Date: Wed, 4 Nov 1998 11:16:17 +0200 (IST) From: Eli Zaretskii X-Sender: eliz AT is To: Jeramie Hicks cc: djgpp AT delorie DOT com Subject: Re: DJGPP-written OS In-Reply-To: <363e3b5e.180409204@newshost.cc.utexas.edu> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: djgpp AT delorie DOT com On Mon, 2 Nov 1998, Jeramie Hicks wrote: > I'm toying around with writing a barebones OS (initially being able to > boot and walk around a hard drive only). I'd like to use DJGPP to > write the command interpreter, but I'm not sure which DOS interrupt > handlers I need to write. What interrupts does a DPMI provider or the > DJGPP stub need initially provided to function properly? The interrupt handlers are not usually part of the command interpreter, they are part of the operating system itself. The command interpreter is just a user interface to basic operations like moving around the directory structure, managing files, running programs, etc. So it is not entirely clear what are you asking about. > I mean, I can figure out what DOS functions my own code needs, but > what about the stub and DPMI program? Clearly, the answer is in the sources. I suggest to take a good look at the files in djlsr201.zip that pertain to the startup code. The src/stub/stub.asm file and the src/libc/crt0 directory should be the starting point, and then look up any library functions called by crt0.S and crt1.c. As for the DPMI provider, if you want to use CWSDPMI, look at its sources (v2misc/csdpmi4s.zip on SimTel.NET). Other providers will of course use somewhat different set of DOS/BIOS calls.