From owner-freebsd-current Thu Apr 24 04:31:39 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id EAA01824 for current-outgoing; Thu, 24 Apr 1997 04:31:39 -0700 (PDT) Received: from gneiss.eps.nagoya-u.ac.jp (gneiss.eps.nagoya-u.ac.jp [133.6.57.99]) by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id EAA01817 for ; Thu, 24 Apr 1997 04:31:36 -0700 (PDT) Received: from marble.eps.nagoya-u.ac.jp (localhost [127.0.0.1]) by gneiss.eps.nagoya-u.ac.jp (8.8.5/3.4W4) with ESMTP id UAA03726; Thu, 24 Apr 1997 20:24:52 +0900 (JST) Message-Id: <199704241124.UAA03726@gneiss.eps.nagoya-u.ac.jp> To: rb@gid.co.uk Cc: kato@eclogite.eps.nagoya-u.ac.jp, freebsd-current@freebsd.org Subject: Re: Cyrix DX2/4 In-Reply-To: Your message of "Thu, 24 Apr 1997 11:06:33 +0100" References: X-Mailer: Mew version 1.70 on Emacs 19.28.1 / Mule 2.3 X-PGP-Fingerprint: 03 72 85 36 62 46 23 03 52 B1 10 22 44 10 0D 9E Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Thu, 24 Apr 1997 20:24:52 +0900 From: KATO Takenori Sender: owner-current@freebsd.org X-Loop: FreeBSD.org Precedence: bulk From: Bob Bishop Subject: Re: Cyrix DX2/4 Date: Thu, 24 Apr 1997 11:06:33 +0100 > I didn't have any problem until the new CPU flags were introduced. In old revision of initcpu.c, init_486() modified CR0 to disable CPU cache as: load_cr0(rcr0() | CR0_CD | CR0_NW); CD bit in CR0 becomes 1 after this line, and never become 0 when CYRIX_CACHE_WORKS is not set. This measn CPU cache is always disabled. This is the reason of performance loss you got. I changed init_486() and current init_486() doesn't diable CPU cache (I deleted above line). > (a) the BIOS is providing any necessary initialisation or (b) they don't > need any. If you doesn't set CYRIX_CACHE_WORKS, init_486() do nothing on DX2/DX4 box in initcpu.c revision >= 1.3. Does initcpu.c revision 1.3 still causes performance loss? If so, please let me know. ---- KATO Takenori Dept. Earth Planet. Sci., Nagoya Univ., Nagoya, 464-01, Japan PGP public key: finger kato@eclogite.eps.nagoya-u.ac.jp ------------------- Powered by FreeBSD(98) -------------------