Virtual machines (VMs) are a popular target for language implementers.
Conventional wisdom tells us that virtual stack architectures can be
implemented with an interpreter more efficiently, since the location
of operands is implicit in the stack pointer. In contrast, the
operands of register machine instructions must be specified
explicitly. In this paper, we present a working system for translating
stack-based Java virtual machine (JVM) code to a simple register
code. We describe the translation process, the complicated parts of
the JVM which make translation more difficult, and the optimisations
needed to eliminate copy instructions. Experimental results show that
a register format reduces the number of executed instructions by over
35\%, suggesting that virtual register machines are a viable
alternative to stack machines when interpreted on modern pipelined
architectures.
