The Incomplete Spectrum ROM Assembly


This is a text file generated programmatically from the original Sinclair ZX Spectrum ROM. It can be used as a source file by Zilog Z80 cross-assemblers to generate a binary image of the Spectrum ROM for use in emulators.

Originally all comments were added automatically. These are gradually being converted to human comments to form a simple online reference that may assist you in any alterations you make to the Spectrum ROM.

Online ZX Spectrum Assembly File

The adventure continues! Secret Passageway discovered in ZX Spectrum at address $121C.

This is featured in the new "Gosh Wonderful" ROM
new feature

Classic BASIC

The ZX range of computers run Minimal BASIC as their operating system.

Begin a tour of Classic BASIC programs by clicking
this link

White Knight

Odds and Ends

A temporary posting area for items of interest to the Sinclair Community.
Patents, FAQ, Scans, Z80 Source, SOFT ROM and TS2068 files.

Loose Ends


As the assembly files are quite large, download all the Z80 source code for offline use.

ZX ROMs Assembly Files Collection Download

The file contains zx82.txt, zx81.txt, zx80.txt, if1_1.txt, if1_2.txt and ace.txt.

As an example, zx82.txt assembles to zx82.obj which is 16384 bytes in length and may be used in your emulator
in place of the standard 16K ROM that came with it.

e.g. tasm -80 -b zx82.txt

If you are eager to see the benefits, make the one-line change that cures the CHR$ 9 error and test it. Don't stop there. You are in control now.


The Complete ZX81 ROM Assembly File

A complete assembly listing of the ROM of the Sinclair ZX81 / Timex TS-1000.

Online ZX81 ROM

Note. that this is the "Improved" ZX81 ROM. You can read a list of the Differences at Stephen Agate's Emulator Homepage.

Note. an even earlier ROM has come to light. There are, as yet, no Bootleg copies of the ROM but this is the keyboard it would have used.

There is also my customized ZX81 ROM variant which uses space-saving techniques to make way for Newton's square root calculation, improved decimal number input and consistent output to the screen and printer of floating point numbers.

The Shoulders of Giants ZX81 ROM Assembly.

Download the 8K ROM from here sg81.rom

The Complete ZX80 ROM Assembly File

A complete assembly listing of the legendary Integer Basic Sinclair ZX80 ROM.

Perhaps the most influential computer program ever written.

Online ZX80 ROM

or right-click this text file to save and compile your own version of the ZX80 ROM for use in emulators.

The Jupiter Cantab Ace ROM Assembly File

A rudimentry assembly listing of the FORTH-based Jupiter Cantab Ace ROM.
By the author of the ZX Spectrum BASIC ROM.

Online Jupiter Ace ROM

or right-click this text file to save and compile your own version of the Jupiter Ace ROM for use in emulators.

The ZX Interface 1 ROM Assembly Files

Two assembly listings of the Shadow ROM that gave Spectrum Users access to real printers, fast storage devices and a Local Area Network.

Online Interface 1 ROM - version 1

Online Interface 1 ROM - version 2 - after serial number 87315

or click this link to download plain source code for use in emulators.

The Gosh Wonderful BASIC ROM Assembly File

An adaptation of the standard assembly listing of the Basic Sinclair ZX Spectrum ROM.
This is a minor rework of the ROM which corrects most of the imperfections discovered during the Beta test phase. The remaining space is used to provide Renumber, Block Delete and Stream Lister commands.

Online Gosh Wonderful ROM Assembly File Listing

Try the Gosh Wonderful ROM online with the ZZ-Spectrum Java emulator. new feature

Get the ROM for your emulator here

Sinclair ZX Resource Centre

More ROMS and disassemblies at Paul Farrow's amazing site

including a wide range of Sinclair ZX Interface 2 ROM Cartridges

New! SPECTRA Interface adds state-of-the-30-year-old-art features to your ZX Spectrum!

John Harris

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