X-Authentication-Warning: delorie.com: mail set sender to djgpp-bounces using -f X-Received: by 10.224.163.14 with SMTP id y14mr2630172qax.3.1375847800639; Tue, 06 Aug 2013 20:56:40 -0700 (PDT) X-Received: by 10.50.3.70 with SMTP id a6mr336976iga.16.1375847800529; Tue, 06 Aug 2013 20:56:40 -0700 (PDT) Newsgroups: comp.os.msdos.djgpp Date: Tue, 6 Aug 2013 20:56:40 -0700 (PDT) In-Reply-To: <44qdnVq6LIkpiGrMnZ2dnUVZ_tidnZ2d@earthlink.com> Complaints-To: groups-abuse AT google DOT com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=113.196.180.138; posting-account=KYaziwoAAABDJCwXq2NZl-n94GouCm11 NNTP-Posting-Host: 113.196.180.138 References: <09068ed9-d989-4db5-bc71-2eabcbf1db53 AT googlegroups DOT com> <44qdnVq6LIkpiGrMnZ2dnUVZ_tidnZ2d AT earthlink DOT com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <3f7ac344-a8b1-4300-b7cd-5aacd97293f2@googlegroups.com> Subject: Re: Beta Test: CWSDPMI r7 - 4GB support From: jimmyliaoo AT gmail DOT com Injection-Date: Wed, 07 Aug 2013 03:56:40 +0000 Content-Type: text/plain; charset=ISO-8859-1 Bytes: 2530 Lines: 18 To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Reply-To: djgpp AT delorie DOT com Errors-To: nobody AT delorie DOT com X-Mailing-List: djgpp AT delorie DOT com X-Unsubscribes-To: listserv AT delorie DOT com Precedence: bulk > Let's suppose your computer has 4GB physical memory. Typically between > 2.5GB and 3.5GB of that memory is actually below the 4GB address point. The > remaining typically starts at the 4GB address point. On this computer you > could just sbrk() up to 4092K, > then touch the memory in order (first byte in each 4MB aligned page). I think what you want to express is: the remaining memory will be "re-mapped" to above 4GB address via sbrk(). Am I correct ? > If you then look at the physical map, you will very likely > have at least a 500MB buffer you can configure that actually is above the > 4GB address. Here "at least a 500MB buffer you can configure" means: application(or program) can access this buffer using "indirect" way, am I correct ? (where indirect way means you have to invoke api(or system call) to get pointer first, then access it...) If above is correct, then can I get the "physical memory address" of that buffer ? (the reason I ask is: H/W DMA transfer requires only the physical memory address !) * To sum up, s/w access that buffer(above 4GB physically) indirectly but h/w access it directly(no transform, no remap)