Search found 62 matches

by swensont
Thu Jan 20, 2011 2:53 am
Forum: Development
Topic: ZX81 Rom Routines
Replies: 6
Views: 5625

Re: ZX81 Rom Routines

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...
by swensont
Wed Jan 19, 2011 5:02 am
Forum: Development
Topic: ZX81 Rom Routines
Replies: 6
Views: 5625

ZX81 Rom Routines

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....