[Sablevm-user] Re: 64 bit alignment

[Etienne M. G. <eg...@j-...>]

xli wrote:
> Do you have any clue how the SUN team implements this?

Their source code license is too restrictive for me to look at.  In JITs
or in compiled code (e.g. HotSpot, Jalapeno), this is probably not a
problem.  But for interpreters (JDK interpreter, HotSpot interpreter)
this is a problem.  I expect them to do as I suggested, as interpreters,
by definition, do not rewrite bytecode, and maintaining longs/doubles
separately is pretty fastidious, unless I missed some implementation
trick.  One such trick would be to detect non-aligned longs/doubles in
the verification step, and reserve space for them explicitly, replacing
the stack operations by special ones.  But this is tricky in presence of
untyped stack instructions (e.g. dup2_x2).

> I tried to find other open source JVM, but failed.

try:

http://www.kaffe.org/
http://www.japhar.org/
http://www.intel.com/research/mrl/orp/
http://www.openjit.org/
http://latte.snu.ac.kr/
http://sources.redhat.com/java/


Etienne
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-- 
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Etienne M. Gagnon, M.Sc.                     e-mail: eg...@j-...
Author of SableCC:                 http://www.sable.mcgill.ca/sablecc/
and SableVM:                                   http://www.sablevm.org/
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