Re: [STDS-754] Halfway cases for binary-to-decimal conversion in IEEE 754-1985

[Mike Cowlishaw <MFC@xxxxxxxxxx>]

> No, this matters, because e.g. the language standards may remain
> linked to IEEE 754-1985. For instance, this is the case of the
> ISO C99 standard (with its annex F), which has not been revised
> yet. If IEEE 754-2008 has stricter requirements than the 1985
> version, a conforming C99 implementation will not magically
> become non-conforming just because IEEE 754-2008 has obsoleted
> the 1985 version.

As I understand it: if a part of standard (A) is dependent on standard (B) 
then if standard (B) is no longer a standard for any reason (due to being 
revoked or superseded, for example) then that part of standard (A) is also 
no longer standard.

This has always been the case, and is one reason why standards minimize 
their dependence on other standards as much as makes sense.  It is also 
one reason why the committee revising IEEE 754 took so long, and debated 
at great length, any additions and changes.

In the case of language standards linked to the IEEE 754-1985 standard: 
indeed they do not magically inherit the 754-2008 standard.  Equally, any 
sections that previously depended on the IEEE 754-1985 standard are now 
'meaningless' as there is no such standard anymore.  I note that the C# 
and CLI standards from ECMA have already started the process of updating 
their standards to refer to IEEE 754-2008, and imagine other language 
standards will do the same in due course.

Hope that helps -- Mike







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