From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16999 invoked by alias); 24 Feb 2005 22:30:18 -0000 Mailing-List: contact binutils-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: binutils-owner@sources.redhat.com Received: (qmail 16974 invoked from network); 24 Feb 2005 22:30:13 -0000 Received: from unknown (HELO MMS1.broadcom.com) (63.70.210.58) by sourceware.org with SMTP; 24 Feb 2005 22:30:13 -0000 Received: from 63.70.210.1 by MMS1.broadcom.com with SMTP (Broadcom SMTP Relay (Email Firewall v6.1.0)); Thu, 24 Feb 2005 14:30:35 -0800 X-Server-Uuid: 146C3151-C1DE-4F71-9D02-C3BE503878DD Received: from mail-irva-8.broadcom.com ([10.10.64.221]) by mail-irva-1.broadcom.com (Post.Office MTA v3.5.3 release 223 ID# 0-72233U7200L2200S0V35) with ESMTP id com; Thu, 24 Feb 2005 14:30:01 -0800 Received: from mon-irva-10.broadcom.com (mon-irva-10.broadcom.com [10.10.64.171]) by mail-irva-8.broadcom.com (MOS 3.5.6-GR) with ESMTP id AMJ26700; Thu, 24 Feb 2005 14:29:57 -0800 (PST) Received: from mail-sj1-5.sj.broadcom.com (mail-sj1-5.sj.broadcom.com [10.16.128.236]) by mon-irva-10.broadcom.com (8.9.1/8.9.1) with ESMTP id OAA06318; Thu, 24 Feb 2005 14:29:57 -0800 (PST) Received: from xl-sj1-01.sj.broadcom.com (xl-sj1-01 [10.16.129.245]) by mail-sj1-5.sj.broadcom.com (8.12.9/8.12.9/SSF) with ESMTP id j1OMTuov015748; Thu, 24 Feb 2005 14:29:56 -0800 (PST) Received: (from cgd@localhost) by xl-sj1-01.sj.broadcom.com ( 8.11.6/8.9.3) id j1OMTuE00694; Thu, 24 Feb 2005 14:29:56 -0800 X-Authentication-Warning: xl-sj1-01.sj.broadcom.com: cgd set sender to cgd@broadcom.com using -f To: "Richard Sandiford" cc: "Maciej W. Rozycki" , binutils@sources.redhat.com Subject: Re: [patch] MIPS: Fix synthesized doubleword transfers (ping) References: <87sm3lhdo1.fsf@firetop.home> <87oee9ha6p.fsf@firetop.home> From: cgd@broadcom.com Date: Fri, 25 Feb 2005 02:17:00 -0000 In-Reply-To: <87oee9ha6p.fsf@firetop.home> Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2 MIME-Version: 1.0 X-WSS-ID: 6E008A011JG6391122-01-01 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-SW-Source: 2005-02/txt/msg00626.txt.bz2 At Thu, 24 Feb 2005 22:20:30 +0000, Richard Sandiford wrote: > cgd@broadcom.com writes: > > At Thu, 24 Feb 2005 21:05:49 +0000 (UTC), "Richard Sandiford" wrote: > >> I suppose bad things could happen if you composed an aligned > >> address from an unaligned symbol and an unaligned offset, > >> but is that allowed? > > > > yes, at least as far as the ISA is concerned. > > I don't follow. The ISA has no concept of symbols vs. offsets. right, but to some degree symbol + offset -> base reg + offset, since the offsets in the base regs come directly from the relocs. the offsets in the instructions are 16-bit sign-extended values only -- no scale. some MIPS ISA levels, MIPS IV IIRC, had requirements that base reg must be properly aligned, and that offset must be properly aligned. (But IIRC those weren't present before MIPS IV, and aren't present in MIPS32/MIPS64.) chris