From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D98CDC433ED for ; Wed, 12 May 2021 13:51:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 978BF611AC for ; Wed, 12 May 2021 13:51:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231224AbhELNw4 (ORCPT ); Wed, 12 May 2021 09:52:56 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:24561 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230347AbhELNwz (ORCPT ); Wed, 12 May 2021 09:52:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1620827506; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=hGtfPQ8bGGwrEI29kVoqsA6RSq1vPvN9kmTVPINf3V0=; b=AnGclM5wdHiemmW1vT2yWHUJ1LBtLzvY0zqu0GciKaRi2p/44yhgBgMtF5sCHDp5ES1CJa Qi7snz3GEQc3poE9/CNp1aoSDxzV5VfVqRgVJaYcWNKGx6XsXvfYbl/gJquneh8ADFrZTN PhXwGV+9MK6D0a1Marnqiue1NjkRDv8= Received: from mail-ej1-f70.google.com (mail-ej1-f70.google.com [209.85.218.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-394-dX24zYanNEqD0ALHfw_puw-1; Wed, 12 May 2021 09:51:45 -0400 X-MC-Unique: dX24zYanNEqD0ALHfw_puw-1 Received: by mail-ej1-f70.google.com with SMTP id z6-20020a17090665c6b02903700252d1ccso7169669ejn.10 for ; Wed, 12 May 2021 06:51:44 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=hGtfPQ8bGGwrEI29kVoqsA6RSq1vPvN9kmTVPINf3V0=; b=lsR3cR8DKM3mALTCehgZsIy9YhfF3B6zfeHBiUU1mbXC3e31A25DHG4P55wjSA5fyk j5Wlkn5WFR6DqHTfqaCYx52OnBQH2nfO5cERgR50aJnQDFgM/W9TsFqPxoT/LrX+Q8K+ gj0OPT1PQ3I6qRkNMyX+Uq2lrAV3EU8JDzlGbaTqh5oiK8+VmpeyzzAOKaKzJk8NlNcP OC11GofGVhoEaN5zljOFzvo2GWptiipsr49WbC7gBtWqLJZHOdRvYjMBJu7im3BWCaEG 0eLmhNxEGVwzgx4xe18vQdcanNT5Q6jqg+ye3D4+B5YcjzjIZ5sybScoIoMy0BHsvExA W2zg== X-Gm-Message-State: AOAM530nC5PH1KUamoTcRDMHOglkIszmIAG1O3XuoKhMPoDO7J7PupF1 h6SXJmdUG5w2iPXBJCZyYbKJNM5p0YxhDayrju9WfEpEUapRc+6mHGFXEcdZHhytYRbzgJ1oPDz O2lBwtUJ9TwLz8RopGz/zbqVplxCi2/MUdB0iYeteIZabqNFF1/uarWKgyRjYvOEl X-Received: by 2002:a50:fc99:: with SMTP id f25mr44216208edq.147.1620827502817; Wed, 12 May 2021 06:51:42 -0700 (PDT) X-Google-Smtp-Source: ABdhPJx3peCjOlPzPyprCGcFXw/UHqTB6I64tRVTgLMI91qT9rmIcIFkNiWrrS2Thp2wGE9qPtt/jg== X-Received: by 2002:a50:fc99:: with SMTP id f25mr44216180edq.147.1620827502552; Wed, 12 May 2021 06:51:42 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id bw26sm14278344ejb.119.2021.05.12.06.51.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 12 May 2021 06:51:42 -0700 (PDT) Subject: Re: [PATCH v2 kvm-unit-tests 2/2] arm: add eabi version of 64-bit division functions To: Alexandru Elisei , kvm@vger.kernel.org References: <20210512105440.748153-1-pbonzini@redhat.com> <20210512105440.748153-3-pbonzini@redhat.com> From: Paolo Bonzini Message-ID: <2d068920-26c2-610c-c27d-b693e406b180@redhat.com> Date: Wed, 12 May 2021 15:51:40 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 12/05/21 15:44, Alexandru Elisei wrote: >> + bl __udivmoddi4 >> + ldr r2, [sp, #8] // remainder returned in r2-r3 >> + ldr r3, [sp, #12] >> + add sp, sp, #16 >> + pop {r11, pc} > > I'm not sure what is going on here. Is the function returning 2 64bit arguments as > an 128bit vector? Or is the function being called from assembly and this is a > convention between it and the caller? It's an eABI convention that spans the runtime and the compiler. https://developer.arm.com/documentation/ihi0043/e/?lang=en#standardized-compiler-helper-functions says it returns a "pair of (unsigned) long longs is returned in {{r0, r1}, {r2, r3}}, the quotient in {r0, r1}, and the remainder in {r2, r3}." Paolo