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by dr beep
Wed Nov 08, 2023 6:52 pm
Forum: Sinclair Misc
Topic: The "Ask Dr Beep anything" thread
Replies: 17
Views: 14081

Re: The "Ask Dr Beep anything" thread

NOT YOUR TURN, mrtinb
by dr beep
Wed Nov 08, 2023 4:07 pm
Forum: Sinclair Misc
Topic: The "Ask Dr Beep anything" thread
Replies: 17
Views: 14081

Re: The "Ask Dr Beep anything" thread

What is your most favorite instruction/feature when coding on the Z80 in assembly? On the ZX81 that is the feature that code can be executed during line display, the call to upper memory. In hires I use this mainly to prevent display of a user defined character. In lowres it is used by the system w...
by dr beep
Tue Nov 07, 2023 8:09 pm
Forum: Sinclair Misc
Topic: The "Ask Dr Beep anything" thread
Replies: 17
Views: 14081

Re: The "Ask Dr Beep anything" thread

I played on a ZX81 in the '80s but never had one. I made a port of my ZX Spectrum game SHOGUN in 2011. It was a hires game and while searching the net I found a routine to code a 1K hires demo. This demo gave me the idea to start coding a full game in just 1K. The fact that you only have 1K (screen ...
by dr beep
Tue Nov 07, 2023 8:04 pm
Forum: Sinclair Misc
Topic: The "Ask Dr Beep anything" thread
Replies: 17
Views: 14081

Re: The "Ask Dr Beep anything" thread

How did you start coding on the ZX81?
by dr beep
Tue Nov 07, 2023 8:03 pm
Forum: Sinclair Misc
Topic: The "Ask Dr Beep anything" thread
Replies: 17
Views: 14081

The "Ask Dr Beep anything" thread

To give this forum some traffic I have set up this thread. If you have a question for me just ask here and I will give an answer. This can be anything about coding on the ZX81 but also a bit more personal. I will start with the first question and the answer and then it is up to you. Rules: no next q...
by dr beep
Tue Nov 07, 2023 7:45 pm
Forum: GAMES
Topic: New ZX81 Games
Replies: 363
Views: 682106

Re: New ZX81 Games

The rom could be found there: https://www.sinclairzxworld.com/viewtopic.php?p=31962#p31962 But I testet GOL-bugfree in EO, using the ZX81x2 rom. And it worked :o The problems seems to be my USB driver environment, I use to load the program. The USB driver updates some sysvars, to return information...
by dr beep
Tue Nov 07, 2023 6:21 pm
Forum: GAMES
Topic: New ZX81 Games
Replies: 363
Views: 682106

Re: New ZX81 Games

Siggi,

I have room enough to bypass all sysvar during loading so I will make a version with normal sysvar for you.

Mostly I need every byte but here I need a large screen so I have all room for some code I normally place over sysvar.
by dr beep
Tue Nov 07, 2023 2:05 pm
Forum: GAMES
Topic: New ZX81 Games
Replies: 363
Views: 682106

Re: New ZX81 Games

I see only 1 loop working properly (corners do not erase)
so somehow after the first loop the second is not run.
This is possible if LASTK is somehow effected.

It could be that LASTK is the sysvar used by the ROM.

Can I see the ROM somewhere?
by dr beep
Tue Nov 07, 2023 11:45 am
Forum: GAMES
Topic: New ZX81 Games
Replies: 363
Views: 682106

Re: New ZX81 Games

Well, I don't use CLS from the ROM.

Very weird that not even a cursor appears since that test is only reading LASTK.

So the game does create an inverse screen?

Make video of what happens. Then I can determine where it goes wrong.
by dr beep
Tue Nov 07, 2023 8:00 am
Forum: GAMES
Topic: New ZX81 Games
Replies: 363
Views: 682106

Re: New ZX81 Games

Cubimaze works as expedted and does not crash ... But GOL starts and creates a blanc inverted screen in 2 steps? First leaving corners, the clear corners? If so then game loads ok. And then pressing a key (latest version NEWLINE/SPACE) gives the cursor? And THEN setting a colony with Z gives a crash?