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44 lines
2.0 KiB
44 lines
2.0 KiB
7 years ago
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# uVM - Micro Virtual Machine
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uVM is simply an experiment ins developing a working virtual machine with it's own bytecode.
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## Requirements
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* CMake version 3.8 or higher
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* Clang and Clang++
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## Building
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1. `git clone` the repository
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2. `cmake .`
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3. `make`
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## Architecture
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uVM is a _stack machine_. That is, it gets all of it's arguments from the stack, and returns the result
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of the computation back to the stack when it's done.
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There are some exceptions to this. In particular the current version of uvm supports a single variable,
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called `0`, that can be written to using `xpop0` where x is the datatype of the thing getting taken off
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the stack.
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Additionally `0` can be placed on the top of the stack using `xpush0`.
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## uVM Instruction Set
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uVM possesses the standard issue instruction set you might expect in a simple VM:
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| Instruction | Opcode | Action |
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| ------------ | ------ | ------------------------------------------------------------------------------ |
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| ipush _X_ | 0 | Pushes _integer_ X onto the stack |
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| ipush0 | 1 | Pushes the _integer_ in `0` onto the stack |
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| ipop0 | 2 | Pops the top _integer_ of the stack off and into variable 0 |
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| icmp | 3 | Compares the top two items on the stack together and returns a boolean result |
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| iadd | 4 | Adds the top two _integer_ arguments of the stack together |
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| isub | 5 | Subtracts the top two _integer_ arguments of the stack from each other |
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| jmp _LABEL_ | 6 | Unconditional jump to _label_ |
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| jc _LABEL_ | 7 | Jump if the top of the stack is a 1 |
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As I learn more about VM development this instruction set will likely become much more robust.
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