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Xref: sserve comp.os.386bsd.apps:1069 comp.os.linux.misc:11325 Newsgroups: comp.os.386bsd.apps,comp.os.linux.misc Path: sserve!newshost.anu.edu.au!munnari.oz.au!goanna.cs.rmit.oz.au!aggedor.rmit.EDU.AU!harbinger.cc.monash.edu.au!msuinfo!agate!ihnp4.ucsd.edu!library.ucla.edu!csulb.edu!csus.edu!netcom.com!hasty From: hasty@netcom.com (Amancio Hasty Jr) Subject: Re: DOOM for X Message-ID: <hastyCMnA5y.Mpw@netcom.com> Organization: Netcom Online Communications Services (408-241-9760 login: guest) References: <2lo4m0$sdt@bosnia.pop.psu.edu> <SJA.94Mar12174713@gamma.hut.fi> <2m0h7a$3ck@u.cc.utah.edu> Distribution: inet Date: Mon, 14 Mar 1994 07:58:45 GMT Lines: 32 In article <2m0h7a$3ck@u.cc.utah.edu> terry@cs.weber.edu (Terry Lambert) writes: >In article <SJA.94Mar12174713@gamma.hut.fi> sja@snakemail.hut.fi (Sakari Jalovaara) writes: >(1) You can't necessarily map memory from the display adapter > directly. There is often a "window" which you must use to > communicate with display memory that would be used instead. > Not sure what the above means. It is almost correct. In the case of svga, most cards support the concept of banking, so that a program can map the vga's memory into the user space. Some support 64k banking or 128k banking at a time. Full addressing of the card is done by specifying a "vga bank" and the offset into the start of the vga mapped address. BTW: vga banking is not really a standard so it varies from svga implementation to svga implementation. The S3 801/982/864/928 as well as a few other vga cards are fully capable of mapping their entire video ram into the user space;hence, there is no need for "vga banking". The S3 cards have registers which tell the card where to map the video memory to. Amancio -- FREE unix, gcc, tcp/ip, X, open-look, interviews, tcl/tk, MIME, midi, sound at freebsd.cdrom.com:/pub/FreeBSD Amancio Hasty, Consultant | Home: (415) 495-3046 | e-mail hasty@netcom.com | ftp-site depository of all my work: ahasty@cisco.com | sunvis.rtpnc.epa.gov:/pub/386bsd/X