From mboxrd@z Thu Jan 1 00:00:00 1970 From: Finn Thain Subject: Re: FPU emulation incorrect for 68LC040? Date: Thu, 22 Jul 2010 11:05:42 +1000 (EST) Message-ID: References: <08EC3395-75C3-4E81-B468-C9978DDCF85D@bredband.net> <41EF646C-8866-4070-B772-94E39EF4620B@bredband.net> Mime-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="0-1601364300-1279760742=:354" Return-path: Received: from www.telegraphics.com.au ([204.15.192.19]:64825 "EHLO mail.telegraphics.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751575Ab0GVBOf (ORCPT ); Wed, 21 Jul 2010 21:14:35 -0400 In-Reply-To: <41EF646C-8866-4070-B772-94E39EF4620B@bredband.net> Sender: linux-m68k-owner@vger.kernel.org List-Id: linux-m68k@vger.kernel.org To: =?ISO-8859-15?Q?Mattias_Engdeg=E5rd?= Cc: Geert Uytterhoeven , linux-m68k@vger.kernel.org, zippel@linux-m68k.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --0-1601364300-1279760742=:354 Content-Type: TEXT/PLAIN; charset=ISO-8859-15 Content-Transfer-Encoding: QUOTED-PRINTABLE On Wed, 21 Jul 2010, Mattias Engdeg=E5rd wrote: > 21 jul 2010 kl. 22.32 skrev Geert Uytterhoeven: >=20 > > As the 'LC040 doesn't implement FPU instructions, I'd expect it to=20 > > just generate an exception when the "fadd.d (a0)+,fp0" is encountered.= =20 > > I.e. not do anything else, like postincrementing a0. >=20 > According to the manual, it generates a special 8-word exception frame=20 > that contains the decoded effective address, as a help to the emulator.= =20 > It only makes sense if the user can just use that EA right away (after=20 > having established that it is a memory operand). I suppose the only way= =20 > to find out is to find someone with a genuine 'LC040 (a non-buggy one). I have both kinds, buggy and non-buggy. Unfortunately, these machines=20 (PowerBooks) don't have working SCSI and the one with IDE has no Linux=20 filesystem. But if you send me some inline asm, I'll patch it into busybox and test a= =20 2.6.34 initramfs for you. Finn --0-1601364300-1279760742=:354--