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=-3.8 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 A5CEEC433E3 for ; Thu, 16 Jul 2020 12:54:01 +0000 (UTC) Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6D86320739 for ; Thu, 16 Jul 2020 12:54:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="f1gEXFN0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6D86320739 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernelnewbies-bounces@kernelnewbies.org Received: from localhost ([::1] helo=shelob.surriel.com) by shelob.surriel.com with esmtp (Exim 4.94) (envelope-from ) id 1jw3O9-0000S5-V2; Thu, 16 Jul 2020 08:53:25 -0400 Received: from mail-il1-x12f.google.com ([2607:f8b0:4864:20::12f]) by shelob.surriel.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94) (envelope-from ) id 1jw3O7-0000Rw-RO for Kernelnewbies@kernelnewbies.org; Thu, 16 Jul 2020 08:53:23 -0400 Received: by mail-il1-x12f.google.com with SMTP id r12so4929259ilh.4 for ; Thu, 16 Jul 2020 05:53:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:reply-to:from:date:message-id :subject:to:cc:content-transfer-encoding; bh=yJIgJUH77nRGwlRpJ5OcGMH2MBDa33qmikVhDVWc4x8=; b=f1gEXFN0RUdy1wY3mxN8zZOaJ0hTPS39CRLNvTFpmbm88QLEjhYs5+k/OX65CPJo7b A//O2wJtKrgXNKvN0p6N3uujbJa9/vPxYdA8kg8zWNMzlKP7fIlO3Z7Z4YDxkQKhIT8H FoFv+gFnZ1VYTHCw5nuN7LCAWpAj1HeKTElk+KeIFSGTpo5VG91vlheG3JrFtfvQ7vHA KiDYin8g2aWR4Y8ehQZt3XzSnqSZf+ddIuZRLT7a9v6bKnXgqTbZ9Cvlpk/Z+Pi2usgB +XM/OVDJ8YreGAZ5wpWd6bsaZUUXTlRmH830CsI1n5vukUnyIWXd38LIO2/jSA2Kt5Jo AzRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:reply-to :from:date:message-id:subject:to:cc:content-transfer-encoding; bh=yJIgJUH77nRGwlRpJ5OcGMH2MBDa33qmikVhDVWc4x8=; b=i2rmo+NjjnNTTqhZZBbye9ZexemCruygF0JTDKl8jROnjl5Hm5hlkhp9a4DXTHerm7 fKkbwmPXIB081ej5uj7Mn2QA+aLgJQL8xR7m5yE65lSaWvGXwT9qago+PMk50uhxfcCR Owf7Z5ONikSWMIxAaoVCvFuOjd7aIW9iHwlzxNtoXBBSHZ3uk4FHf+sHrcb1aVxVCKWv CcT0WJLLW+ZdPRr77KtjPblG7bZOdilYhCcDBf5nMcC/g4tyIQIfDisB/XlPUBo4/Oc1 GaJE5EhzP4x3AFIIksxuFyFg8t5ZnX46lrX7CSww9kkJje2oULV23/KZESg27OPf1pOr em1w== X-Gm-Message-State: AOAM533XE27TL+QhsIgqX+CI6s7S8EWxJrIA7UYzd+SmoAfOa8RtJuCw bC/n3EA85Qbvo6wXBfeUFSGv2gMSgYU5ooyfI2Q= X-Google-Smtp-Source: ABdhPJxxV49SJ+2yPzyuXv8JQvJSOZqYZjPh5layi4wuzox5kMwMiZYfP1/x4pFwcgtbDjoC/Ln3bn9vudeNvINhnkg= X-Received: