How many games have actually been created in z-machine version 6 and 7? I take it v6 only four: the ones Infocom created (Zork Zero, Arthur, Journey and Shogun).
But what about v7? Have any games actually been published in that language, and what are Z7’s limits?
I’m sure it’s no longer a complete list, but ‘Z-code games in uncommon formats’ on IFWiki demonstrates that there has been at least one Z7 work.
(Which the web interpreter used by IFDB / iplayif.com chokes on, incidentally.)
Yeah. I tried Custard - the effects are really crazy!
Unfortunately, there is no way to play V6 and V7 on Parchment, so trying to make those games makes it inaccessible for most.
Z7 has the same graphics/screen model as ZV5/8; only the memory model is different. (Same
4N+S address format as Z6, but addresses can go up to 512k.) This turned out to be useless in practice. Z8 has the same practical limit and is easier to deal with.
The Z6 ports of Brian Howarth’s Mysterious Adventures are missing from that list.
Many interpreters handle z7 well, and it’s really not hard to do:
- Calculate a base string offset and a base routine offset when the game starts
- Whenever reading a string or routine address, add the offset
That’s it. Apart from this, you can just treat it as z8.
Ozmoo needed about 30 new lines of assembly code to deal with z7. In a high-level language it’s more like five lines of code.