X-Authentication-Warning:	delorie.com: mailnull set sender to djgpp-bounces using -f
From:	"Andrew Fairburn" <a DOT j DOT fairburn AT durham DOT ac DOT uk>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Real mode callbacks + assembler code
Date:	Tue, 4 Dec 2001 15:18:29 -0000
Organization:	University of Durham, Durham, UK
Lines:	26
Message-ID:	<9uipbl$rse$1@sirius.dur.ac.uk>
NNTP-Posting-Host:	a-cws224.dur.ac.uk
X-Trace:	sirius.dur.ac.uk 1007478965 28558 129.234.53.224 (4 Dec 2001 15:16:05 GMT)
X-Complaints-To:	usenet AT durham DOT ac DOT uk
NNTP-Posting-Date:	Tue, 4 Dec 2001 15:16:05 +0000 (UTC)
X-MimeOLE:	Produced By Microsoft MimeOLE V5.50.4133.2400
X-Priority:	3
X-Newsreader:	Microsoft Outlook Express 5.50.4133.2400
X-MSMail-Priority:	Normal
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

ive been having some problems getting this to work, i think ive managed to
get the real mode program to access the correct reflected segment and offset
for my protected mode function, but it then crashes without error messages.
ive been looking at the callback specification, and the hook written in the
example:-
cld
 lodsw  ; Get real mode ret IP
 mov es:[di.RealMode_IP], ax
 lodsw  ; Get real mode ret CS
 mov es:[di.RealMode_CS], ax
 lodsw  ; Get real mode flags
 or ax,1 ; St carry flag
 mov es:[di.RealMode_Flags], ax
 add es:[di.RealMode_SP], 6
 mov es:[di.RealMode_AX], 5
 iret

as far as i can tell this moves the es:di reg into cs:ip reg. Unfrotunately
i cant get this syntax to compile, it tells me there is 'junk' after the es:
I need a call back function, similar to this, which also puts 0:0 in the
es:di field of the callback data structure, can anyone help??? :)

Thanks,
andy.

- Raw text -