Introduction

Strontium is a bytecode machine with typed registers and multimethods for statically and dynamically typed programming languages.

It is built primarily to support Mag as the underlying, executive portion of the language engine. Any Mag source code first runs through the parser, is then compiled to Strontium bytecode and finally interpreted by this virtual machine.

Instruction Set Architecture

A lightweight RISC-like instruction set architecture is used to keep the number of instructions small and easily maintainable, while more complex tasks are achieved using combinations of multiple bytecode instructions.

Registers

The following registers are pre-allocated when the machine starts:

Register	Type	Content	Description
ip	UInt64	0	The index of the byte to be read next from the bytecode buffer in the bc register.
bc	Array<UInt8>	[]	The bytecode of the running program.
r1..r8	Empty		General purpose registers

Use the LOAD instruction to load values from bytecode into general purpose registers at runtime.

Instruction Set

The following instructions may then used in program bytecode to operate on the registers:

Opcode	Name	Description
0	HALT	Stop all execution instantly.
1	LOAD	Load a Value from program bytecode into a register.
2	MOVE	Move a value from one register to another. The source register will be cleared after the operation.
3	COPY	Copy a value from one register to another. The source will be left untouched.
4	CALCULATE	Perform a calculation (ADD, SUBTRACT, MULTIPLY, DIVIDE) on two registers and write the result to a third.
5	COMPARE	Perform a comparison (EQ, NEQ, LT, LTE, GT, GTE) on two registers and write the result to a third.
6	BITWISE	Perform a bitwise operation on one (NOT) or two (AND, OR, XOR, LSH, RSH) registers and write the result into another.
7	JUMP	Set the program counter to a value from a location, using one of the methods (absolute, forward, backward)
8	JUMPC	Same as the previous instruction, but with an additional register address argument. Will only perform the jump if the given register contains a Value::Bool(true).
9	INTERRUPT	Emit an event that needs immediate attention (READ, PRINT)
10	CALL	Unimplemented method call instruction
11	RETURN	Unimplemented method return instruction

This README will soon be updated with further documentation.

Project Status

This is still very much in the alpha phase, so the semantics and API surface of this library will change dynamically over time. Do not rely on this in any production-critical way and expect earth-shattering change.

Let's talk if you're interested on working on this project!

Tests

Coming soon

License

Licensed under the MIT license.