[DGD] Current Status of VM efforts

[Felix A. Croes]

Carter Cheng <cartercheng at gmail.com> wrote:

> I am somewhat curious about the current status of the VM efforts wrt
> to the Hydra and dgd-osr projects. Is there currently a JIT planned
> for this?

I just merged my newvm branch, which updates DGD's virtual machine,
into the main repository.  The old VM was almost 20 years old, and
getting a bit long in the tooth.  Old code will still work, but newly
compiled LPC code will run on the new virtual machine.

The old virtual machine has a peculiarity that it shares with the
other LPmud servers: it has lvalues (left-hand values in an assignment)
as a runtime type.  The new VM does away with these, bringing it more
into line with present-day VM designs.  This should also simplify
compiling code from DGD's VM to a different architecture.

As to a JIT compiler for DGD, all I have is the notion that it should
compile from the internal VM code to a mainstream virtual machine
(Java, Mono, LLVM?) and possibly to C, so that it could be architecture-
independent.  The drawback would be multiple translation stages
(DGD VM code -> LLVM code -> host machine code).  I have no settled
plans for starting work on this, so you're certainly welcome to
give it a try, yourself.

Regards,
Felix Croes