[virtmach] parrot VM?

Reuben Thomas virtmach@iecc.com
Sat, 13 Jul 2002 00:26:45 +0100 (BST)

> 	But aren't there some portability issues with a register VM?
> 	Wouldn't you want to map the VM registers to real registers
> 	(since you want performance in the first place)? That
> 	might make it difficult to have a register VM that runs fast
>         on both, say, x86 and MIPS.

All this means is that you have to do register allocation. There are
tricks that allow you to do most of the work at VM compile time, and leave
little enough that a JIT compiler can still produce reasonable code fairly
fast. See my PhD thesis on Mite (www.mupsych.org/~rrt/research/).

> 	I'd say that a stack-based VM seems a good option if
> 	you want a portable VM and a simple compiler and code size
> 	is an issue.

I'd agree.

[Apologies to anyone who feels my replies on this subject are turning into
a series of ads for Mite; I'm only repeating myself for the benefit of
those who haven't read the whole thread!]

http://www.mupsych.org/~rrt/ | free, a.  already paid for (Peyton Jones)