ZX Spectrum Next Assembly Developer Guide
ZX Spectrum Next is the successor of the Sinclair Spectrum line from the 80-ies. With all the advanced features it truly brings Spectrum to the next millenium! On a personal note though, Next represents coming back home, to Speccy, the computer where I did my first steps into the world of programming. Steps that turned into career and a journey that still fascinates me as much as it did back then!
Built upon Z80 processor, Next inherits its rich CISC intruction set. For assembler developer, CISC architecture means a plethora of useful instructions that would typically need to be implemented manually, combining multiple instructions on RISC side. But on the downside, it's hard to remember them all and even then, instructions require variety of CPU cycles and take different amount of bytes in RAM. While Next comes bundled with great manual, it only really covers BASIC.
When I started learning Z80 assembly, I quickly desired for a booklet where all instructions would be listed with some basic information such as number of bytes, CPU cycles, effects on flags etc. This would allow me to quickly assess the difference between them and chose the optimal one for task at hand. There are various documents online providing this, but neither really scratched my itch. So I fell into frequent programmer trap of "do it myself" and set to write my own. After finding Z80 undocumented, it seemed like the perfect starting point. I updated it to be more relevant for Next developer and added many new chapters explaining different areas from the perspective of assembler developer: ULA, Layer 2, Tilemap, Sprites, Sound etc. These chapters represent my notes as I was learning those topics. The rest of the book consists of instructions lists and instructions descriptions. I did leave in existing chapter about Z80 too, I found it insightful read for Next developer too!
The book is written as introduction, however I made great effort to keep it relevant as reference as well. It's not intended as comprehensive manual though, it covers relevant areas and provides enough material to get things going. Further exploration into details and edge cases, if needed, is passed to the reader.
See introduction section in the PDF for information on the book, its history, origins, and more.
The book is available in two formats:
- Free to download PDF file or
- Printed coil bound book, if you prefer to have physical copy
Note: both books are the same apart from couple small differences:
- PDF shows sub-sections in main TOC, printed book not; typically only a small portion of page is visible on screen at once and TOC is clickable, so it makes sense to allow reaching specific areas. Printable book on the other hand provides much better overview, including sub-sections would only add noise.
- PDF doesn't include alphabetical instructions table; mainly because it's searchable so I felt it just adds noise
- Email addresses are obfuscated in PDF, printed book uses proper
[email protected]notation
You can build printable variant yourself from sources. In fact, it's enabled by default (mainly to avoid me uploading PDF for physical book using obfuscated emails). But please don't publish it in that form, it will make all emails much easier for bots to extract!
Editing
This is just as suggestion to help you if you're starting with LaTeX, not a prerequisite - feel free to use whichever editor and distribution you prefer!
I use VS Code with the following LaTeX plugins for editing:
For compiling LaTeX, I use https://miktex.org/
Styling guide
My main intention with this document was to have printed book, therefore PDF is styled primarily with that in mind. When editing content it's important to ensure information fits nicely. Mainly: specific topic should remain on the same even/odd page boundary as much as possible to allow user to see all relevant information with as little paging as possible. Of course larger topics will be split between multiple pages. It's fine to split individual parts from odd to even page, as both pages are visible when the book is open, but when the information is crossing from even to odd page, care should be taken. Most of the time, I opted to use small gaps so the following content is available in full on next page. Sometimes I also sacrificed order (for example instructions details section) to avoid too much gap.
To help with layout, I suggest using 2 page spread mode. If you're using LaTeX Workshop plugin, you can change preview to open in this mode with this setting:
"latex-workshop.view.pdf.spreadMode": 2
Sample code
Sample code from the book is also included in this repository. I use VS Code for programming Next as well. I only tested the programs on Windows so while all tools should be available on Linux and macOS, some configuration may need tweaking. You can find information on setup I use in the PDF.
Todo / Ideas
See GitHub issues or contact me!
Also one bigger thing: I'd prefer to have the book in smaller physical size, something between A5 and A4. It would get more pages, but would fit better in hand and on the shelf. Most of the content would hopefully flow nicely, however some will be problematic (instructions at a glance come to mind). Maybe Royal or Crown Quarto - though I don't think either is available as coil bound variant (and this type of book would benefit a lot from such binding). Also need to check if more pages will affect the price...
License
ZX Spectrum Next Developer Guide and companion source code are available under GNU license, please see the end of PDF document for full licence info!