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Don't be shocked. This is a lot of text but I'm afraid without giving some detailed information I cannot really show what this is all about (and might get a lot of answers that don't really address my question). And this definitely not an assignment (as someone ridiculously claimed in his comment).
Prerequisites
Since this question can probably not be answered at all unless at least some prerequisites are set, here are the prerequisites:
- The Virtual Machine code shall be interpreted. It is not forbidden that there may be a JIT compiler, but the design should target an interpreter.
- The VM shall be register based, not stack based.
- The answer may neither assume that there is a fixed set of registers nor that there is an unlimited number of them, either one may be the case.
Further we need a better definition of "better". There are a couple of properties that must be considered:
- The storage space for the VM code on disk. Of course you could always scrap all optimizations here and just compress the code, but this has a negative effect on (2).
- Decoding speed. The best way to store the code is useless if it takes too long to transform that into something that can be directly executed.
- The storage space in memory. This code must be directly executable either with or without further decoding, but if there is further decoding involved, this encoding is done during execution and each time the instruction is executed (decoding done only once when loading the code counts to item 2).
- The execution speed of the code (taking common interpreter techniques into account).
- The VM complexity and how hard it is to write an interpreter for it.
- The amount of resources the VM needs for itself. (It is not a good design if the code the VM runs is 2 KB in size and executes faster than the wink of an eye, however it needs 150 MB to do this and its start up time is far a