From owner-freebsd-hackers@freebsd.org Wed Oct 14 18:51:37 2015 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 6AAA8A13D10 for ; Wed, 14 Oct 2015 18:51:37 +0000 (UTC) (envelope-from yaneurabeya@gmail.com) Received: from mail-qk0-x22d.google.com (mail-qk0-x22d.google.com [IPv6:2607:f8b0:400d:c09::22d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 26CFE10DF for ; Wed, 14 Oct 2015 18:51:37 +0000 (UTC) (envelope-from yaneurabeya@gmail.com) Received: by qkht68 with SMTP id t68so26774944qkh.3 for ; Wed, 14 Oct 2015 11:51:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=468P8C/ZPzqe4Z/hLz4UpsnHWT4NxquaY6yTIUv5Ctg=; b=Sm7lEKAD7AUqPR7ux8EaU6akomz3YOAeB1Ck/wpWf9nN47/tAHiljIcvjGaULusm0z M88fcwSyhQh33iRIS5Kbr0i/wgmlqBylfBXxq1vrjPbydrVtZ8uJJPPg3J45A3ylH1YX 4c21cB66XwQT8v7qZjf3yYouORfhKNYmjjlGB79T/5SWc4bOx8dlVXpiiju8jRAFbvjT Kg+/MhST2sz/Kqjmg3x6BKNHbQK0CWifJOfalO4vknf2qt6doAha0DMR2WNPIaqZ4dRT F0R8fXR2Lnt8hQs0spdb+wr6SsJXWsGgwEbRbuh5z4mMQqtfomn94XWKPmXvqNu4y5zw hUIQ== MIME-Version: 1.0 X-Received: by 10.55.22.162 with SMTP id 34mr6359210qkw.3.1444848696204; Wed, 14 Oct 2015 11:51:36 -0700 (PDT) Received: by 10.140.88.180 with HTTP; Wed, 14 Oct 2015 11:51:36 -0700 (PDT) In-Reply-To: <20151008093355.GS2257@kib.kiev.ua> References: <20151008072444.GO2257@kib.kiev.ua> <20151008080621.GP2257@kib.kiev.ua> <20151008093355.GS2257@kib.kiev.ua> Date: Wed, 14 Oct 2015 11:51:36 -0700 Message-ID: Subject: Re: Comparing behavior of test-fesetenv.c on AMD Opterons and Intel Xeons: running FNSTENV on Opteron -- should it zero out __x87.__other? From: NGie Cooper To: Konstantin Belousov Cc: "freebsd-hackers@freebsd.org" Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 Oct 2015 18:51:37 -0000 On Thu, Oct 8, 2015 at 2:33 AM, Konstantin Belousov wrote: > On Thu, Oct 08, 2015 at 02:14:12AM -0700, Garrett Cooper wrote: >> >> > On Oct 8, 2015, at 01:06, Konstantin Belousov wrote: >> > >> >> On Thu, Oct 08, 2015 at 12:38:15AM -0700, Garrett Cooper wrote: >> >> ... >> >> >> Hi kib! >> >> >> >> Ok -- that's what my gut was telling me when I was reading the spec, but I needed a second opinion. Interesting how Intel leaves the __other field alone and AMD [opterons] don't ;/.. >> > >> > Your statement does not make any sense. Re-read what I tell above. >> > The __other field is not written by code, the code does not change >> > by the matter of being run on Intel or AMD processors. It just happens >> > so that on one of your system the stack are seems to be zero, while on >> > another, it does not. >> >> I thought __other corresponded to C0-C3 based on my read of the spec -- is that incorrect? > > What are C0-C3 you reference ? I can only think about condition code > bits from the FPU status word which have that names, but the word is put > into the __status field of fenv_t. You're right. The __other field points to other registers in the FPU. __status covers what both the AMD64 and Intel x64 specs refer to as `C0-C3'. > And, what spec did you read ? I posted links to the specs in my original email. Unfortunately I didn't fully rewrite the bug report so where they factored into it in my original email was unfortunately lost: 1. http://support.amd.com/TechDocs/26569_APM_v5.pdf 2. http://www.intel.com/Assets/en_US/PDF/manual/253666.pdf Thanks! -NGie