From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by oss.sgi.com id ; Mon, 13 Mar 2000 15:36:00 -0800 Received: from pneumatic-tube.sgi.com ([204.94.214.22]:49791 "EHLO pneumatic-tube.sgi.com") by oss.sgi.com with ESMTP id ; Mon, 13 Mar 2000 15:35:48 -0800 Received: from nodin.corp.sgi.com (nodin.corp.sgi.com [192.26.51.193]) by pneumatic-tube.sgi.com (980327.SGI.8.8.8-aspam/980310.SGI-aspam) via ESMTP id PAA09819; Mon, 13 Mar 2000 15:39:09 -0800 (PST) mail_from (owner-linux@cthulhu.engr.sgi.com) Received: from cthulhu.engr.sgi.com (cthulhu.engr.sgi.com [192.26.80.2]) by nodin.corp.sgi.com (980427.SGI.8.8.8/980728.SGI.AUTOCF) via ESMTP id PAA68297; Mon, 13 Mar 2000 15:35:47 -0800 (PST) Received: (from majordomo-owner@localhost) by cthulhu.engr.sgi.com (980427.SGI.8.8.8/970903.SGI.AUTOCF) id PAA36003 for linux-list; Mon, 13 Mar 2000 15:19:22 -0800 (PST) mail_from (owner-linux@relay.engr.sgi.com) Received: from sgi.com (sgi.engr.sgi.com [192.26.80.37]) by cthulhu.engr.sgi.com (980427.SGI.8.8.8/970903.SGI.AUTOCF) via ESMTP id PAA98779 for ; Mon, 13 Mar 2000 15:19:07 -0800 (PST) mail_from (kevink@mips.com) Received: from mx.mips.com (mx.mips.com [206.31.31.226]) by sgi.com (980327.SGI.8.8.8-aspam/980304.SGI-aspam: SGI does not authorize the use of its proprietary systems or networks for unsolicited or bulk email from the Internet.) via ESMTP id PAA09056 for ; Mon, 13 Mar 2000 15:19:07 -0800 (PST) mail_from (kevink@mips.com) Received: from newman.mips.com (newman [206.31.31.8]) by mx.mips.com (8.9.3/8.9.0) with ESMTP id PAA29449; Mon, 13 Mar 2000 15:18:59 -0800 (PST) Received: from Ulysses (par-c45-004-vty236.as.wcom.net [195.232.68.236]) by newman.mips.com (8.9.3/8.9.0) with SMTP id PAA24576; Mon, 13 Mar 2000 15:18:49 -0800 (PST) Message-ID: <005a01bf8d42$c656d2c0$ec44e8c3@Ulysses> From: "Kevin D. Kissell" To: "Harald Koerfgen" Cc: "Linux SGI" , "Linux/MIPS fnet" , Subject: Re: FP emulation patch available Date: Tue, 14 Mar 2000 00:20:36 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.1 X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 Sender: owner-linuxmips@oss.sgi.com Precedence: bulk Return-Path: X-Orcpt: rfc822;linuxmips-outgoing Herald Koerfgen writes: >Personally, I don't have any idea why the emulator works perfectly on an R3000 >but not on an R3912. Nor I, but in the absence of data, I'm happy to speculate. ;-) ... >Oh I see, I should have made myself more clear. I have a root filesystem on a >CF card based on declinuxroot (a cut down RedHat 5.1) and my Mobilon boots all >the way through to the login prompt if I delete the fsck from the initscripts. > >Booting into single user mode I can easily verify that tools like df or e2fsck >are bombing out with floating point exeptions. My "tests" with the emulator >have been so far: Does df survive? What does fsck do? and things like that. >Well, with the emulator all these tools make the Mobilon crash. Hard. So hard >that even the reset button doesn't work. There are two ways in which the FPU emulator is close enough to the hardware to be this sensitive to implementation. One is the way the emulator provokes an address error exception to execute a delay slot instruction following a simulated branch, but I don't think df or fsck do any branch-on-floating-conditions. The other is, of course, that it counts on getting sensible and recoverable coprocessor unusable exceptions. If the R3912 does something funky to the processor state on a CP1 unusable fault - an event that it doesn't have to deal with in its principal mission as a Windows CE platform - the results would be much what you are seeing. There are people at Toshiba who read this mailing list, so we can hope that they too are on the case and can maybe lend a clue... Regards, Kevin K. From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <005a01bf8d42$c656d2c0$ec44e8c3@Ulysses> From: "Kevin D. Kissell" Subject: Re: FP emulation patch available Date: Tue, 14 Mar 2000 00:20:36 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linuxmips@oss.sgi.com Return-Path: To: Harald Koerfgen Cc: Linux SGI , Linux/MIPS fnet , linux-mips@vger.rutgers.edu Message-ID: <20000313232036.ROw_AvC9RRvixujTkcOe89-m91dzFN8JNva4dsRCGvU@z> Herald Koerfgen writes: >Personally, I don't have any idea why the emulator works perfectly on an R3000 >but not on an R3912. Nor I, but in the absence of data, I'm happy to speculate. ;-) ... >Oh I see, I should have made myself more clear. I have a root filesystem on a >CF card based on declinuxroot (a cut down RedHat 5.1) and my Mobilon boots all >the way through to the login prompt if I delete the fsck from the initscripts. > >Booting into single user mode I can easily verify that tools like df or e2fsck >are bombing out with floating point exeptions. My "tests" with the emulator >have been so far: Does df survive? What does fsck do? and things like that. >Well, with the emulator all these tools make the Mobilon crash. Hard. So hard >that even the reset button doesn't work. There are two ways in which the FPU emulator is close enough to the hardware to be this sensitive to implementation. One is the way the emulator provokes an address error exception to execute a delay slot instruction following a simulated branch, but I don't think df or fsck do any branch-on-floating-conditions. The other is, of course, that it counts on getting sensible and recoverable coprocessor unusable exceptions. If the R3912 does something funky to the processor state on a CP1 unusable fault - an event that it doesn't have to deal with in its principal mission as a Windows CE platform - the results would be much what you are seeing. There are people at Toshiba who read this mailing list, so we can hope that they too are on the case and can maybe lend a clue... Regards, Kevin K.