X-Authentication-Warning: delorie.com: mail set sender to djgpp-bounces using -f From: Hans-Bernhard Broeker Newsgroups: comp.os.msdos.djgpp Subject: Re: Why the call instruction points 2 bytes before to the real start sub-routine ? Date: 2 Nov 2005 17:53:23 GMT Lines: 30 Message-ID: <3sscojFptcqiU3@news.dfncis.de> References: <000201c5dfb4$1e997d10$2432a8c0 AT dcueva> X-Trace: news.dfncis.de TBJwg5jRJ4ascG7OtjckPgHUk1ao5qm4NIOAYbAmIq28f/xbGow3bq9j+Z X-Orig-Path: not-for-mail To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Reply-To: djgpp AT delorie DOT com Diego Cueva wrote: > com file not are my final objective. My Objective is creating a small > operating system to educational purposes, and I need compile C programs > with GCC that can execute in booting time. In that case, .com files are not just not your final goal, they're not even likely to be particularly useful as a stepping stone getting there. Code compiled by the DJGPP version of GCC strictly assumes a DPMI-like environment. You'ld have to recreate basically all of a DPMI server, and large parts of DOS, before this code will run reliably. To get an idea of what that means, have a good look at the CWSDPMI sources. It might end up being easier to embed FreeDOS, CWSDPMI and your program into a single binary image, instead. > To this moment I have a IPL program with a group small routines in > assemble compiled/linked with "as/ld". This is working fine. Working fine in what kind of environment? Called from DOS? > But link that with C compiled code is the WALL to climb now. Exactly. Wherein "WALL" is not just some bedroom wall or something --- it's more like the Eiger North side. -- Hans-Bernhard Broeker (broeker AT physik DOT rwth-aachen DOT de) Even if all the snow were burnt, ashes would remain.