JACKPOT 100

As seen on my recent YouTube live stream, JACKPOT 100 is a simple fruit machine style game, nothing spectacular it was more of a programming exercise.  Both versions,  ZX Spectrum and ZX81 have been programmed in BASIC and are available for download, REACH 100 to win the JACKPOT!!! 

The ZX81 build is the interesting half of this. A stock 1K machine is a brutal budget, and a fruit machine needs a surprising amount of state visible at once.

Did you have to cut anything from the Spectrum version to make it fit, or did the BASIC come out close enough on both?

We work on Game Boy cartridges rather than Sinclair hardware, and what always bites us is that the display eats the budget before the game logic gets a look in. We haven't found a way round that yet. Curious whether the ZX81 does the same to you.

Hi,  the ZX81 BASIC code is basically near enough the same as the ZX Spectrum version, with a few little tweaks here and there,  I'm also using a 16K ram pack so boasting the standard 1K.  I try to avoid constant screen printing, limit subroutines, and any unnecessary screen collision checks, keeping the main game loop as optimised as possible.  The programming process of this particular game is available on my YouTube channel as it was created during a 5 hour live programming stream, link available on the game page. 

A fruit machine is a better exercise than it sounds, because the whole thing lives or dies on the random source, and on 8 bit BASIC that is not a given.

Did you end up seeding it? The classic Spectrum gotcha is that without a RANDOMIZE the sequence is identical from a cold boot, so the first few spins repeat every single time the game is loaded. RANDOMIZE with no argument pulls from the frame counter, which is about as close to free entropy as that machine has.

Doing the ZX81 as well is the part I would have found hardest. Between those two the display handling is less a port than a rewrite.