Message-ID: <362A2D79.FC9223A8@mcis.de> Date: Sun, 18 Oct 1998 19:03:37 +0100 From: Gero Timann Organization: MediaCompany Goe X-Mailer: Mozilla 4.05 [de]C-NECCK (Win95; I) MIME-Version: 1.0 Newsgroups: comp.os.msdos.djgpp To: djgpp AT delorie DOT com Subject: Re: UDMA <-> getting physical address of an array ? References: Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Reply-To: djgpp AT delorie DOT com Hi,Hi ! I only read FAQ201 at this time, no such point found ... Oh, its in the new FAQ211. Ok, i promise to read your newest FAQ (is 211 your newest ?) before asking such silly questions above. Nevertheless, many thanks for your hints. Now i have to proof, whether i should reprogram my project in BC5 using WDOSX or not...arghh, the windows-development-enviroment is horrible.. Regards, Gero Eli Zaretskii schrieb: > On Sat, 17 Oct 1998, Gero Timann wrote: > > > Another point is, that there is no time to use dosmemget. Takes about > > 100mikroseconds only for the skelett. This is already the time i can > > use between two samples ! No more operations possible ! > > Last night i've experimented with the farpoke-family (i've learned this > > from a DJGPP vbe-programing-example-program). These seams the real > > answer to my question. > > Unless the buffers you need to move are very small, your conclusions > are wrong: dosmemget/put is *faster* than _farptr functions, because > it uses REP MOVSD after some initial setup. > > Section 18.4 of the DJGPP FAQ list includes a detailed description of > the different methods to move data to and from conventional memory, > and discusses the relative merits of each method; I suggest you read > it. > > > But if i know the real physical adress from an array, let a[], i > > can fill this direct by DMA. Looks much simpler. Is this cs:? > > No. If anything, it should be DS, not CS. But the only way to get > the physical address is via the VDS API, or by using a buffer in > conventional memory where all addresses are mapped 1:1, and so > physical and virtual addresses are the same. > > > Sorry about my silly questions. But, i'm a DJGPP- and DPMI-newbe. > > Therefore all these things looks not as simple for me as for you. > > Let me know better ways, please. > > A better way is to search the FAQ. It has DMA in the index. -- ___________________________________________________________________ Dipl.Phys.Gero Timann Schülerstieg 20 37081 Göttingen Germany Tel./Fax: Germany-0551-96782 EMail: geti AT mcis DOT deREMOVE_THIS geti AT spock DOT physik3 DOT gwdg DOT deREMOVE_THIS geti AT online DOT deREMOVE_THIS ____________________________________________________________________