Re: Can Ada by popularized faster ?

["Marin David Condic, 561.796.8997, M/S 731-96" <condicma@PWFL.COM>]

> Brian Rogoff <bpr@SHELL5.BA.BEST.COM> writes:
>Right. I think the SBC market is interesting from an Ada point of view.
>What are the main CPUs being used? Is a bare bones Ada compiler available
>for it?
>
    Well, for starters, almost any compiler that would be considered
    suitable for the SBC market would hardly be considered "bare
    bones." The quality of the code that comes out of it must be
    extremely efficient and highly reliable. Even a minor inefficiency
    starts to multiply rapidly in a chunk of code that runs once a
    milisecond. Any compiler bug that produces bad code creates the
    possibility of an error escaping into the field which can be
    *very* costly. So just the compiler itself has to be above and
    beyond what one might find acceptable, say, for teaching computer
    programming using an MS-DOS based computer.

    P.S. I am assured by folks who should know that there is no need
    to trim the Ada standard in order to get Ada to fit inside some of
    the small microprocessors in question. (At one time, yes, but
    compiler technology has improved considerably.)

    Then, because you're going to a bare piece of hardware without the
    luxury of an OS, you've got to have a cross-linker that darned
    well better be able to give you real good control of where
    anything and everything goes in memory and it has to be able to
    tell you reliably what it actually did. Surprises aren't fun! It
    needs to output IEEE symbol tables, Motorola S-Records and/or
    similar load formats.

    You need some kind of ability to load code into the card - which
    gets real dependent on the architecture of the card. We typically
    use a real time monitor of our own design that goes into startup
    ROM and communicates with a chunk of software on the host system
    which acts as our loader and our debugging system.

    You've got to have all of that just in order to play the game. We
    aren't even yet talking about bells and whistles.

    As for target processors, our engine controls are designed around
    things like the 68040 - where processor selection had to take into
    account availability of an Ada compiler. But there are lots of
    small jobs, custom one-offs, test hardware, etc. where things like
    the 68HC11 on an off-the shelf board makes the most sense.
    Micronix makes a nice little board based on this processor.
    Z-World sells a fair number of Z180 based SBCs. EMAC is another
    company with similar machines. Check out the web pages to get a
    flavor of what they're building with:

    http://www.emacinc.com/
    http://www.zworld.com/
    http://www.agt.net/public/micronix/
    http://www.claritech.demon.co.uk/


    Lots of companies make cards based on 80x86 processors, but these
    tend to be PC compatible computers which run some real time
    version of MS-DOS and tend to want to communicate with devices as
    separate cards - whereas the type of machine I'm interested in is
    the kind of thing that has one or more A/D-D/A converters a
    handful of discretes, a serial link and that's about it.

    I have not heard of any Ada compilers targeted to 68HC11, Z180,
    8051, 68HC16 or other processors you see on the web pages of the
    SBC manufacturers. That doesn't mean there aren't any - just that
    a) the SBC manufacturers aren't hawking one along with their
    development kit and b) nobody has brought to my attention any
    third-party solutions. It might not do any good simply to have, for
    example, a port of GNAT to one of these machines unless you could
    provide simultaneously all the related software that has to work
    with the output of GNAT. As you can imagine, that's not a trivial
    request.

    MDC

Marin David Condic, Senior Computer Engineer     Voice:     561.796.8997
Pratt & Whitney GESP, M/S 731-96, P.O.B. 109600  Fax:       561.796.4669
West Palm Beach, FL, 33410-9600                  Internet:  CONDICMA@PWFL.COM
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