220 38127 <0e5ce74c-3e9e-4cf2-4afd-f7333ed82c5d@gmail.com> article Path: news.gmane.org!.POSTED!not-for-mail From: Andrey Semashev Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: memcpy/memset/etc overloads for volatile memory Date: Fri, 18 May 2018 23:46:33 +0300 Lines: 29 Approved: news@gmane.org Message-ID: <0e5ce74c-3e9e-4cf2-4afd-f7333ed82c5d@gmail.com> References: Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed X-Trace: blaine.gmane.org 1526676270 2275 195.159.176.226 (18 May 2018 20:44:30 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 18 May 2018 20:44:30 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCXY5TXHWYJRBLHX7TLQKGQEEMVC4IA@isocpp.org Fri May 18 22:44:26 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-lf0-f71.google.com ([209.85.215.71]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1fJmEj-0000Wf-E3 for gclcip-std-proposals@m.gmane.org; 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[109.173.28.102]) by smtp.googlemail.com with ESMTPSA id l124-v6sm2043522lfg.62.2018.05.18.13.46.33 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 18 May 2018 13:46:34 -0700 (PDT) In-Reply-To: Content-Language: en-US X-Original-Sender: andrey.semashev@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=KA8iVmVI; spf=pass (google.com: domain of andrey.semashev@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=andrey.semashev@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:38127 Archived-At: On 05/18/18 23:41, dgutson . wrote: > This might be interesting. > > In some systems, the implementation of memcpy() & friends cannot be used > for memory-mapped devices. > Usually, mapped memory is marked as volatile. > > I'm proposing to add volatile pointers overloads for the memcpy() > function and friends, without specifying exactly what should be > different at the standard-level, but allowing implementations to provide > a particular behavior. I'm just proposing to add the declaration to the > standard. > > Particularly, in some x86-based systems, reading things like the SPI > should be done on byte-per-byte basis (rather than streamed with any > SIMD instruction). > > I'm not sure what the wording should exactly say, but I'm just > initiating the discussion. If it's not specified then the exact behavior wrt. memory accesses is not going to be portable, which means it's not going to be useful. -- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/0e5ce74c-3e9e-4cf2-4afd-f7333ed82c5d%40gmail.com. .