Porting Ada (Gnat/gcc)

Porting Ada (Gnat/gcc)

[Alun Moon]

I'm planning a project (possibly an undergraduate/masters one) to port
Ada to a new processor.

We have a processor simulator we use in teaching, with a simple
architecture.  I'm planning a port of the gcc back end for assembler
generation from gcc (along with assembler and linker ports).

My colleague's eyes lit up at the thought of an Ada port (we can use
this platform for teaching embedded systems).

Assuming I have
	gcc backend (assembler generation
	as port
	ld port
from gcc and binutils

What do I need to do to have an Ada port?
Are there library sources that need porting?

many thanks

Dr Alun Moon
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Dr Alun Moon            Senior Lecturer in Computing
                        School of Computing and Mathematics
alun.moon@unn.ac.uk     D.204 Ellison Building
(0191) 227 3643         University of Northumbria at Newcastle
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Re: Porting Ada (Gnat/gcc)

[Stefan Skoglund]

Alun Moon wrote:
> We have a processor simulator we use in teaching, with a simple
> architecture.  I'm planning a port of the gcc back end for assembler
> generation from gcc (along with assembler and linker ports).
> 
> My colleague's eyes lit up at the thought of an Ada port (we can use
> this platform for teaching embedded systems).

It exists a realtime OS which runs on a MIPS simulator.
Only problem i can't remember the name just now 8-) ...

It is a simple matter of configuring gcc, gas and binutils
for mips-*-* .

The simulated machines locks a little bit like an early digital
MIPS-based workstation like a 3100

Re: Porting Ada (Gnat/gcc)

[Stephen Leake]

Alun Moon <alun.moon@unn.ac.uk> writes:

> I'm planning a project (possibly an undergraduate/masters one) to port
> Ada to a new processor.
> 
> We have a processor simulator we use in teaching, with a simple
> architecture.  I'm planning a port of the gcc back end for assembler
> generation from gcc (along with assembler and linker ports).
> 
> My colleague's eyes lit up at the thought of an Ada port (we can use
> this platform for teaching embedded systems).
> 
> Assuming I have
> 	gcc backend (assembler generation
> 	as port
> 	ld port
> from gcc and binutils
> 
> What do I need to do to have an Ada port?

The GNAT source, and a tasking OS that can interface to the GNAT
tasking run time library.

> 
> Are there library sources that need porting?

Yes, they are included in the GNAT source. The only part that should
need any work is the tasking stuff.

If you don't mind a non-tasking Ada subset, you have very little work
to do.

Oops, forgot to mention floating point; is that in hardware, or
handled by the gcc port already? Again, you can get by with an Ada
subset, but it's harder to define a non-floating point subset than a
non-tasking one.

The GNAT documentation does _not_ talk about how to port to a new
processor. Even the GNAT support team is not very helpful in this area
(I'm a paying customer, but they wanted a _lot_ of money to do a port
to a new processor). You have to be able to read the GNAT makefile and
figure things out. If your processor is 32 bits with IEEE floats, it
should not be hard at all. Mine is 16 bits with 16 bit chars, and it's
a pain!

-- 
-- Stephe

Re: Porting Ada (Gnat/gcc)

[B. Douglas Hilton]

From what I have read, you also need a working gnat to
build gnat ?! In this case, you are going to have to
cross-compile gnat for your platform in order to
bootstrap it.