Message-ID: <39A3D9CE.AC8E7538@maths.unine.ch>
Date: Wed, 23 Aug 2000 16:03:58 +0200
From: Gautier <gautier DOT demontmollin AT maths DOT unine DOT ch>
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Subject: Re: How do I customize libc for custom OS?
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To: djgpp AT delorie DOT com
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Tobias Skytte:

> hmm. yes Ada95 definently sounds interresting, but before I download GNAT
> (22 mb on a slooow connection) can you tell me this:

From ftp://ftp.gwu.edu/pub/ada/ez2load/ you can d'load

FILE: djgpp201.zip
FILE: gnat3101.zip
FILE: gnat3102.zip
FILE: gnat3103.zip
FILE: gnat3104.zip
FILE: gw_gnat.zip
(grabbed from install script)

plus install.scr and ginstall.exe . The whole is < 6 * 1.44MB.

> 1) would I still need to modify the libc (since GNAT depends on djgpp) to
> make my OS? or does GNAT not use libc at all?

GNAT uses libc, but it provides the pragma no_run_time that eliminates
the run time system - I've just read it in the GNATList mailing list
http://lyris.seas.gwu.edu/cgi-bin/lyris.pl?enter=gnatlist&text_mode=1
gnatlink has certainly options for replacing libc .

> 2) is Ada95 often used to devellop OS's? is it easier to 'modify' it to work
> with a custom OS than other compilers (like djgpp or FPK etc etc)?

On some embedded systems (e.g. systems you meet in the sky or space) the
OS is all-Ada. It is possible to customise it a lot and in a relative
standard way. You can also program advanced things without allocator/deallocator
(sometimes it is required for robust mini-OSes) since Ada handles complex,
even unconstrained structures just like an integer or a character.

The best is to ask the gurus on GNATList or on news:comp.lang.ada .

HTH
______________________________________________________
Gautier  --  http://members.xoom.com/gdemont/gsoft.htm