From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,7a27b8f727dd1e47 X-Google-Attributes: gid103376,public Path: controlnews3.google.com!news1.google.com!news.glorb.com!newsrout1.ntli.net!news-in.ntli.net!news-hub.cableinet.net!blueyonder!proxad.net!feeder2-1.proxad.net!news7-e.free.fr!not-for-mail From: JCS Subject: Re: GNAT and no runtime Date: Thu, 27 May 2004 23:30:19 +0200 User-Agent: Pan/0.14.2 (This is not a psychotic episode. It's a cleansing moment of clarity. (Debian GNU/Linux)) Message-Id: Newsgroups: comp.lang.ada References: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 8bit Organization: Guest of ProXad - France NNTP-Posting-Date: 27 May 2004 23:30:40 MEST NNTP-Posting-Host: 217.108.100.6 X-Trace: 1085693440 news7-e.free.fr 22041 217.108.100.6:3701 X-Complaints-To: abuse@proxad.net Xref: controlnews3.google.com comp.lang.ada:888 Date: 2004-05-27T23:30:40+02:00 List-Id: On Thu, 27 May 2004 08:58:10 -0500, sk wrote: > JCS : > > ... > > > > So, in sumary, you are porting the GNAT run-time ? Not the whole, just a very small subset of it, just to have exceptions working. In fact, I would be perfectly happy if I didn't have to reimplement some GNAT RT functions, but unfortunately it seems that I have to. > The point I am trying to make is that to port a run-time, you need to > know what you are porting it to ! Replacing each run-time function at a > time will probably work, but why not actually step back and write the > kernel/executive to achieve your goals and then port the GNAT run-time > to your kernel's capabilities ? You probably misunderstand me, I was wishing exception because it helps to develop my kernel, it's not a functionnality of the kernel. See it as a debug feature. > > > Even if I disagree with your design, ... > > Not "my design", it is how the Intel (>= i386) chips are built. Why not > use the security/ring features of the chip if they are available ? A short answer: ring 1 and 2 in the Intel protection mechanism are almost useless, they don't provide any useful instruction that are in ring 0, but they can access all memory of user-levels apps (ring 3). Btw, the only system who use ring 2 is OS/2 and it was for some graphics stuff. I don't know any real-life OS which use ring 1. Almost all others processors have only 2 protections levels: supervisor (ring 0 on Intel) and application (ring 3 on Intel). But again it is out of topic here. > > ...it would be out of topic here. > > Discussion of OS written in Ada off topic ? Sorry, I disagree, the topic > seems appropriate to comp.lang.ada Simply, it is more OS design relative than Ada relative. Regards, JC