Bytecode VM Skill

Overview

Expert skill for bytecode virtual machine design including instruction set design, dispatch mechanisms, and stack/register architectures.

Capabilities

• Design bytecode instruction sets
• Implement stack-based vs register-based VMs
• Implement efficient dispatch (switch, computed goto, threaded)
• Design compact bytecode encoding
• Implement bytecode verification
• Handle exception handling in bytecode
• Design inline caching for dynamic dispatch
• Implement bytecode serialization/deserialization

Target Processes

• bytecode-vm-implementation.js
• interpreter-implementation.js
• jit-compiler-development.js
• repl-development.js

Dependencies

VM implementation literature (Crafting Interpreters, Programming Language Pragmatics)

Usage Guidelines

1. Architecture Selection: Choose stack-based for simplicity, register-based for performance
2. Dispatch Mechanism: Use computed goto/threaded dispatch for hot loops
3. Encoding: Design compact bytecode encoding to improve cache locality
4. Verification: Implement bytecode verification for security and debugging
5. Inline Caching: Add inline caching for polymorphic call sites

Output Schema

{
  "type": "object",
  "properties": {
    "architecture": {
      "type": "string",
      "enum": ["stack-based", "register-based", "hybrid"]
    },
    "dispatch": {
      "type": "string",
      "enum": ["switch", "computed-goto", "direct-threaded", "indirect-threaded"]
    },
    "instructionCount": { "type": "integer" },
    "encoding": {
      "type": "string",
      "enum": ["fixed-width", "variable-length"]
    },
    "generatedFiles": {
      "type": "array",
      "items": { "type": "string" }
    }
  }
}