Re: The disturbing myth of Eiffel portability

[mbk@caffeine.engr.utk.edu (Matt Kennel)]

Robert Dewar (dewar@merv.cs.nyu.edu) wrote:
: The idea that it is wrong to test for exact equality is quite incorrect,
: there are many algorithms where it is perfectly legitimate to test for
: exact equality if you know you are dealing with IEEE arithmetic.

: This *huge* performance hit occurs on fewer and fewer machines, nearly all
: machines now support IEEE arithmetic, and the decision to require this
: semantis in Java represents a final nail in the coffin for weird (and often
: badly designed) non-IEEE arithmetic systems. 

I think requiring "IEEE arithmetic" is acceptable if this means
"arithmetic on a well-defined finite subset of rationals" in a particular
bit representation. 

On the other hand, I think it is too strenuous and ill-advised for a language
to insist upon 100% full exact IEEE exception handling, as this
is far less often compatible with high performance and portability. 

--
Matthew B. Kennel/mbk@caffeine.engr.utk.edu/I do not speak for ORNL, DOE or UT
Oak Ridge National Laboratory/University of Tennessee, Knoxville, TN USA/