Sinclair ZX80 / ZX81 / Z88 Forums

Hi all, Here is a new game for a 1Kb ZX81 called QFrogger. I had this idea to write a number of games in 1Kb using about a quarter of the screen. I'll be entering it into the next mini game competition. Keys are Q - T for up. A - G for down, O for right and P for right. Thanks to Chad Gray for beta ...

Having read Colins message, I thought I would add how I handle screen address calculation. It might be a byte or two longer but doesn't need the table and takes the same amount of time regardless of coordinates. As I don't use basic once my M/c starts, the start of the display never moves so don't n...

I was about to ask a question on why I could only load a program of about 898 bytes into a 1K zx81 but after a bit of checking, found that by using 'RAND USR VAL "xxxxx"', BASIC needs about 50 bytes more to handle it then just "RAND USR xxxxx". I can now load a maximum of 949 bytes. The first 9 byte...

An idea that would be good in an updated ROM is to rearrange the system variables so that the largest continuous block of memory, not used by the interrupt routines or those used when loading a program, is available. This will give somewhere else to put M/C on a 1K machine.

Hi all,

I've written a game for the ZX81 1K which I hope to enter into one of these 1k competitions that are doing the rounds.

Its about 95% done, with 100 bytes left to use up and so I am looking for anyone who would like to beta test it, add comments and find any bugs.

Anyone interested?

As far as I am aware, its not possible to get hires on zx81 with 16K without hardware modification.

Hi Bob, just had a look at your website and you have some seriously good looking games. I use eightyone 1.0a which probably the best emulator, http://www.chuntey.com/ . Have a look at Mastering Machine Code on your ZX81 by Toni Baker at http://www.worldofspectrum.org/infoseekid.cgi?id=2000236 . Its ...

Hi, this is my first post to this board so be gentle. I came across the ZX81 Art Competition 2007 recently and it got me thinking about using Mosaic generators to create pictures for the ZX81. Heres a couple I've done. Clive1_result.jpg Mona.Lisa.smile.by.da.Vinci_result.jpg If you want to try some ...