From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Ungerer Subject: Re: [uClinux-dev] [PATCH v2 1/6] m68k: merge mmu and non-mmu versions of muldi3 Date: Wed, 20 Apr 2011 19:08:28 +1000 Message-ID: <4DAEA28C.7020909@snapgear.com> References: <1303278880-16153-1-git-send-email-gerg@snapgear.com> <1303278880-16153-2-git-send-email-gerg@snapgear.com> <1303278880-16153-3-git-send-email-gerg@snapgear.com> <20110420080609.GA24244@merkur.ravnborg.org> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from sncsmrelay2.nai.com ([67.97.80.206]:13129 "EHLO sncsmrelay2.nai.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752257Ab1DTJJH (ORCPT ); Wed, 20 Apr 2011 05:09:07 -0400 In-Reply-To: <20110420080609.GA24244@merkur.ravnborg.org> Sender: linux-m68k-owner@vger.kernel.org List-Id: linux-m68k@vger.kernel.org To: Sam Ravnborg Cc: uClinux development list , linux-m68k@vger.kernel.org, Greg Ungerer Hi Sam, On 20/04/11 18:06, Sam Ravnborg wrote: > Hi Greg. > >> + >> +#if defined(__mc68020__) || defined(__mc68030__) || \ >> + defined(__mc68040__) || defined(__mc68060__) > > Why use these to decide if this is MMU or not? The asm code that is enclosed by this is not about having an MMU or not. It is about the processor supporting the 64bit mul instruction. > This code is not exposed to user-space so we can rely on CONFIG_* symbols. > IMO the CONIFG_* symbols is easier to read/maintain. In general yes I agree. But in this specific case it really is about a code generation option (what type of processor instructions we can emit). Regards Greg ------------------------------------------------------------------------ Greg Ungerer -- Principal Engineer EMAIL: gerg@snapgear.com SnapGear Group, McAfee PHONE: +61 7 3435 2888 8 Gardner Close FAX: +61 7 3217 5323 Milton, QLD, 4064, Australia WEB: http://www.SnapGear.com