Re: real.c implementation

[Andrew Haley <aph at redhat dot com>]

Robert Dewar writes:
 > > I agree.  gcj, if course, requires exact IEEE float conversion and
 > > relies on gcc to do it right,
 > 
 > Well what does this mean?

For me to describe this precidely would require me to quote the Java
Language Specification at considerable length, and there's no point in
me doing that here.

 > Are you talking about the IEEE requirements for float conversion

Yes.

 > Or are you talking about last bit exact conversion (they are not the same,
 > you need arbitrary precision for last bit exact conversion).

 > And what about the issue of biased vs unbiased rounding. The IEEE standard
 > has nothing to say about this (more accurately, it requires the choice to be
 > delayed till runtime so that it is done with the current dynamic rounding,
 > but that's too silly to take seriously).

Java requires round to nearest or even.

 > Just saying "exact" is not good enough here.
 
Good enough for what?  All I was saying is that

a.  Java has somewhat strict requirements for decimal-float conversion, and
b.  We need gcc to do The Right Thing.

Neither of these can reasonably be disputed.

Andrew.