Re: Is an RTOS Required for Ada?

[Marin David Condic <condicma@bogon.pwfl.com>]

Tramse wrote:
> 
> I have an application in which Ada95 is required.  The target microcontroller
> is the Motorola 68336.  It a real simple application, it only needs to
> read/write to fixed addresses (ports/data) and respond to a interupts.  We have
> a real fast boot up requirement and small RAM resource (7.5K) and can't afford
> the boot time and RAM requried for a RTOS.
> 
> Can we use Ada and compile direct to 68K code without using an RTOS (like we
> could in C)?
> 
Its done all the time. However, you have to ask that question of your
particular compiler vendor. Just because it generates code for a 68336
(is there a compiler for this target?) doesn't mean it won't make code
that generates calls to some presumed OS. For example, GNAT will
generate calls to the OS to get tasking services done, but you can get
the RTEMS software which will provide for those primitives without the
presence of an OS (Unless you want to call RTEMS an OS. It may be more
accurate to describe it as a "Run Time Kernel" or "Run Time Support" -
not an RTOS - but lets not start that debate.) Some versions of GNAT
have the ability to generate "pure" code which makes no calls to any
runtime kernel (called GNORT), but naturally, you loose support for some
features. (I've never seriously looked into GNAT/RTEMS/GNORT because
I've never had an app where this seemed to be a fit. I can't tell you
how easy/hard it would be to use any of this.)

There are other vendors such as Aonix and Green Hills who have compilers
aimed at embedded targets and they probably have solutions as well.
There's nothing in Ada to prevent this - you just have to check how it
is done for the compiler/target combination.

Have you already acquired a compiler? If so, posting the brand & version
may help in getting more detailed information on how to go about doing
what you want to do.

MDC
-- 
Marin David Condic
Real Time & Embedded Systems, Propulsion Systems Analysis
United Technologies, Pratt & Whitney, Large Military Engines
M/S 731-95, P.O.B. 109600, West Palm Beach, FL, 33410-9600
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