Re: Ada and Java. different behaviour. casting long to int problem.

[Keith Thompson <kst@cts.com>]

Hyman Rosen <hymie@prolifics.com> writes:
[...]
> Nope. Here's the quote from the report
> <http://www.esrin.esa.it/htdocs/tidc/Press/Press96/ariane5rep.html>:
> 
> 	The internal SRI software exception was caused during
> 	execution of a data conversion from 64-bit floating point to
> 	16-bit signed integer value. The floating point number which
> 	was converted had a value greater than what could be
> 	represented by a 16-bit signed integer. This resulted in an
> 	Operand Error. The data conversion instructions (in Ada code)
> 	were not protected from causing an Operand Error, although
> 	other conversions of comparable variables in the same place in
> 	the code were protected.

I've always found this wording a bit odd.  The way Operand Error is
capitalized implies that it's a technical term, but course there's no
predefined Ada exception by that name.  Presumably they're referring
to Constraint_Error (or possibly Numeric_Error if they were using an
Ada 83 compiler).  Perhaps "Operand Error" is the name of a
hardware-level error condition?

Also, what does "protected from causing an Operand Error" mean?  I
*think* it refers to surrounding the operation with a local exception
handler, but it's not at all clear from the report (at least to me).

Obviously the report wasn't written for an Ada-aware audience (not
that it necessarily should have been).

-- 
Keith Thompson (The_Other_Keith) kst@cts.com  <http://www.ghoti.net/~kst>
San Diego Supercomputer Center  <http://www.sdsc.edu>                 <*>
One of the great tragedies of ancient history is that Helen of Troy
lived before the invention of the champagne bottle.