Re: Ada for microcontroller?

Re: Ada for microcontroller?

[Robert I. Eachus]

In article <1993Jul23.123338.26421@hellgate.utah.edu> matwood%peruvian.cs.utah.
edu@cs.utah.edu (Mark Atwood) writes:

   > I'm starting on a new project that will be running on an embedded
   > controller.  Looking through the list of Validated Ada compilers,
   > I noticed that there were several for the MIL-STD-1750 processor.
   > If someone could fit Ada onto that (begin personal opinion)
   > clunky, obsolete at birth, small, slow, expensive piece of ****
   > (end personal opinion) why not for a 8051, 6805/08/11. Z80, etc.,
   > based microprocessor?

    Right now the situation seems to be that if there is interest AND
a floating-point instruction set (which maybe supported through traps
and software emulation) there will be a validated Ada compiler,
otherwise not.

   This can, of course, be traced back to the no subsets policy, even
though it was never intended to force this situation.  I could
probably cobble up a portable floating point library that would work
on even 8-bit microcontrollers (if they have enough address space!),
but this is not the right solution.  A much better resolution to the
issue would be to validate a compiler (under AI-325) with NO floating
point types and no floating-point arithmetic.  A demonstration that it
can be done, and of how to do it, would work wonders.

--

					Robert I. Eachus

with Standard_Disclaimer;
use  Standard_Disclaimer;
function Message (Text: in Clever_Ideas) return Better_Ideas is...

Re: Ada for microcontroller?

[Will Deatrick]

 RE>Ada for microcontroller?
In <1993Jul23.123338.26421@hellgate.utah.edu>, Mark Atwood writes:

> I'm starting on a new project that will be running
> on an embedded controller. Looking through the list
> of Validated Ada compilers, I noticed that there
> were several for the MIL-STD-1750 processor.
> If someone could fit Ada onto that (begin personal
> opinion) clunky, obsolete at birth, small, slow, expensive
> piece of **** (end personal opinion) why not for a 8051,
> 6805/08/11. Z80, etc., based microprocessor?

About a year ago, I ran into this same problem on a DoD program. We planned to
use a small, cheap 8031 as a Built-In Test (BIT) controller. The processor had
to be small and cheap since it would be present on every hardware module, but I
could not find an Ada compiler for the 8031.  I got several responses to my
queries on comp.lang.ada and by talking to vendors, and the explanations for
the lack of Ada compilers for these processors included:

1) Getting all of the Ada language to run in the 8 or 16-bit address
   limitations typical of smaller processors is difficult.

2) Even though many of the advanced constructs (tasking, generics) may not be
needed 
   for a small application, you can't pass the ACVC tests without them and no
one
   wants a non-validated Ada compiler.

3) It is possible to get an exception to write a small amount of code in
another
   language, even on DoD programs.

4) If the processor and the code are small, then hardware availability down the
   road becomes a more important issue than software maintenance costs.

5) The market for Ada on small processors is not large enough to justify the
expense.

Someone did mention the MC68302 series microcontroller as a possibility as it
had a low chip count and an Ada compiler.  I did not get any farther in my
search as that part of the program was cut.  Unless things have changed within
the last year, you may be forced to start brushing up on your C and assembly.
:-)

Regards,

Will Deatrick
deatrick@sdfvax.rc.trw.com