This is a simple stack-based virtual machine. Based on: http://blog.felixangell.com/virtual-machine-in-c/.
Instruction set:
- PSH imm: pushes immediate value onto the stack
- ADD: pops 2 elements off the stack and pushes on the sum
- POP: pops top element off the stack and prints it
- SET $t imm: $t = imm
- HLT: halts execution