Re: fixed point vs floating point

[gwinn@res.ray.com (Joe Gwinn)]

In article <3484D37E.E68@nospam.flash.net>,
Ken.Garlington@nospam.computer.org wrote:

> Joe Gwinn wrote:
> > 
> > Portability is less important than workability.  And, we were always
assured that use
> > of Ada guaranteed portability.  Apparently that was a lie; we also need to
> > be Ada experts to achieve portability?  Just like all other languages?
> 
> In my experience - absolutely. If you assume that X is portable just
> because it happens to work when processed with a particular vendor's 
> implementation of X, you are probably going to be disappointed.

Yep.  Absolutely.  I think I made just this point three or four times, but
it's become hard to follow.

In truth, I was just twisting Robert's tail.  With great success, too. 
Snapped the hook right out of my hands.  He didn't catch the irony at all,
answering with yards of riposte text.   After all that abuse, it was time
to give as well as to get.


> (Just to save you grief in the future, feel free to plug in any of the
> following for
> X: Ada, C++, Java, POSIX, CORBA, etc.)

Yep.  Don't forget fortran and assembly, or COBOL.


> > Well, you are obsessing on the fact that I don't recall ten years later
> > all the details of how to do fixed point arithmetic in Ada83, which we
> > never used except to test.  And, you are proving my basic point, that with
> > all that user-supplied information, Ada83 should be able to handle fixed
> > point arithmetic.  This is just some added information, clearly not
> > absolutely required information, because Ada95 no longer always requires
> > it.
> 
> Ada no longer requires it for trivial cases. For many intermediate
> calculations
> of this type, you still have to explicitly specify the resulting type.

The original point of departure was my comment that the die was cast in
the bad old days of Ada83 compilers that didn't handle fixed point
arithmetic well enough for the ordinary programmers to use without greater
difficulty and danger than they were willing to undertake.  Perhaps, if
they were only smarter, or in less of a hurry, or better educated, they
would have seen the error of their ways.  Sadly, it was not to be.  Thus
have many technologies died.

Now, with floating point hardware almost universal, the issue is moot.


> > And, I really don't see why it's necessary to deny the failings of
> > compilers that have been obsolete for at least a decade, for a now
> > superceeded language.  Surely we can find something more current and
> > relevant to worry about, to argue about.
> 
> I'm confused. If the behavior you described is not relavant, why did you
> bring it up?

Because Robert attacked me simply for saying that there was a problem back
then.  My point here is that I don't know why he cared that much about
such an ancient issue.  Never mind the now fuzzy details.  It very much
has the flavor of refighting yesterday's war.  Tiresome, and quite
pointless.  

It's not that we can't find something current to argue about, one where
the outcome could have a material effect on something.


Joe Gwinn