppc@nongnu.org, qemu-devel@nongnu.org, David Gibson Errors-To: qemu-ppc-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-ppc" From: Luis Pires Signed-off-by: Luis Pires Reviewed-by: Richard Henderson Message-Id: <20211029192417.400707-6-luis.pires@eldorado.org.br> Signed-off-by: David Gibson --- 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