VM instruction implementation without huge switch()?

How would one go about making a virtual machine without using a huge and clumsy switch( opcode ) statement?

The architecture I'm implementing (DCPU-16) has about 35-40 different instructions.

You're writing in assembly, you don't have to be limited to the constraints of C.

http://www.complang.tuwien.ac.at/forth/threaded-code.html