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

by Ian Rogers (nabble) :: Rate this Message:

Hi Liangliang,

if you look in the boot image writer you can see variants of the VM
magic that don't return null (these are the actual versions compiled
into Jikes RVM), the purpose of the other magics is to capture the API
for javac compile time. When the compiler sees the unboxed classes it
doesn't treat them as objects with method calls but instead places the
unboxed value in a register and directly applies arithmetic, etc. to
it. The code for this is in files with magic in their name within the
compilers.

Regards,
Ian
--
Looking for Jikes RVM on 64bit Linux? Switch to MRP - http://mrp.codehaus.org/

2009/6/15 Liangliang Tong <lltong@...>:

> 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
>
>
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