I want to build a Virtual Machine, are there any good references?
- by Michael Stum
I'm looking to build a Virtual Machine as a platform independent way to run some game code (essentially scripting).
The Virtual Machines that I'm aware of in games are rather old: Infocom's Z-Machine, LucasArts' SCUMM, id Software's Quake 3. As a .net Developer, I'm familiar with the CLR and looked into the CIL Instructions to get an overview of what you actually implement on a VM Level (vs. the language level). I've also dabbled a bit in 6502 Assembler during the last year.
The thing is, now that I want¹ to implement one, I need to dig a bit deeper. I know that there are stack based and register based VMs, but I don't really know which one is better at what and if there are more or hybrid approaches. I need to deal with memory management, decide which low level types are part of the VM and need to understand why stuff like ldstr works the way it does.
My only reference book (apart from the Z-Machine stuff) is the CLI Annotated Standard, but I wonder if there is a better, more general/fundamental lecture for VMs? Basically something like the Dragon Book, but for VMs? I'm aware of Donald Knuth's Art of Computer Programming which uses a register-based VM, but I'm not sure how applicable that series still is, especially since it's still unfinished?
Clarification: The goal is to build a specialized VM. For example, Infocom's Z-Machine contains OpCodes for setting the Background Color or playing a sound. So I need to figure out how much goes into the VM as OpCodes vs. the compiler that takes a script (language TBD) and generates the bytecode from it, but for that I need to understand what I'm really doing.
¹ I know, modern technology would allow me to just interpret a high level scripting language on the fly. But where is the fun in that? :) It's also a bit hard to google because Virtual Machines is nowadays often associated with VMWare-type OS Virtualization...
