From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 52E5A1F3FED for ; Wed, 26 Nov 2025 02:04:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764122643; cv=none; b=A9LavZH1qrWg+hJutwlLKS1bJ9NpK1QN26cV/9GGB3mXAPztqOsF+iMAR5UHYiLyced0U8YWs8c3wzogCGJ+uligMgneqg33i++9PwvNFjITXrBW/Z++955ds9XfNN9lS+V+saNbWYvdaG1Hij1MRPPLrtRykOljDz2xWM7TpyY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764122643; c=relaxed/simple; bh=V4ifOGvfV7xDEnB23nFtLinkTfX0hmKUFBLGoWfaWgA=; h=Date:From:To:CC:Subject:In-Reply-To:References:Message-ID: MIME-Version:Content-Type; b=bXYw7ndXL//uwMr3HILq2ogh616U2m0ZWsdqJovaGVwrlztQXQfGn0hYF+o5zi64xL7RboDE3V2+M9Z4SZAhVlVfTTlrx+DTljgPvboTgw03R7Tz/HPsL1Vs1M7BnnaglvZgLcA89l718JxtRNpofsN+38oadhxk43QxE9HYnOY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=G/j7q+Wz; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="G/j7q+Wz" Received: from ehlo.thunderbird.net (c-76-133-66-138.hsd1.ca.comcast.net [76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 5AQ23agp1688721 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Tue, 25 Nov 2025 18:03:37 -0800 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 5AQ23agp1688721 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2025112201; t=1764122618; bh=V4ifOGvfV7xDEnB23nFtLinkTfX0hmKUFBLGoWfaWgA=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=G/j7q+WzQOlDmIsL8w0Grrd0szBEPEFSc8myKhcSAXLhWkqzS0K2ohn56IjmunuvT AID3b5MQa2V0bcSzQNr0Qve0iHpf3iTHYYbxBMJufGcbeMTV5ymBZGoUsfSEf3x2tJ 029NfV/MwVNpKP6C4O2ws6Vqn2amJFvEL6hsUOYZGW2amsFIwbkGqh9vp0vdyAwUb5 JXO+tSavGSADILmJqrecWyhyi0KDcvRHXfvnjhWd6t38w/Nwki6oQP/oA6o/v8jE75 TFYXDy/D9RY0JzhrwAoFh1M+JLXDAd3jcA1w3bFM+5SvPYET9QwpPWiISYvJoDa2fs 8uLvlOC0/7rxA== Date: Tue, 25 Nov 2025 18:03:32 -0800 From: "H. Peter Anvin" To: Andrew Cooper , Linus Torvalds CC: LKML , the arch/x86 maintainers , Christian Ludloff Subject: Re: Code archaeology - 3DNow vs Pending Break Enable User-Agent: K-9 Mail for Android In-Reply-To: <800773c2-40c5-4c8b-87d5-e327db46985a@citrix.com> References: <2cd980dd-4342-4bc5-afe6-0548dedfaf24@citrix.com> <800773c2-40c5-4c8b-87d5-e327db46985a@citrix.com> Message-ID: <4D5BE8C1-04C9-470C-AB4D-F9DAEF5AD8E4@zytor.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable It was simply a matter of having two bits for the same thing, and the possi= bility (at the time) that Intel might allocate bit 31 for something=2E=20