« Return to Thread: [rvm-research] How are the unboxed classes implemented?

Re: [rvm-research] How are the unboxed classes implemented?

by Steve Blackburn :: Rate this Message:

Hi Liangliang,

I'll just add a couple more comments.

The big picture is that in Jikes RVM we wanted new types that behaved
just like Java's primitive types (int, byte, etc). Of course we
can't (and don't want to) change the Java language so we use unboxing
and compiler intrinsics to achieve new types that are very similar to
primitive types in terms of performance.

If you're interested in the underlying ideas and design, the following
paper may be helpful to you. Some of it is historical, some of it is
speculative (things we hope to do, such as more general forms of
unboxing):

http://cs.anu.edu.au/~Steve.Blackburn/pubs/abstracts.html#vmmagic-vee-2009

Cheers,

--Steve

On 15/06/2009, at 7:03 PM, Liangliang Tong wrote:

> Hi all,
>
> Space.java, the class that defines and manages spaces, is constructed
> like the following:
>
> if (vmRequest.type == VMRequest.REQUEST_DISCONTIGUOUS) {
> this.contiguous = false;
> this.descriptor = SpaceDescriptor.createDescriptor();
> this.start = Address.zero();
> this.extent = Extent.zero();
> this.lastDiscontiguousRegion = Address.zero();
> VM.memory.setHeapRange(index, HEAP_START, HEAP_END);
> return;
> }
>
> As I know, Address and Extent classes have not been implemented, their
> methods return nothing but null.
> In this case, how can a space be created correctly? which really
> confuse
> me a lot.
> It will be highly appreciated if you can solve my puzzle.
> Thanks.
>
> --
> Regards,
> Liangliang Tong
>
>
> ------------------------------------------------------------------------------
> Crystal Reports - New Free Runtime and 30 Day Trial
> Check out the new simplified licensing option that enables unlimited
> royalty-free distribution of the report engine for externally facing
> server and web deployment.
> http://p.sf.net/sfu/businessobjects
> _______________________________________________
> Jikesrvm-researchers mailing list
> Jikesrvm-researchers@...
> https://lists.sourceforge.net/lists/listinfo/jikesrvm-researchers

------------------------------------------------------------------------------
Crystal Reports - New Free Runtime and 30 Day Trial
Check out the new simplified licensing option that enables unlimited
royalty-free distribution of the report engine for externally facing
server and web deployment.
http://p.sf.net/sfu/businessobjects
_______________________________________________
Jikesrvm-researchers mailing list
Jikesrvm-researchers@...
https://lists.sourceforge.net/lists/listinfo/jikesrvm-researchers

« Return to Thread: [rvm-research] How are the unboxed classes implemented?