From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from penguin.netx4.com (embeddededge.com [209.113.146.155]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 9BDD767A33 for ; Fri, 1 Apr 2005 13:45:49 +1000 (EST) In-Reply-To: <1CFEB358338412458B21FAA0D78FE86D4F0D25@rennsmail02.eu.thmulti.com> References: <1CFEB358338412458B21FAA0D78FE86D4F0D25@rennsmail02.eu.thmulti.com> Mime-Version: 1.0 (Apple Message framework v619.2) Content-Type: text/plain; charset=US-ASCII; format=flowed Message-Id: <12cdcb5f3594a4e2b4869f3666079a8e@embeddededge.com> From: Dan Malek Date: Thu, 31 Mar 2005 22:45:39 -0500 To: "Fillod Stephane" Cc: linuxppc-dev@ozlabs.org Subject: Re: [PATCH] invalid instructions in kernel mode List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mar 31, 2005, at 2:17 PM, Fillod Stephane wrote: > What I don't understand, is how the FP load/store operations > in misc.S can "work" on a system with no FPU and *no* math-emu? What should happen is to follow the example used by 8xx for many years. As I said, when math emulation is disabled, there is still code that will emulate the load/store FP instructions. These instructions are used in may places even if user applications are compiled without any FP usage. > Many years? Allow me to doubt it's really used :). I wrote it in 1998 for the 8xx. I thought 4xx and e500 used the same model. If they don't, they should. > Though, it does work for 8xx thanks to Soft_emulate_8xx, but doesn't > for other FPU-less cores when CONFIG_MATH_EMULATION is disabled. Well, then that should get fixed. > So here is another patch, The only patch I'm interested in is making the 4xx and e500 follow the same path as 8xx. All of the non-FP cores should work the same way. The e500 is a special case because it doesn't have a classic FPU but rather can utilize the SPE for floating point. Put some thought into that. Thanks. -- Dan