From:	"M. Schulter" <mschulter AT value DOT net>
Newsgroups:	comp.os.msdos.djgpp
Subject:	hello.s, anyone?
Date:	23 Sep 1997 06:03:37 GMT
Organization:	Value Net Internetwork Services Inc.
Lines:	58
Message-ID:	<607m3p$805$3@vnetnews.value.net>
NNTP-Posting-Host:	value.net
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Hi, there.

This message concerns a quest that some may find challenging, some
humorous, and some rather dubious: the road to a standalone hello.s
that can compile with

gcc -Wall -g -o hello.exe hello.s

and produce a program that will run successfully on a variety of DPMI
servers, including DJGPP's own and very distinguished CWSDPMI.

The whole question of standalone GAS programming is a FAQ soon to be
answered in the assembly tutorial taking shape as part of the DJGPP
User's Guide on DJ's site. In the meantime... 

Does anyone have ideas on how best to write standalone GAS programs
that will comply with the DPMI standard? Has anyone done it who would
be willing to talk about it or even post a program that will run with
CWSDPMI (something I haven't been able to find in a number of searches
of DJGPP-related material)?

Over a year ago, strider7 posted the program that got me started with
actual standalone GAS coding -- it works with QDPMI, but, as people
here explained, calls real mode interrupts in a very user-friendly but
less-DPMI-friendly way that causes problems with some other DPMI
servers.

One solution would be to write an interrupt handler that complies with
DPMI. 

Another, possibly, would be a Linux-style approach that calls C
functions like _printf or _puts from within a GAS file, rather like
the output from a hello.c with `gcc hello.c -S'. Could this be done in
DJGPP? I notice that hello.c produces an .exe about 20K longer than
one of my hello.s programs with QDPMI-permitted interrupts, and wonder
if stdio.h is making the difference. Is it possible to 'call ___main'
within a handcoded hello.s?

In short, maybe this might be a soon-to-be-a-FAQ, given that the next
installment of the DJGPP User's Guide on GAS programming is pending --
but I'd be curious to see simple, not so simple, or even obfuscated
solutions to the enigma of a standalone hello.s (or hello.S --
preprocessor not excluded).

Any ideas?

Most appreciatively

Margo Schulter
mschulter AT value DOT net

(To reply, please remove the extra . in my default address)

- Raw text -