README progress

README.md

@@ -1,2 +1,31 @@
 # vim-syntax-asm_ca65
-Vim syntax highlighting for the ca65 assembler
+Vim syntax highlighting for the `ca65` assembler.
+
+## Purpose
+
+This codebase provides `asm_ca65.vim`, a Vim syntax-highlighting module for the
+`ca65` assembler.
+
+`ca65` is a full-featured assembler for the 6502 family of microprocessors,
+which powered such historic platforms as the KIM I, Apple II, Commodore 64, and
+Nintendo Entertainment System. It is a part of the popular `cc65` suite of
+development tools for the 6502, which also includes a C compiler, linker, object
+dumper, etc. `ca65` is designed both for direct use by assembly programmers and
+as the compilation target of the `cc65` C compiler. `ca65` is especially used by
+"homebrew" communities for the NES, SNES, etc.
+
+The stock Vim runtime distribution includes syntax modules for several dialects
+of assembly, as well as a "generic" module (which is really for the GNU
+Assembler), none of which works particularly well with 6502 assembly
+conventions, and especially not with `ca65`'s many added features in particular.
+
+## Features
+
+### Examples (screenshots)
+
+## Limitations
+
+## Installation
+
+## Usage
+