Sinclair ZX80 / ZX81 / Z88 Forums

A few months ago, I returned to doing a little ZX81 assembly programming after almost 25 years gone. In learning about the new tools and new emulators, I found no single "Getting Started" document, so I decided to create one. The paper is called "Assembly Language on the ZX81: An Updated Getting Sta...

Back in 1980, Popular Science ran a short article on this new ZX81 from the UK. I found it interesting but left it at that. Then, in Oct. 1980, my senior year in High School, Popular Science ran a full two page add for the ZX81, in either kit form or built. Having money from a summer job, I sent off...

Andy,

Thanks for the code. I've tested it myself with TASM and EightyOne and it worked just fine.

Tim Swenson

Bruno, If you know peoples names that were in the User Groups, you might have some luck tracking them down. Granted most of the Timex/Sinclair user groups in the US morphed from ZX81 users, to T/S 2068 users and QL users. Paul Holmgren, who traded as 1/2 of Mechanical Affinity, is still around on th...

I've done some tests and am a little bit closer. PLOT / UNPLOT For plot, I loaded BC with the X & Y values and it works. For unplot, I loaded BC with the X & Y values, then put $9E in $4030, and this works. But, the next call to plot, fails (I did not touch $4030 in between). I also found that putti...

After many years away, I've decided to get back to doing some Z80 assembly programming on the ZX81. I've updated the process a bit by using the TASM cross assembler and the EightyOne emulator. I still have my copies of Toni Bakers Book "Mastering Machine Code ..." and the ZX81 Rom book by Dr. Logan....