From: "KECSKEMÉTI BALÁZS" <balazs AT tiszanet DOT hu>
Newsgroups: comp.os.msdos.djgpp
Subject: Q: playing with selectors
Date: Sat, 21 Nov 1998 18:22:36 +0100
Organization: MatavNet
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

Hi all,

Some time ago, i posted a question to this newsgroup,
but you misunderstood that, so i ask it again, but in other
words :

- what kind of selectors do segment registers contain under
DJGPP? I programmed in pure assembly with a DOS extender
for a while, and under that DS,ES,FS,GS contained specific values,
eg. ES contained a selector with base 0 and 4GB limit, FS pointed
to the video memory (A000h) with 64K limit etc. Does DJGPP offer
such things? (i guess not)
( i know about _dos_ds)

- Let's say that i set up a selector in FS (in an external assembly
function),
which points to A0000h, and has 64K limit. Then, can i use FS in other
assemby
functions? Later, will it contain what i have put in it, or some other
functions
( like printf ) may change FS (or ES/GS)? And if i change FS in my function,
will other functions crash?
The reason for why i ask this is that i don't wanna push/load/pop segment
registers in every single assembly function.

Thanks for all who will answer, and had answered before...

Balazs Kecskemeti
balazs AT tiszanet DOT hu