Re: GNAT and no runtime

[rolf.ebert_nospam_@gmx.net (Rolf Ebert)]

JCS <SANS.SPAM@MERCI.FR> wrote in message news:<pan.2004.05.25.20.56.53.697296@hejmreto.net>...
> Hi,
> 
> I'm trying to create a toy-OS in Ada and I'm still in the very begining
> yet.

The project sounds ambitious, but it can be a lot of fun.

I cannot answer your detailed questions.  I once had a look at the
GNAT runtime, too.  A good starting point is the private part of
system.ads and the corresponding explanations in targparm.ads.

Start slowly putting more and more things to your runtime.  You almost
certainly already have system.ads and some dummy (i.e. empty)
libgnat.a.  That is needed even in the case of No_Runtime.   You can
easily add things like a-uncconv, s-stoele, interface, s-maccod.  They
all just need to be present at compile time, but aren't needed at link
time (OK, the .ali's are, not the .o).

I highly recommend the free book "A Detailed Description of the GNU
Ada Run Time" at http://www.iuma.ulpgc.es/users/jmiranda/gnat-rts/index.htm.
 Things have changed a bit in gcc-3.4, but that are details.

Replace the pragma restriction (No_Runtime) in gnat.adc by all the
detailed restrictions that you can find.  Then remove the restriction
that you don't want to enforce anymore and see what runtime support is
needed and add it to your project.

HTH

     Rolf