What is SkoolKit?

SkoolKit is a collection of utilities that can be used to disassemble a Spectrum game (or indeed any piece of Spectrum software written in machine code) into a format known as a skool file. Then, from this skool file, you can use SkoolKit to create a browsable disassembly in HTML format, or a re-assemblable disassembly in assembly language. So the skool file is - from start to finish as you develop it by organising and annotating the code - the common ‘source’ for both the reader-friendly HTML version of the disassembly, and the developer- and assembler-friendly version of the disassembly.

The latest stable release of SkoolKit can always be obtained from skoolkit.ca; the latest development version can be found on GitHub.


With SkoolKit you can:

  • use sna2ctl.py to generate a control file (an attempt to identify routines and data blocks by static analysis) from a snapshot (SNA, SZX or Z80) or raw memory file

  • enable sna2ctl.py to generate a much better control file that more reliably distinguishes code from data by using a code execution map produced by an emulator

  • use sna2skool.py along with this control file to produce a disassembly of a snapshot or raw memory file

  • add annotations to this disassembly (or the control file) as you discover the purpose of each routine and data block

  • use skool2html.py to convert a disassembly into a bunch of HTML files (with annotations in place, and the operands of CALL and JP instructions converted into hyperlinks)

  • use skool2asm.py to convert a disassembly into an assembler source file (also with annotations in place)

  • use skool2ctl.py to convert a disassembly back into a control file (with annotations retained)

  • use skool2bin.py to convert a disassembly into a raw memory file

  • use tap2sna.py to convert a TAP or TZX file into a ‘pristine’ Z80 snapshot

  • use snapinfo.py to analyse a snapshot or raw memory file and list the BASIC program it contains, show register values, produce a call graph, find tile graphic data, find text, or find sequences of arbitrary byte values

  • use tapinfo.py to analyse the blocks in a TAP or TZX file, and list the BASIC program it contains

  • use bin2tap.py to convert a snapshot or raw memory file into a TAP file

  • use bin2sna.py to convert a raw memory file into a Z80 snapshot

  • use snapmod.py to modify the register values or memory contents in a Z80 snapshot

  • use sna2img.py to convert graphic data in a disassembly, SCR file, snapshot or raw memory file into a PNG image

In an HTML disassembly produced by skool2html.py you can also:

  • use the image macros to build still and animated PNG images from graphic data

  • use the #AUDIO macro to build WAV files for sound effects and tunes

  • use the #R macro in annotations to create hyperlinks between routines and data blocks that refer to each other

  • use [Bug:*], [Fact:*] and [Poke:*] sections in a ref file to neatly render lists of bugs, trivia and POKEs on separate pages

For a demonstration of SkoolKit’s capabilities, take a look at the complete disassemblies of Skool Daze, Back to Skool, Contact Sam Cruise, Manic Miner, Jet Set Willy and Hungry Horace. The latest stable releases of the source skool files for these disassemblies can always be obtained from skoolkit.ca; the latest development versions can be found on GitHub.


SkoolKit is developed and maintained by Richard Dymond, and contains contributions from Philip M Anderson.


SkoolKit is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

See the file ‘COPYING’ (distributed with SkoolKit) for the full text of the licence.

48K ZX Spectrum ROM

A copy of the 48K ZX Spectrum ROM is included with SkoolKit (skoolkit/resources/48.rom). The copyright in this ROM is held by Amstrad, who have kindly given permission for it to be redistributed.