Re: Ada to C translator for small microcontrollers

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

On 12-03-27 23:13 , kalvin.news@gmail.com wrote:
> tiistaina 27. maaliskuuta 2012 20.22.07 UTC+3 an...@att.net
> kirjoitti:
>> Full language translators are mostly used to move a project away
>> from one language to another more accessable language. So, why use
>> Ada in the first place.

Because it is so much better than C, of course :-)

I know of more than one project that used Ada as a high-level design and 
specification language, and then implemented the design in some 
lower-level language (in one case, an assembly language). In some cases, 
the Ada code was complete and runnable and could be used as a test 
oracle for the lower-level implementation.

> This is a very valid question. How large a software project needs to
> be in order to benefit from implementing it in Ada?

IMO, basically there is no lower limit, with the possible exception of 
the null program.

> Is it only a one
> person prjoect, two person project or project involving a small team.
> Why bother with Ada as we already have (free) C compiler avaiable.

We also have a free Ada compiler available, for many platforms -- but 
not for many small processors, I grant.

But many projects developing in C for microcontrollers use non-free, 
commercial compilers, IDEs, and other expensive tools (in-circuit 
debuggers, etc.) The question IMO is not whether there is a benefit from 
using the Ada language; the question is if the benefit can be 
convincingly quantified in money and schedule terms.

> If the project is a small one, and you don't have to share the code
> with others, C is just fine.

No! C is a like a Model-T Ford that for some strange reason is allowed 
on modern roads. You can survive and not be too uncomfortable on short 
trips, but you should really consider changing to a better car.

IMO the only reasons that would make me use C instead of Ada are:
- No Ada compiler available within my budget
- Need to use large C libraries/APIs for which no Ada binding exists.

> I do realize, that it might be almost impossible to produce efficient
> C source translation for corresponding Ada, compared to corresponding
> assembly.

It is true that C does not provide all the features of assembly 
language, for all that it is called a "portable assembler". But I'm not 
sure that this would be a large handicap for an Ada compiler that uses C 
as an intermediate language (like the SofCheck one).

The C level could be a performance bottleneck if one wanted to support 
wider numbers in Ada than the C compiler supports -- for example, an Ada 
64-bit Long_Integer with a C compiler that supports only 32-bit integers 
-- but this is a marginal effect, I think.

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
       .      @       .