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From Rodrigo Kumpera <kump...@gmail.com>
Subject Re: half-baked idea? j2me
Date Tue, 01 Nov 2005 13:45:06 GMT
On 11/1/05, Robin Garner <robin.garner@anu.edu.au> wrote:
> > On 11/1/05, Robin Garner <Robin.Garner@anu.edu.au> wrote:
> >> Rodrigo Kumpera wrote:
> >>
> >> >AFAIK IKVM, sablevm and jamvm all run on portable devices.
> >> >
> >> >Developing a j2me jvm is not as easier as it seens, first, the
> >> >footprint and execution performance must be really optimized, so
> >> >expect a LOT of assembly coding.
> >> >
> >> >
> >> Back to the language wars again :)  This does not necessarily follow.
> >> Try googling for the 'squawk' VM - they had a poster at OOPSLA last
> >> week.  This is a java-in-java virtual machine targetted at embedded
> >> devices.  The core VM runs in 80KB of memory.  Device drivers are all
> >> written in Java.
> >>
> >
> > Robin,
> >
> > With a java-in-java VM even if you don't write directly in assembly
> > you still need to generate machine code with java anyway, and that
> > will look a lot like asm (JikesRVM baseline JITer for example). With
> > C, for example, you can get away using just an interpreter.
>
> My mistake, obviously.  When you said "performance must be really
> optimized, so expect a LOT of assembly coding", I assumed you were saying
> that large chunks of the VM would need to be written in assembler in order
> to get adequate performance.
>
> So what _was_ the point you were making ?
>
> cheers
>
>

I was just trying to say that a decent j2me VM is not as simple as
David suggested. Not that C or Java would be more suited to implement
it. As a matter of fact, I think that java-in-java VMs can be as good
as C/C++ based JVMs or better.

But one thing is hard to deny, a simple JVM, like bootJVM, is a lot
easier to write in C than in java (not using an AOT compiler). And
that was my point, C/C++ sounds to be the easy path to start with.

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