quality / availability of gnat

quality / availability of gnat

[Martin Gangkofer]

I am planning to use gnat as cross compiler for an embedded application
based on LynxOS operating system. The application  demands high
performance, this means the compiler shall produce good quality code.

(1) Do you know wether there is a complete (and supported) port of gnat
    to LynxOS.

(2) How good is the quality of gnat in terms of performance of the
    generated code?

(3) What are the host resource requirements when using gnat?

(4) Is gnat suitable for use in a big projects 100,000 ... 500,000 SLOC?

Thank you for your response,
Martin
--
Martin Gangkofer, System Engineer
ESG Elektroniksystem und -Logistik GmbH, Dept.EF-E
Einsteinstrasse 174, D-81675 Muenchen
eMail: mgangkof@esg-gmbh.de


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Re: quality / availability of gnat

[Pascal Obry]

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You should certainly send this request to sales@gnat.com

Pascal.

Martin Gangkofer <mttg@my-deja.com> a �crit dans le message :
7mcmjb$llj$1@nnrp1.deja.com...
> I am planning to use gnat as cross compiler for an embedded application
> based on LynxOS operating system. The application  demands high
> performance, this means the compiler shall produce good quality code.
>
> (1) Do you know wether there is a complete (and supported) port of gnat
>     to LynxOS.
>
> (2) How good is the quality of gnat in terms of performance of the
>     generated code?
>
> (3) What are the host resource requirements when using gnat?
>
> (4) Is gnat suitable for use in a big projects 100,000 ... 500,000 SLOC?
>
> Thank you for your response,
> Martin
> --
> Martin Gangkofer, System Engineer
> ESG Elektroniksystem und -Logistik GmbH, Dept.EF-E
> Einsteinstrasse 174, D-81675 Muenchen
> eMail: mgangkof@esg-gmbh.de
>
>
> Sent via Deja.com http://www.deja.com/
> Share what you know. Learn what you don't.

Re: quality / availability of gnat

[Markus Kuhn]

|> Martin Gangkofer <mttg@my-deja.com>:
|> > I am planning to use gnat as cross compiler for an embedded application
|> > based on LynxOS operating system. The application  demands high
|> > performance, this means the compiler shall produce good quality code.

|> > (1) Do you know wether there is a complete (and supported) port of gnat
|> >     to LynxOS.

I don't know about LynxOS, but ACT does offer commercial support for
a couple of embedded real-time operating systems, including for example
VxWorks, and some avionics applications of significant complexity built
with VxWorks and GNAT are already flying on board of various US military
aircraft.

|> > (2) How good is the quality of gnat in terms of performance of the
|> >     generated code?

It is usually possible and relatively straight forward to produce
with GNAT the exact same sequence of machine instructions that
the GNU C compiler would produce from the corresponding C program.
Sometimes GNAT does implement things internally in a way that
surprises beginners a bit (especially related to how variable-length
objects are treated on the stack, where a LISP/Perl/Java/Python
programmer might intuitively expect a heap allocation). These things
can however usually easily be spotted by inspecting the "-gnatdg" output,
and the intermediate (low-level Ada-style) code that you see there
is converted into machine code very similar to how the same C code
would be compiled. If you use very basic Ada features that are
equivalent to C's features, you get the same code. If you use high-level
features of Ada (exceptions, unbounded arrays, tasking, etc.) that are not
available in C, you have to test whether the code produced from these
high-level features meets your performance requirements.

I have done encryption and image processing applications with GNAT and
the performance was very comparable to what I get with similar code
in C (or at least not more than 10-20% worse, and that is just a few
months in Moore's law).

|> > (4) Is gnat suitable for use in a big projects 100,000 ... 500,000 SLOC?

I hear that it is successfully being used in several projects of this
size by ACT and ACT-Europe customers.

Markus

-- 
Markus G. Kuhn, Computer Laboratory, University of Cambridge, UK
Email: mkuhn at acm.org,  WWW: <http://www.cl.cam.ac.uk/~mgk25/>