Hotspot on PPC

Gary Benson gbenson at
Fri Jun 1 07:57:04 PDT 2007

Bob Vandette wrote:
> When we did the original IA64 port of Hotspot, we decided to use
> a "C" interpreter in order to get the port done quicker.  On
> architectures with many CPU registers, the "C" interpreter is
> actually just as fast or even faster than the generated assembly
> version.  We use the GCC computed goto in order to avoid the typical
> dispatching overhead of switch statements.  This interpreter is in
> hotspot/src/share/vm/interpreter/cInterpretMethod.hpp.  The problem
> is that the only architecture that uses the cInterpreter is IA64 and
> as far as I know, this code isn't open sourced.  You'd need to see
> the glue logic that exists in the CPU directory to use this
> interpreter.

That's interesting.  I found an environment variable that seems to
switch it on, CC_INTERP, but it's still trying to suck in machine-
dependent stuff.  Am I missing something, or is it simply that the
build system is not set up to build without the JITs?

Also, does this mean you have a working IA64 JDK internally?  Does
it exclusively use the C interpreter or was a JIT written later?
If it's possible to run OpenJDK with a C interpreter then of course
I'd love to know :)

> I don't know if you are aware of a Java 5 version of PowerPC that
> is on our Java SE Embedded site.  It is a hotspot implementation
> of Java SE 5.0 for Linux platforms.  It uses the Hotspot client
> JIT compiler and is only 32 bit but it has passed the fully JCK
> certification.

Interesting.  Are there any plans to open source it?


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