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Re: Configuring for bare hw ia32 PC's

On Mon, 2008-05-12 at 14:17 -0400, Jonathan S. Shapiro wrote:
> > This is problematic with Ada as the language is huge and the compiler
> > adds some stuff into the code which references the runtime. Now, what
> > this stuff is, depends on what features you have available.
> Then either the Ada compiler is busted or there is some command line
> option that you need to add.

Er, no. This is the way that Ada works. There are parts of the language
which when compiled, the compiler adds in extra bits of support.

> Back up a second. You are, in effect, compiling Ada code to run on a
> bare board. The "hosted" specification of the standard C library assumes
> that you are running on top of an operating system. The "freestanding"
> version does not.
> It is okay if the Ada compiler emits things that rely on the
> freestanding version of libc. Pragmatically, it is also okay if it

Do you mean, "is it?" I would say, no that's fine. I want a basic
runtime, just not the extra bits. Unfortunately, the way the GNAT source
is built, there doesn't seem (I could be wrong) to be a way to say, I
only want this and this and this, not that.

> relies on a few additional, commonly provided OS procedures such as
> memcpy. But if it relies on much more than that you have a fairly
> fundamental disconnect in compilation models, and you need to consider
> whether the Ada compiler is generating code for the appropriate model.
> Given what you say above, I suspect that you need to start by turning
> off every Ada feature that you can, and then see what is happening.
> Can you give an example of what the Ada compiler is referencing that is
> causing a problem? If possible, also state why the Ada compiler is
> referencing this -- that is, is it being called from user-provided
> source code, or is it being called from within the Ada runtime library?

As an example, say I have an array and I want to initialise it:

package Something is
   type My_Array(1 .. 3) of Integer;

   My_Instance : My_Array := (3, 5, 2);
end Something;

The initialisation code will generate a call to memcpy. This is
something I will most probably want to include in *my runtime*.

Also, to actually get the gnat tools (e.g. gnatmake, gnatclean, etc) you
have to build the runtime. Also, I suspect that to get ASIS (which may
be necessary) you also need the runtime and the tools. :(


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