Re: Clause 10, Expression Evaluation

[Nick Maclaren <nmm1@xxxxxxxxxxxxx>]

"William Clodius,,," <wclodius@xxxxxxxx> wrote:
> However while the default semantics of C as interpreted by gcc  
> complicate ensuring deterministic floating point behavior I suspect  
> it was doable in that time period. For their purposes the strict  
> legality of the code was less important than the reproducibility of  
> the interpretation of the code by one compiler on a limited set of  
> systems. The mapping of the Sisal expressions to the C code would  
> probably not be idiomatic, e.g, intermediate expressions would have  
> to be assigned to temporary variables, and some forms of floating  
> point optimization would have to be disabled. ...

Well, yes.  But, given that most of the supercomputers I have
had anything to do with have had slightly non-standard IEEE 754
support (in some cases, mandatorily), I suspect that the set of
systems was extremely limited.

The paper might provide some information on that.


Regards,
Nick Maclaren,
University of Cambridge Computing Service,
New Museums Site, Pembroke Street, Cambridge CB2 3QH, England.
Email:  nmm1@xxxxxxxxx
Tel.:  +44 1223 334761    Fax:  +44 1223 334679