STAR VIRTUAL MACHINE

A 16-bit virtual machine and assembly programming language designed for educational purposes.

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A Simple "Hello, World!"

.data
    string: .stringz "Hello, World!" # defines a string in memory
.instr
start:
        la $g, string # load string address into $g
        li $a, 0 # load 0 into $a
loop:   
        llb $a, $g # load $a with the byte at address $g
        beqa $a, $zero, end # if $a is 0, jump to end
        
        li $aux1, 7 # load 7 into $aux1
        move $aux2, $a # move $a to $aux2
        mcall # syscall

        inc $g # increments $g by 1
        ja loop # jump to loop
end:    nope # no operation (end of program)

The Star Virtual Machine assembly language is designed to be simple and educational, allowing users to learn the basics of assembly programming and low-level concepts.

The above program demonstrates how to print "Hello, World!" by loading a string from memory and using a machine call to output each character.

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Introduction

To get started with the Star Virtual Machine you can read the the introduction.

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Documentation

Syntax

To learn about the syntax of the Star you can read the following documentation:

• Instructions: Learn about the available instructions in the Star.
• Pseudo-Instructions: Learn about pseudo-instructions and how they simplify assembly programming.
• Registers: Understand the registers used in the Star and their purposes.
• Directives: Understand the directives used in Star.
• Processors: Explore the processors that enhance the assembly language capabilities.
• Machine Calls: Learn about system interaction and I/O operations.

Memory

To understand the memory model of the Star you can read the following documentation:

• Instruction Memory: Understand how instruction memory works and its role in the virtual machine.
• Data Memory: Learn about data memory and how it is used to store values.
• Position Memory: Learn about position memory and its importance for debugging and error reporting.

Compilation Stages

To learn about how the Star compilation processes you can read the following documentation:

• Scanner Stage: Understand how the scanner reads source code and converts it into tokens.
• Parser Stage: Learn how the parser analyzes tokens and constructs an abstract syntax tree (AST).
• Resolver Stage: Discover how the resolver processes the AST and resolves symbols.
• Generation Stage: Understand how the assembler generates machine code
• Execution Stage: Learn how the virtual machine executes the generated code.