by 2002:a92:d181:: with SMTP id z1mr4475163ilz.41.1594903942283; Thu, 16 Jul 2020 05:52:22 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Jeffrey Walton Date: Thu, 16 Jul 2020 08:52:11 -0400 Message-ID: Subject: Re: How to comprehend this code snippet: __asm__ __volatile__("rdtsc" : "=A"(t))? To: =?UTF-8?B?5a2Z5LiW6b6ZIHN1bnNoaWxvbmc=?= Cc: kernelnewbies X-BeenThere: kernelnewbies@kernelnewbies.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Learn about the Linux kernel List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: noloader@gmail.com Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: kernelnewbies-bounces@kernelnewbies.org T24gVGh1LCBKdWwgMTYsIDIwMjAgYXQgODoyMiBBTSDlrZnkuJbpvpkgc3Vuc2hpbG9uZyA8c3Vu c2hpbG9uZzM2OUBnbWFpbC5jb20+IHdyb3RlOgo+Cj4gSGVyZSBpcyB0aGUgY29kZSBzbmlwcGV0 Ogo+ICNkZWZpbmUgaXBpcGVfcmVhZF90c2ModCkgICAgICAgICAgICAgIFwKPiBfX2FzbV9fIF9f dm9sYXRpbGVfXygicmR0c2MiIDogIj1BIih0KSkKCkkgaG9wZSB0aGF0IGlzIGkzODYgb25seSwg YW5kIG5vdCB4ODZfNjQuCgo+IEkgZm91bmQgdGhhdCB0aGUgcmR0c2MgKFJlYWQgVGltZS1TdGFt cCBDb3VudGVyKSBpbnN0cnVjdGlvbiBpcyB1c2VkCj4gdG8gZGV0ZXJtaW5lIGhvdyBtYW55IENQ VSB0aWNrcyB0b29rIHBsYWNlIHNpbmNlIHRoZSBwcm9jZXNzb3Igd2FzCj4gcmVzZXQuCj4KPiBC dXQgd2hhdCBkb2VzCj4gIj1BIih0KQo+IG1lYW4/CgpUaGUgJz1BJyBpcyBhIEdDQyBtYWNoaW5l IGNvbnN0cmFpbnQgZm9yIGkzODYgYW5kIGFuIG91dHB1dCBvcGVyYW5kLgpUaGUgJ0EnIGlzIHRo ZSBjb25zdHJhaW50IEVBWDpSRFggcmVnaXN0ZXIgcGFpci4gVGhlICc9JyBtZWFucyBpdCBpcwpi ZWluZyB3cml0dGVuIHRvLgoKQWxzbyBzZWUgaHR0cHM6Ly9nY2MuZ251Lm9yZy9vbmxpbmVkb2Nz L2djYy9NYWNoaW5lLUNvbnN0cmFpbnRzLmh0bWwKYW5kIGh0dHBzOi8vZ2NjLmdudS5vcmcvb25s aW5lZG9jcy9nY2MvRXh0ZW5kZWQtQXNtLmh0bWwuCgpBbHNvIHJlYWQgdGhlIG5vdGUgaW4gdGhl IE1hY2hpbmUgQ29uc3RyYWludHMgZm9yOgoKICAgIHVuc2lnbmVkIGxvbmcgbG9uZyByZHRzYyAo dm9pZCkKICAgIHsKICAgICAgdW5zaWduZWQgbG9uZyBsb25nIHRpY2s7CiAgICAgIF9fYXNtX18g X192b2xhdGlsZV9fKCJyZHRzYyI6Ij1BIih0aWNrKSk7CiAgICAgIHJldHVybiB0aWNrOwogICAg fQoKVGhlIG1hbnVhbCBzYXlzIHRoZSBwYXR0ZXJuIGlzIHdyb25nIGZvciB4ODZfNjQuCgpKZWZm CgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpLZXJuZWxu ZXdiaWVzIG1haWxpbmcgbGlzdApLZXJuZWxuZXdiaWVzQGtlcm5lbG5ld2JpZXMub3JnCmh0dHBz Oi8vbGlzdHMua2VybmVsbmV3Ymllcy5vcmcvbWFpbG1hbi9saXN0aW5mby9rZXJuZWxuZXdiaWVz Cg==