From patchwork Fri Jan 9 10:27:33 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frediano Ziglio X-Patchwork-Id: 427027 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 1958914012C for ; Fri, 9 Jan 2015 21:35:39 +1100 (AEDT) Received: from localhost ([::1]:49964 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y9Wun-0001ng-7k for incoming@patchwork.ozlabs.org; Fri, 09 Jan 2015 05:35:37 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56882) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y9WnH-0006EA-Lj for qemu-devel@nongnu.org; Fri, 09 Jan 2015 05:27:52 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Y9WnE-0006EP-CB for qemu-devel@nongnu.org; Fri, 09 Jan 2015 05:27:51 -0500 Received: from mail-we0-x236.google.com ([2a00:1450:400c:c03::236]:51904) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y9WnE-0006E7-1f for qemu-devel@nongnu.org; Fri, 09 Jan 2015 05:27:48 -0500 Received: by mail-we0-f182.google.com with SMTP id w62so7148779wes.13 for ; Fri, 09 Jan 2015 02:27:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id; bh=IHxs9Wv/QJPSBMdQUGCsLmEq3wMnVBfSOg7t5poPvJ4=; b=cfRUaqDFmuElAuhGbgy326MDKN7/s3jCxSKcXd1PD013K1xFXgyC6pLNP/BF/KkBG8 wg5DUl5kUDwjYTLQsQKrPwial6icWoEIO++zksUg8ScNIHLImPt6Ktny64M0Vat2KLMm l0Qw4b5VEyU8t/x9yBm+7Duxgxd7llAiLS/nsrg/l+ABuqtZFI+EjwfPWi2WddHXLIob 3+jvkDAYnsLtauIFjLLzIR5ZOVONBC9wdOJdnwO4GnYauamHoIuGvJu6N+rrVHxbtYqD gBMRY8dDWiM7Q1tOSQ4cP2uXVxP9PFQarGGQpHgdWxSS+yJ+wrJcdEAF1J9UawH5FEPg uA/g== X-Received: by 10.180.208.79 with SMTP id mc15mr3780676wic.34.1420799267086; Fri, 09 Jan 2015 02:27:47 -0800 (PST) Received: from localhost.localdomain ([90.152.119.35]) by mx.google.com with ESMTPSA id fp2sm25182429wib.8.2015.01.09.02.27.46 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 09 Jan 2015 02:27:46 -0800 (PST) From: Frediano Ziglio X-Google-Original-From: Frediano Ziglio To: Paolo Bonzini , Anthony Liguori , Stefan Hajnoczi Date: Fri, 9 Jan 2015 10:27:33 +0000 Message-Id: <1420799253-21911-1-git-send-email-frediano.ziglio@huawei.com> X-Mailer: git-send-email 1.9.1 X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2a00:1450:400c:c03::236 Cc: Frediano Ziglio , qemu-devel@nongnu.org Subject: [Qemu-devel] [PATCH] x86_64: optimise muldiv64 for x86_64 architecture X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org As this platform can do multiply/divide using 128 bit precision use these instruction to implement it. Signed-off-by: Frediano Ziglio --- include/qemu-common.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/include/qemu-common.h b/include/qemu-common.h index f862214..5366220 100644 --- a/include/qemu-common.h +++ b/include/qemu-common.h @@ -370,6 +370,7 @@ static inline uint8_t from_bcd(uint8_t val) } /* compute with 96 bit intermediate result: (a*b)/c */ +#ifndef __x86_64__ static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c) { union { @@ -392,6 +393,18 @@ static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c) res.l.low = (((rh % c) << 32) + (rl & 0xffffffff)) / c; return res.ll; } +#else +static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c) +{ + uint64_t res; + + asm ("mulq %2\n\tdivq %3" + : "=a"(res) + : "a"(a), "qm"((uint64_t) b), "qm"((uint64_t)c) + : "rdx", "cc"); + return res; +} +#endif /* Round number down to multiple */ #define QEMU_ALIGN_DOWN(n, m) ((n) / (m) * (m))