From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 15 Apr 2005 11:26:11 +0100 (BST) Received: from extgw-uk.mips.com ([IPv6:::ffff:62.254.210.129]:5143 "EHLO bacchus.net.dhis.org") by linux-mips.org with ESMTP id ; Fri, 15 Apr 2005 11:25:57 +0100 Received: from dea.linux-mips.net (localhost.localdomain [127.0.0.1]) by bacchus.net.dhis.org (8.13.1/8.13.1) with ESMTP id j3FAPnST007698; Fri, 15 Apr 2005 11:25:49 +0100 Received: (from ralf@localhost) by dea.linux-mips.net (8.13.1/8.13.1/Submit) id j3FAPmOX007697; Fri, 15 Apr 2005 11:25:48 +0100 Date: Fri, 15 Apr 2005 11:25:48 +0100 From: Ralf Baechle To: Dominic Sweetman Cc: Dominique Quatravaux , Peter Horton , linux-mips@linux-mips.org Subject: Re: [OFF-TOPIC] Cobalt 64-bit, what for? (was: 64-bit fix) Message-ID: <20050415102548.GD5414@linux-mips.org> References: <20050414185949.GA5578@skeleton-jack> <425F8776.6080703@kilimandjaro.dyndns.org> <20050415101422.GB5414@linux-mips.org> <16991.38112.114688.697412@arsenal.mips.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <16991.38112.114688.697412@arsenal.mips.com> User-Agent: Mutt/1.4.1i 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: 7736 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 Fri, Apr 15, 2005 at 11:18:08AM +0100, Dominic Sweetman wrote: > > > And doesn't 64 bit mode have costs of its own (doubled i-fetch bandwidth > > > for starters)? > > 64-bit MIPS CPUs still have 32-bit instructions... it's the registers > and addressing range which grow, not the instructions. True - but number of instructions will grow, thus the bandwidth needed to fetch them. > Program data segments tend to grow when you use 64-bit pointers (N64 > does, but N32 - paradoxically still a 64-bit ABI - doesn't) N32 is an ILP32 ABI so I'd count it as 32-bit. Ralf