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

> 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
>>
>>
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>
>
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