From:	Marc Singer <nbn.nbn.com!sapien!elf>
Subject:	Re: Linear frame buffer emulation.
To:	nbn.nbn.com!sapien!sun.soe.clarkson.edu!djgpp (DJGPP List Alias)
Date:	Mon, 9 Oct 1995 09:55:52 -0700 (PDT)

According to Charles Sandmann:
> 
> > djgpp v1.x supported some kind of linear frame buffer emulation, having 
> > the videoram at 0xd000000 using paging etc... Does djgpp v2 support this ?    If not are there any __dpmi_ functions that i can use to setup
> 
> No.  V1.x doesn't support it under DPMI environments (ie windows, etc) either
> 
> > or do I have to code this all fro scratch. Perhaps someone has coded such 
> > a page fault handler and would like to share his code with others ?:)
> 
> It would be virtually impossible to provide this sort of access under a
> DPMI 0.9 host.  This could be done with a DPMI 1.0 host - but the only
> one out there is currently 386MAX.  The source for CWSDPMI is available,
> so you could add some custom extension to it for this purpose.
> 

FYI Microsoft (allegedly) supports a linear frame buffer in their new
Game SDK.

For those don't know about the Game SDK, it is a whole set of video
and audio drivers for Windows 95 that Microsoft is writing so that a)
developers don't have to be at the mercy of several crummy driver
writers (one stop shopping), b) inefficiencies in the Windows driver
designs are circumvented (both video and audio have some glaring
flaws), c) DOS games can be ported more easily given a simple, fast
hardware access API.

Marc Singer

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