Message-Id: <200008040950.FAA10032@delorie.com>
Date: Fri, 04 Aug 2000 12:53:21 +0200
To: trzy AT powernet DOT net
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From: "Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il>
CC: djgpp AT delorie DOT com
In-reply-to: <HTri5.9460$Z6.341057@newsread1.prod.itd.earthlink.net> (message
	from Bart Trzynadlowski on Fri, 04 Aug 2000 04:45:27 GMT)
Subject: Re: Buffers
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> From: Bart Trzynadlowski <trzy AT powernet DOT net>
> Newsgroups: comp.os.msdos.djgpp,comp.lang.asm.x86,alt.lang.asm
> 
> I need to use certain interrupts in my assembler modules which I link in
> with DJGPP, but there are problems when passing buffer addresses.
> 
> mov ah, 9
> mov edx, msg
> int 0x21
> 
> The above works great.

Probably on Windows only.  On plain DOS, it will not work.  The reason
is that the buffer where you put the message text is in protected-mode
memory, above 1MB mark, whereas DOS real-mode addressing can only
address the first MByte (give or take extra 64KB).

Please read sections 18.1, 18.2, and 18.4 in the DJGPP FAQ list
(v2/faq230b.zip from the same place you get DJGPP), it explains how to
call real-mode services from DJGPP programs.  Section 18.5 might also
be a useful reading.

If something is not clear after you read the FAQ, please post specific
questions on comp.os.msdos.djgpp.