Re: Nice to have feature in upcoming Fortran compilers...

In article <jExle.35000$J25.25646@xxxxxxxxxxxxxxxxxxxxxx>,
Charles Russell <SPAMworFREEwor@xxxxxxxxxxxxx> wrote:

> Richard E Maine wrote:
> It would make Fortran essentially
> > unimplementable on many of the architectures that used to be quite
> > common.
>
> I was under the impression that you could do it in software on any
> hardware, though perhaps inefficiently. If this imposed a burden on
> hardware vendors to make it efficient, there would be precedents. At
> one time it was asserted that the fortran language itself was unfairly
> biased in favor of IBM hardware.

Well, in the earliest days, it wasn't a standard at all, but a (small)
set of implementations, the first ones being on IBM hardware, so in
some sense that is a pretty safe statement. It isn't clear that all the
things that one hears are actually true (particularly when it comes to
subjective matters like "unfairly biased"). I was a bit young in '54 to
even be able to say "unfairly biased", so I've no first-hand data.

Of course, the first standards weren't started from scratch, so there
were almost bound to have been some elements of inheritance from early
implementations. How well the abstraction was done in the early
standards, I won't judge too much, though I'll note that it apparently
was done well enough so that there were quite a lot of implementations
on quite a lot of machines with, among other things, wide variation in
word sizes (not to speak of machines where the concept of a word was a
bit vague).

If it had been too tied to IBM hardware, we probably wouldn't be
discussing it right now. There are still lots of machines around that do
the old IBM floating point format, and Fortran even runs on them. But in
terms of Fortran, that's a pretty small niche today. (Some might
consider all of the Fortran market to be a niche - if so, that's a niche
of a niche).

Heck, at the moment, one might say that the Fortran standard is biased
against the old IBM floating point. There is a whole chapter ("clause"
in ISO-speak) on IEEE stuff that doesn't "fit". Sure that is all
optional, but I'd still call that a bias in that it looks bad if a
vendor has to say that they are omitting a whole chapter of the
standard, even if the standard itself allows that.

Oh, my "essentially" was to cover the case of "many things are possible
if you want to emulate the whole machine in software". I tossed it off
with a single word because I don't think it realistic. Yes, it can be
done. No, I don't think it is going to happen.

In my opinion, the odds of actually mandating an integer of exactly 8
bits are low. They clearly aren't zero, but I think they are low.
Indeed, in my personal opinion, an attempt to make it an absolute
mandate would be counterproductive to compromise on a recommendation.
Taking a "mandate or nothing" position would likely result in nothing.
(I'm not saying that you are taking such a position).

--
Richard Maine | Good judgment comes from experience;
email: my first.last at org.domain | experience comes from bad judgment.
org: nasa, domain: gov | -- Mark Twain
.

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