From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Mon, 28 Jan 2008 21:18:08 +0000 (GMT) Received: from localhost.localdomain ([127.0.0.1]:206 "EHLO dl5rb.ham-radio-op.net") by ftp.linux-mips.org with ESMTP id S28584649AbYA1VSG (ORCPT ); Mon, 28 Jan 2008 21:18:06 +0000 Received: from denk.linux-mips.net (denk.linux-mips.net [127.0.0.1]) by dl5rb.ham-radio-op.net (8.14.1/8.13.8) with ESMTP id m0SLI44M020481; Mon, 28 Jan 2008 21:18:05 GMT Received: (from ralf@localhost) by denk.linux-mips.net (8.14.1/8.14.1/Submit) id m0SLI3h2020480; Mon, 28 Jan 2008 21:18:03 GMT Date: Mon, 28 Jan 2008 21:18:03 +0000 From: Ralf Baechle To: "M. Warner Losh" Cc: cfriesen@nortel.com, linux-mips@linux-mips.org Subject: Re: quick question on 64-bit values with 32-bit inline assembly Message-ID: <20080128211803.GA20434@linux-mips.org> References: <20080122175734.GA31013@linux-mips.org> <47963C31.2000403@nortel.com> <20080122200751.GA2672@linux-mips.org> <20080128.140245.-108809632.imp@bsdimp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080128.140245.-108809632.imp@bsdimp.com> User-Agent: Mutt/1.5.17 (2007-11-01) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 18156 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Mon, Jan 28, 2008 at 02:02:45PM -0700, M. Warner Losh wrote: > : this specific interaction of ABI and processor architecture then it was > : probably found not to implement such a special read because it is messy > : in more than one way. > > When 64-bit operations are enabled, you get all 64-bits. When they > aren't, only the lower 32-bits of the counter are provided (with sign > extension). So when operating in 32-bit mode, saving the upper 32 > bits are not necessary (or even possible). The architecture manual doesn't make a difference between 32-bit and 64-bit for rdhwr. My reading is the entire 64-bit would have to be transfered. Ralf