Sinclair ZX80 / ZX81 / Z88 Forums

The ZX81 uses a mix of software and limited hardware to create a video picture. The Jupiter Ace video system is based on hardware, it will continue to produce a video image even if the processor is stopped (HALTed) or busy (unlike the Zeddy). Hence 2K bytes of the 3K bytes of RAM in a Jupiter Ace i...

Better still, solder 4 resistors to the right places on the CPU, program an EPROM with the ZX80's ROM code, fit a reset switch across the reset capacitor and have the real thing on a ZX81. :D Yes, I am aware of that (haven't tried it yet, though) but a 100% software emulator (IF such a thing is pos...

I was looking at the superb dr beep's Sp-2-ZX80 emulator for the Spectrum and I just had a silly idea:
Could it somehow be ported to the Zeddy? Would this be possible?


It would be an out-of-this-world experience to see an emulator running on Zeddy!

dr beep wrote: ↑Fri May 26, 2023 6:59 pm You missed the SP-2-ZX81 too, wasn't it?

Yes!!! You remember it!
...but after all I enjoyed it very much, it's a real gem!

dr beep wrote: ↑Fri May 26, 2023 6:59 pm Did you miss my book too?

Aaaah, missed it as well!!!
Well, I must be sort of a missing person!

Wow, it's been some time since I last visited the forum and I had missed THAT??? :oops: I have no words to thank you, dr.beep! You are my hero!!! 8-) 8-) 8-) I look forward to seeing a bug-free, complete version with manual and .0 file converter, that would be astonishing! God bless you, you REALLY ...

I noticed a similar question from you on the Videopac-forum. I coded a Videopac-emulator in 2000 for the ZX Spectrum. https://spectrumcomputing.co.uk/entry/15647/ZX-Spectrum/Videopac_Emulator Yes, of course I already know it and I have it! Of course it doesn't look as nice as the original without t...

dr beep wrote: ↑Tue Mar 09, 2021 7:05 pm I just read the article, it is a copy of my emulator from 1997. I am honoured.

WOW!!!

Gameplay will ressemble pickaxe pete, but will be different. Ladders are now fixed and boulders will not bounce, only roll. I have to do some alterations to make it fit 1K.. Planned release date: 40th birthday A fav Videopac classic, plus dr beep's magic 1k coding skills on the Zeddy, will surely h...

bobs wrote: ↑Sun Feb 14, 2021 5:03 pm I can take zero credit for the game’s design and graphics, but 100% for bringing it quickly and accurately to the humble Zeddy.

Cheers, Bob!
We're always glad to see another one of your brilliant works on the Zeddy! Really nice, thank you!!!

I have decided NOT to make a version with the altered ZX81 ROM. The mainreason is that most optimizations in the ROM are found in speeding up routines. My emulator must emulate all routines and the gain would be marginal. To get speed in my emulator most used routines are translated to work in rewr...