Pearls: 6502 Assembly Language Server

Pearls is a fast, robust, and fully-featured Language Server (LSP) and extension for developing 6502 Assembly in Visual Studio Code. It is specifically tailored for Merlin32/6502 syntax and designed to provide a modern, intelligent IDE experience for retro-programming.

Features

Intelligent Semantic Highlighting: Goes beyond basic regex. Pearls parses your entire workspace and highlights resolved local labels, global labels, directives, and operands with rich, context-aware colors.
Hover Hints & Documentation: Hover over any mnemonic (like LDA or ADC) or pseudo-directive (like DSK or ORG) to instantly see its syntax, addressing modes, and documentation.
Go to Definition: Instantly jump to the exact file and line where a label, variable, or macro was defined.
Find All References: See everywhere a specific label or memory address is used across your entire project.
Code Lenses: See inline reference counts for your subroutines and data blocks right above the code.
Workspace Navigation: Press Ctrl+T (or Cmd+T) to search for any symbol, equate, or macro anywhere in your workspace.
Automatic Diagnostics: Get instant squiggly lines for malformed syntax, unresolved references, and duplicate labels as you type.

Supported Syntax

Pearls is highly optimized for the Merlin32 macro assembler syntax, including:

Standard 6502 mnemonics
Merlin32 pseudo-directives (ORG, EQU, DSK, MAC, DO, IF, etc.)
Global and local labels (e.g., ]loop, :branch)
Hex ($FF), Decimal (255), and Binary (%11111111) literals

Getting Started

Install the extension.
Open any .s, .S, or .asm file.
The Pearls Language Server will automatically boot in the background and begin indexing your project.

Semantic Highlighting Note

To get the most out of Pearls' intelligent colorization, ensure you have Semantic Highlighting enabled in your VS Code settings:

{
  "editor.semanticHighlighting.enabled": true
}

(Note: Pearls includes custom color overrides so your code will look beautiful regardless of your currently active theme!)

Contributing

For instructions on building the extension from source, running the test suite, or contributing to the language server, please see DEVELOPMENT.md.

Pearls