Don't optimize by hand (Was Re: Lack of fabsf on Solaris(patch included))

Fri Jan 26 09:06:00 GMT 2001

Kazuyuki Shudo writes:
 > Andrew Haley wrote:
 > 
 > > > And we probably don't really implement strict fp
 > > > semantics anyway
 > >
 > > The last time that I ran any tests we were 100% strict fp perfect.
Actually, this was a mistake. Sorry.
 > > That's better than the other Java implementation I tried!
 > 
 > Here is a test program.
 > If the Java runtime is compliant with the strictfp specification,
 > you will see the following:
 > 
 > % java StrictfpTest
 > shuJIT for Sun Classic VM/x86 by Kazuyuki Shudo
 > 1.112808544714844E-308 (0x0008008000000000)
 > * 1.0000000000000002 (0x3ff0000000000001)
 > default : 1.112808544714844E-308 (0x8008000000000)
 > strictfp: 1.1128085447148447E-308 (0x8008000000001)
 > 
 > 2.225073858507201E-308 (0x000fffffffffffff)
 > / 0.9999999999999999 (0x3fefffffffffffff)
 > default : 2.2250738585072014E-308 (0x10000000000000)
 > strictfp: 2.225073858507201E-308 (0xfffffffffffff)
Not necessarily: non-strict FP can be exactly the same as strict FP at
the implementor's discretion. In this case the question is, are the
values GCJ returns incorrect? If so, we have a bug in GCJ or in the
FPU itself.
I know I should do this calculation by hand to make sure, but...
Andrew.