Vertex

 ___      ___  _______   _______  ___________  _______  ___  ___  
│"  ╲    ╱"  │╱"     "│ ╱"      ╲("     _   ")╱"     "││"  ╲╱"  │ 
 ╲   ╲  ╱╱  ╱(: ______)│:        │)__╱  ╲╲__╱(: ______) ╲   ╲  ╱  
  ╲╲  ╲╱. .╱  ╲╱    │  │_____╱   )   ╲╲_ ╱    ╲╱    │    ╲╲  ╲╱   
   ╲.    ╱╱   ╱╱ ___)_  ╱╱      ╱    │.  │    ╱╱ ___)_   ╱╲.  ╲   
    ╲╲   ╱   (:      "││:  __   ╲    ╲:  │   (:      "│ ╱  ╲   ╲  
     ╲__╱     ╲_______)│__│  ╲___)    ╲__│    ╲_______)│___╱╲___│ 
                                                                  

A complete stack-based virtual machine implemented in Rust, featuring functions, control flow, and I/O operations.

Architecture

Stack-Based Design

Vertex uses two separate stacks:

• Value Stack: Temporary computation values
• Call Stack: Function call frames with local variables

Bytecode Format

Instructions are encoded as:

[OpCode: 1 byte][Operands: variable length]

Example:

PUSH 42       → [0][42,0,0,0,0,0,0,0]  (1 + 8 bytes)
STORE_VAR "x" → [6][1]['x']             (1 + 1 + 1 bytes)

Features

Core Operations

• Arithmetic: ADD, SUB, MUL, DIV
• Comparisons: GT, LT, GTE, LTE, EQ, NEQ
• Variables: STORE_VAR, LOAD_VAR, STORE_LOCAL, LOAD_LOCAL

Control Flow

• Unconditional jumps: JUMP <address>
• Conditional jumps: JUMP_IF_FALSE <address>
• Enables if/else and while loops

Functions

• Function calls: CALL <address>
• Returns: RETURN
• Local variable scope per call frame
• Full recursion support

I/O

• PRINT <string> — Print string literal
• PRINT_VAL — Pop and print value from stack
• PRINT_LN — Print newline

Debugging

• Bytecode disassembler
• Stack traces on errors
• Debug mode with step-by-step execution
• Instruction counter

Example Programs

Factorial (Iterative)

result = 1
n = 5
while n > 0:
    result = result * n
    n = n - 1
print result  // Output: 120

Fibonacci Sequence

a = 0
b = 1
while counter < 10:
    print a
    temp = a + b
    a = b
    b = temp
    counter = counter + 1
// Output: 0 1 1 2 3 5 8 13 21 34

Technical Details

Memory Model

• Global Memory: HashMap for global variables
• Call Frames: Stack of frames, each with local HashMap
• Value Stack: Vec for computation
• Bytecode: Vec<u8> with instruction pointer

Performance

• O(1) instruction fetch
• O(1) stack operations
• O(1) average variable lookup
• O(n) overall execution time

Future Enhancements

• Garbage collection
• JIT compilation
• More value types (strings, arrays)
• Standard library
• Text-based language compiler targeting Vertex bytecode
• Optimizer (constant folding, etc.)