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Re: Trying to merge java.lang.Float, java.lang.Double with Classpath-- help wanted


Andrew Haley wrote:
Nathanael Nerode writes:
> >They are only GCJ-specific because they use CNI. There is nothing that > >is specific to any given VM implementation, ie a JNI implementation in > >classpath should work anywhere.
> > They depend on the bit encoding of doubles and floats. This is not > specified on the Java Virtual Machine specification;


Yes it is; the Java VM requires IEEE-754.

http://java.sun.com/docs/books/vmspec/2nd-edition/html/Concepts.doc.html#33377

Yep, and the underlying C native code [1] may not be offering IEEE-754, as the ISO C standard doesn't specify a floating format, AFAIK. So you *may* need some abstraction/conversison layer between the OS representation of floating points and Java's representation of floating points.


At least if you're interested in portability to non-IEEE754 machines ;)

That's why I like Classpath's design better, but then, I'm not a gcj developer yet, maybe next year ;)

cheers,
dalibor topic

[1] If you are using C, of course. Things may be different for other languages.


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