Interpreters

This is a solid deep dive into bytecode VMs and simple JITs for anyone implementing a scripting language or runtime in C/C++. It walks through the dispatch loop strategies (switch, computed goto, direct threading) with real code showing why computed goto beats switch for branch prediction, covers stack vs register VM architectures, and includes practical patterns like NaN boxing and inline caching. The simple JIT section with mmap is a good entry point before you jump into LLVM. Honestly, this is the guide I wish I had when I first tried to understand why Lua switched to a register VM or how LuaJIT gets so fast. It assumes you're comfortable with C pointers and low-level systems programming.

skills.sh installs: 609
GitHub stars: 279
last updated: Aug 21, 2026

View on GitHub

Install

$ npx -y skills add mohitmishra786/low-level-dev-skills --skill interpreters --agent claude-code

Installs into .claude/skills of the current project.

Files

Interpreters and Bytecode VMs

Purpose

Guide agents through implementing efficient bytecode interpreters and simple JITs in C/C++: dispatch strategies, VM architecture choices, and performance patterns.

Triggers

"How do I implement a fast bytecode dispatch loop?"
"What is the difference between switch dispatch and computed goto?"
"How do I implement a register-based vs stack-based VM?"
"How do I add basic JIT compilation to my interpreter?"
"Why is my interpreter slow?"

Workflow

1. VM architecture choice

Style	Description	Examples
Stack-based	Operands on a value stack; compact bytecode	JVM, CPython, WebAssembly
Register-based	Operands in virtual registers; fewer instructions	Lua 5+, Dalvik
Direct threading	Each "instruction" is a function call	Some Forth implementations
Continuation-passing	Interpreter functions return continuations	Academic