uvm/README.md

uVM - Micro Virtual Machine

uVM is simply an experiment ins developing a working virtual machine with it's own bytecode.

Requirements

• CMake version 3.8 or higher
• Clang and Clang++

Building

1. git clone the repository
2. cmake .
3. make

Architecture

uVM is a stack machine. That is, it gets all of it's arguments from the stack, and returns the result of the computation back to the stack when it's done.

There are some exceptions to this. In particular the current version of uvm supports a single variable, called 0, that can be written to using xpop0 where x is the datatype of the thing getting taken off the stack.

Additionally 0 can be placed on the top of the stack using xpush0.

uVM Instruction Set

uVM possesses the standard issue instruction set you might expect in a simple VM:

Instruction	Opcode	Action
ipush X	0	Pushes integer X onto the stack
ipush0	1	Pushes the integer in 0 onto the stack
ipop0	2	Pops the top integer of the stack off and into variable 0
icmp	3	Compares the top two items on the stack together and returns a boolean result
iadd	4	Adds the top two integer arguments of the stack together
isub	5	Subtracts the top two integer arguments of the stack from each other
jmp LABEL	6	Unconditional jump to label
jc LABEL	7	Jump if the top of the stack is a 1

As I learn more about VM development this instruction set will likely become much more robust.