Xref: news2.mv.net comp.os.msdos.djgpp:763 From: Charles Sandmann Newsgroups: comp.os.msdos.djgpp Subject: Re: memory mapped access to video ram Date: Thu, 01 Feb 1996 20:29:17 CST Organization: Rice University, Houston, Texas Lines: 28 Message-ID: <311176fd.sandmann@clio.rice.edu> References: <4eqtk1$pm7 AT sun0 DOT urz DOT uni-heidelberg DOT de> Reply-To: sandmann AT clio DOT rice DOT edu NNTP-Posting-Host: clio.rice.edu To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp > is it still possible to access VGA ram directly under djgpp v2 ? You can access it directly using , but it won't automatically bank switch. If you have a VESA 2.0 setup (try UNIVBE if not) you can quite often establish a linear frame buffer in extended memory. > I have some old code which does exactly this under v1.xx, where I could > access all VGA ram as if it were linear ram at 0xd0000000. This only worked in non-DPMI mode under V1.x, and never worked under DPMI providers such as Windows, so it was a non-portable solution. > This code crashes when i use djgpp v2. Yes, the automatic bank switching at a single address cannot be supported under DPMI 0.9 > Does the base address have been changed ? It's no longer at a fixed address. It will change under various DPMI providers and with various video cards. > BTW, I would like to use the graphic in a fullscreen Windows 95 dos box. Either use GRX 2.0, or roll your own with a VBE 2 linear frame buffer. There is no way to get automatic bank switching under Win95, unless you can convince Mr. Bill to support a 5 year old standard called DPMI 1.0. Sorry, too busy creating new buggy proprietary code to look at standards.