From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailer.gwdg.de (mailer.gwdg.de [134.76.10.26]) by sourceware.org (Postfix) with ESMTPS id 9293F3858408 for ; Wed, 5 Jul 2023 09:25:51 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 9293F3858408 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=gwdg.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gwdg.de Received: from excmbx-17.um.gwdg.de ([134.76.9.228] helo=email.gwdg.de) by mailer.gwdg.de with esmtp (GWDG Mailer) (envelope-from ) id 1qGylf-0005iF-S3; Wed, 05 Jul 2023 11:25:47 +0200 Received: from EXCMBX-29.um.gwdg.de (134.76.9.204) by excmbx-17.um.gwdg.de (134.76.9.228) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2507.27; Wed, 5 Jul 2023 11:25:47 +0200 Received: from fbmtpc21.tugraz.at (10.250.9.199) by EXCMBX-29.um.gwdg.de (134.76.9.204) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2507.27; Wed, 5 Jul 2023 11:25:47 +0200 Message-ID: <1be0adf325de7bf6cdb9c5caa7be2b41e5734786.camel@gwdg.de> Subject: Re: wishlist: support for shorter pointers From: Martin Uecker To: David Brown , =?UTF-8?Q?Rafa=C5=82?= Pietrak , Ian Lance Taylor CC: "Richard Earnshaw (lists)" , "gcc@gcc.gnu.org" Date: Wed, 5 Jul 2023 11:25:46 +0200 In-Reply-To: <8825a11f-e462-8d97-3cdf-a5015250f3c1@westcontrol.com> References: <439affd4-11fe-de80-94c8-6fc64cbf76ec@ztk-rp.eu> <112e711791835d56cca38654f83a009cb46707d4.camel@gwdg.de> <940e9ae5-8649-5a28-e29f-06f0b2982892@ztk-rp.eu> <6c881d3fc76d112d52ec668d05b68394ae792f30.camel@gwdg.de> <1eeef918-80d0-12a3-e7e9-5a75b25fb769@ztk-rp.eu> <8825a11f-e462-8d97-3cdf-a5015250f3c1@westcontrol.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.3-1+deb11u2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Originating-IP: [10.250.9.199] X-ClientProxiedBy: excmbx-24.um.gwdg.de (134.76.9.234) To EXCMBX-29.um.gwdg.de (134.76.9.204) X-Virus-Scanned: (clean) by clamav X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00,KAM_DMARC_STATUS,RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Am Mittwoch, dem 05.07.2023 um 11:11 +0200 schrieb David Brown: > On 05/07/2023 10:05, Rafał Pietrak via Gcc wrote: ... > > In my personal opinion (which you are all free to disregard), named > address spaces were an interesting idea that failed.  I was > enthusiastic > about a number of the extensions in TR 18307 "C Extensions to support > embedded processors" when the paper was first published.  As I > learned > more, however, I saw it was a dead-end.  The features are too > under-specified to be useful or portable, gave very little of use to > embedded programmers, and fit badly with C.  It was an attempt to > standardise and generalise some of the mess of different extensions > that > proprietary toolchain developers had for a variety of 8-bit CISC > microcontrollers that could not use standard C very effectively.  But > it > was all too little, too late - and AFAIK none of these proprietary > toolchains support it.  GCC supports some of the features to some > extent > - a few named address spaces on a few devices, for "gnuc" only (not > standard C, and not C++), and has some fixed point support for some > targets (with inefficient generated code - it appears to be little > more > than an initial "proof of concept" implementation). > > I do not think named address spaces have a future - in GCC or > anywhere > else.  The only real use of them at the moment is for the AVR for > accessing data in flash, and even then it is of limited success since > it > does not work in C++. Can you explain a little bit why you think it is a dead-end?  It seems an elegant solution to a range of problems to me. I have no idea how much the GCC features are actually used, but other compilers for  embedded systems such as SDCC also  support named address spaces.   Martin