> > > but then virtual-86 mode is set and I can no loger use 32bit real-mode > > > pointers! > > IF you need PM from V86 there is VCPI. > Protected mode isn't the same as flat real mode.
NO, but there is no absolute need to use flat [un]real mode. > flat-real mode, VCPI and DPMI work and how they deal with other > previously loaded systems to avoid collisions? DPMI is not very relevant for real mode drivers. The important quetions are: - Do we have a 32-bit CPU ? - Real or V86 mode ? - Do we have an XMS host, version 2 or 3 ? - If V86, do we have VCPI at least (if not, we are most likely inside NTVDM) ? > mentioned "if you want PM, you have VCPI", I think, meaning if I > wanted to access PM memory. NO. You need VCPI if you want to run your own PM code but find yourself in V86. The XMS host as well as BIOS or EMM386 will temporarily switch to PM or unreal for you when memcopying for you. > Only I wish I knew more about VCPI. Google for "VCPI.DOC" or "VCPI.ZIP" or "VCPI spec" or so. FYI: VCPI is the "award winning standard" from 1988 :-D FYII: forget or postpone VCPI, get your driver working using XMS and INT $15 first. > it will probably be enough to just rely on XMS functions for now. Exactly. > One doubt I have about XMS functions is this: the XMM specification states > that if I lock some memory, I must unlock it as soon as possible. How soon is > that? Just before unhogging it should be fine. > would be important to keep it locked for as long as the driver is running Do it, hog and lock your XMS at driver start, and unlock and unhog just before driver removal. > Can I keep memory locked like for the whole time one process is running > (i.e.: half an hour)? Even 1 year :-D > How bad is that? NOT at all. > can read Assembly, you can also look at the > source code of HIMEMX, JEMM and HDPMI. And FASM of course (hogging physical memory from BIOS or XMS host), beware that the unreal mode used by it is VERY special and unique. :-) -- ~~~ wow ~~~ ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
