Re: Isn't this in favour of Ada??

[Robert A Duff <bobduff@shell01.TheWorld.com>]

Marin David Condic <nobody@noplace.com> writes:

> Well, if I thought about it long enough, I could probably figure out
> some way of disconnecting the interrupt from the code it has to trigger
> using only existing Ada mechanisms. What I fear is that it would
> introduce either too much inefficiency or not provide for
> uninterruptability that may be needed by an ISR. I suppose it wouldn't
> hurt too much if you actually shielded the ISR beneath some hardware
> abstraction layer & kept it small, providing most of the "Real" work has
> to happen above it. (Let it grab data and propogate a message of some
> sort?) But then you're really not making a provision to run all of the
> software for an embedded system on some workstation platform in an
> off-line way.
> 
> It would be better with a language mechanism, but I don't know if it is
> either too complicated or of too narrow an interest to be worth a
> language update.

The problem you're talking about is "How to deal with cases where you
need to write different code for different platforms."  If the language
is well designed, and the compilers aren't too buggy, this will happen
fairly rarely.  Interrupt handling is inherently platform specific, so
this is one case where you'll need platform-specific code.  The usual
solutions are to use a preprocessor of some sort, or to write different
versions of the same source file, and have the build process select
among them.

So I think no interrupt-specific language mechanism is warranted here.

I agree with you that it would be nice to have a way to trigger an
interrupt under program control.

- Bob