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Mail Archives: djgpp/1995/01/27/22:46:38

Date: Fri, 27 Jan 1995 20:06:55 -0500 (EST)
From: Cuthalion / Sliced Bread <enrico AT max DOT tiac DOT net>
Subject: Re: V2
To: "A.Appleyard" <A DOT APPLEYARD AT fs2 DOT mt DOT umist DOT ac DOT uk>
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu, DJGPP users list <djgpp AT sun DOT soe DOT clarkson DOT edu>


On Fri, 27 Jan 1995, A.Appleyard wrote:

> I wrote:-
> > Please! I have an important Gnu C++ program that absolutely depends on
> > knowing what addresses the text screen gets mapped to, as well as in a few
> > places needing to know what addresses the physical memory (at least the
> > lowest megabyte of RAM) gets mapped to.
> 
> kunst AT prl DOT philips DOT nl replied:-
> > Don't worry, Anthony! You can poke to your text screen using 'dosmemput
> > (buf, size, 0xB8000);'. The same routine can be used for accessing other DOS
> > locations. These routines will still work in V2. You can use the 'farptr'
> > routines as well. Pieter Kunst.
> 
> In my program I have to write to the text screen a LOT. How much longer will
> it take using this `dosmemput()' every time, than direct writing to addresses
> like I do now? I don't always write to screen as neat whole bufferfuls, but
> often one character here, one there. So I declare `unsigned short *screen'
> pointing to the start of the text screen. What are these `farptr' routines and
> where is information about them? I don't want the supermassive rewrite job on
> my program which this change will cause me. Please!!! What <is> the matter
> with having the text screen represented as always the same addresses like now??
> Ditto with knowing the graphics screen's address. This change will put a
> pickaxe handle through a LOT of my and my department's programs that I wrote!!
> 
	Well, under DPMI, stuff doesn't necessarily always fall under the 
same addresses.  Sure, with the free DPMI, stuff may be able to be hacked 
into working, but what if someone is using WinDPMI, QDPMI, or OS/2's 
DPMI?  What sounds more plausable to me would be to include a function 
that would return a pointer to, say, video graphics memory.  :)  DJ -- Is 
there any way THIS would be possible?


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