vanten-s.com/content/posts/os/2024-08-11.md

+++ title = 'Os Devlog: Lisp Compiler' date = 2024-09-08T12:00:00+02:00 categories = ["os"] tags = ["lowlevel", "lisp", "compiler"] summary = "LISP :3" draft = true +++

Introduction

In my previous article I wrote about my os. In this article I will explore the compiler I have made for the system.

Goals for the compiler

Goals are important for getting stuff done. With this compiler I want to:

• Implement a simple LISP language
• Compile to a format that my OS supports
• Functions
• Variables
• Loops
• If statements
• First-class functions

AST

For the program

(+ 1 (+
   a b ))

The AST looks like this:

   /  \
  +  /  \
    1  /  \
     /  \ NIL
    +  /  \
      a  /  \
        b   NIL

Compilation

My lisp-implementation is heavily stack-based, and only uses registers when using instructions that need them.

For example, a + function could compiler to this:

pop eax
pop ebx
add eax, ebx
push eax