New ZX81 game in BASIC

Anything Sinclair ZX Basic related; history, development, tips - differences between BASIC on the ZX80 and ZX81
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Buka
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New ZX81 game in BASIC

Post by Buka » Sat Jun 01, 2013 2:03 pm

Hello everyone!

Apologies for the clumsy English - is Google translator. :oops:

Never in my life did not concern the present Sinclair ZX81, but I recently did for him one old game.

Her descriptions and rules were published in 1990 in the Soviet journal http://en.wikipedia.org/wiki/Tekhnika_Molodezhi

Twenty-three years ago, many people have programmed it on many different computers.
I myself in 13 years (1993) started to write it for the Spectrum ... And then abandoned.

So I recently finished writing for the ZX81. In Basic. Rules (even if sometimes funny) tried to follow according to the journal article.

I know that the UDG to ZX81 is not so easy to do, but possible. Do not understand the intricacies of becoming I just sent them to the ROM for 7680 (1E00h). So the picture will be normal only in the emulator, with permission to write to the ROM.

The game became a little whole in the 16K. A bit assembler would help, but the last time I used it on the Spectrum in 1995.

So it's 100% pure BASIC!

P.S. Now do not clean basic. Changed attachment to the new version. :arrow:

PPS: Small mistake in line 239. :(
Corrected. If you and I will continue to fix that - not before the autumn.

upd 9.03.14 - Remove two small bugs.
Attachments
list.GIF
LLIST
(109.8 KiB) Downloaded 468 times
monstrland.p
game
(15.79 KiB) Downloaded 102 times
TM.zip
article describing the game (in Russian)
(1.62 MiB) Downloaded 109 times
Last edited by Buka on Sun Mar 09, 2014 3:39 pm, edited 8 times in total.
"The Earth is just too small and fragile a basket for the human race to keep all its eggs in." ― Robert Anson Heinlein
Elektronika MK61, Psion series 5mx have now. Many years ago had Spectrum 48, 128k/TRDOS and Amiga A600 ...

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Buka
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Re: New ZX81 game in BASIC

Post by Buka » Tue Jun 04, 2013 11:51 am

I'm sorry to have missed a little mistake.

Corrected file: see above.
Last edited by Buka on Thu Jun 06, 2013 10:37 am, edited 1 time in total.
"The Earth is just too small and fragile a basket for the human race to keep all its eggs in." ― Robert Anson Heinlein
Elektronika MK61, Psion series 5mx have now. Many years ago had Spectrum 48, 128k/TRDOS and Amiga A600 ...

sirmorris
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Re: New ZX81 game in BASIC

Post by sirmorris » Tue Jun 04, 2013 12:07 pm

Hi and welcome to the forum!

That's a lot of work you've done - you must be very dedicated :D

I will play this when I get the zx81 out again.

Thanks for sharing!

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Buka
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Re: New ZX81 game in BASIC

Post by Buka » Tue Jun 04, 2013 12:43 pm

Thank you.

On a real ZX81 will be ugly - UDG not work.
No hardware revision pointer to a character set can not be moved to RAM. Big mistake engineers who made this computer.

After all, it could have been foreseen in advance, and there are simple solutions. For example, in ftp://ftp.worldofspectrum.org/pub/sincl ... SUMThe.pdf page 55, for example refinement UDG.

I can make a version without the UDG, if needed.
"The Earth is just too small and fragile a basket for the human race to keep all its eggs in." ― Robert Anson Heinlein
Elektronika MK61, Psion series 5mx have now. Many years ago had Spectrum 48, 128k/TRDOS and Amiga A600 ...

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PokeMon
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Re: New ZX81 game in BASIC

Post by PokeMon » Tue Jun 04, 2013 9:05 pm

Cool !

sirmorris
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Re: New ZX81 game in BASIC

Post by sirmorris » Tue Jun 04, 2013 9:25 pm

Thanks for the link to the UDG circuit - I've been looking for this document for ages!

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XavSnap
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Re: New ZX81 game in BASIC

Post by XavSnap » Tue Jun 04, 2013 9:28 pm

Thanks Buka !
The UDG can't work on the $1E00 ROM address (IR register), because of the direct wirrings beatween the ULA and the ROM.
We had to put a memory RAM, placed on the ROM plug (using Dx' data bus on the wirring diagram).
Have fun.
DKTRONICS UDG Card:
http://translate.google.fr/translate?hl ... fr%2Fdk%2F

VTR card:
http://zx81.ordi5.free.fr/vtr/

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Buka
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Re: New ZX81 game in BASIC

Post by Buka » Tue Jun 04, 2013 10:31 pm

XavSnap wrote:Thanks Buka !
The UDG can't work on the $1E00 ROM address (IR register)
I know that. :roll:

it seems so easy - LD A, addr; LD I, A ...
But addr is possible only from the ROM to take - getting garbage on the screen.

This game was written under an emulator, so ... If the real CHR board can send 512 bytes of the character set to the correct address and set the IR - tell me where?

Oops, as he wrote - there were references to hardware. ;)
"The Earth is just too small and fragile a basket for the human race to keep all its eggs in." ― Robert Anson Heinlein
Elektronika MK61, Psion series 5mx have now. Many years ago had Spectrum 48, 128k/TRDOS and Amiga A600 ...

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Paul
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Re: New ZX81 game in BASIC

Post by Paul » Wed Jun 05, 2013 8:12 am

Sorry for beeing so unkind to correct you.
For UDG there is no need to change the data lines.
Only the lower address lines need to be A0'..A8' in order to get the ULA Adress lines instead of those from the Z80.
Kind regards
Paul
In theory, there is no difference between theory and practice. But, in practice, there is.

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Buka
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Re: New ZX81 game in BASIC

Post by Buka » Wed Jun 05, 2013 10:20 am

Test changes IR register.

On a real ZX81 100% should move in the limit h0-h2000.

In the limit of h2000-h4000 need to check with the real memory in this area...
Attachments
udg.p
(1.38 KiB) Downloaded 108 times
"The Earth is just too small and fragile a basket for the human race to keep all its eggs in." ― Robert Anson Heinlein
Elektronika MK61, Psion series 5mx have now. Many years ago had Spectrum 48, 128k/TRDOS and Amiga A600 ...

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