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Re: libjava configure question


Bryce McKinlay writes:
 > Andrew Haley wrote:
 > 
 > >Tom Tromey writes:
 > > > >>>>> "Andrew" == Andrew Haley <aph@redhat.com> writes:
 > > > 
 > > > Andrew> One other thing: I don't think we can do this in
 > > > Andrew> general and meet even the more relaxed requirements of
 > > > Andrew> java.lang.Math, because the x86 has a restricted range
 > > > Andrew> of allowable arguments to its trig functions.
 > > > 
 > > > I thought the Math restrictions were designed to explicitly allow use
 > > > of the FPU on x86.
 > >
 > >Yes, but not without some wrapper code.  The crucial issue here is
 > >full range reduction, and the floating-point instructions don't do
 > >that by themselves.
 > 
 > I'm sure the math library functions do, though - we'd still likely
 > get a performance improvement from using those directly, even
 > without inlining of FP instructions - since they'll be optimized
 > for each architecture.

Yes, that's probably true.  We'd have to make sure that calls to
java::lang::Math::sin() etc. were replaced by sin() and we'd also have
either to remove our own definitions of the functions or make them
weak.

All quite possible, but perhaps not top of the list.

Andrew.


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