Well, whatever our theories and thoughts, the fact is that there ARE three different ZX81 ROM chips. And each one has a slightly different section of code for the PAUSE command.
Unless the authors of the code go public on why, we can only speculate.
Mark
ZX81 ROMs 3 types?
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1024MAK
- Posts: 5527
- Joined: Mon Sep 26, 2011 10:56 am
- Location: Looking forward to summer in Somerset, UK...
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Re: ZX81 ROMs 3 types. Confirmed!
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Spring approaching...
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp
Standby alert There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Spring approaching...
Re: ZX81 ROMs 3 types. Confirmed!
This will be confirmed centuries from now!!
https://www.youtube.com/watch?v=NxZ7XAYkVo4
(sorry I'm very tipsy at the moment)
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Re: ZX81 ROMs 3 types?
KEITH LIES IN WAITLardo Boffin wrote: ↑Wed Jan 20, 2021 7:22 pm Maybe there are more ULA types than we thought?
Says Lardo running away.
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Re: ZX81 ROMs 3 types. Confirmed!
I did not know about the third ROM, thanks for the information
Last edited by David G on Thu Jan 21, 2021 9:41 am, edited 1 time in total.
Re: ZX81 ROMs 3 types. Confirmed!
Good information. I've been working on machine code which runs on either of the different ROMs. This inspired me to update my test program
runs in 1k. These are some typical ROM routines a machine language program might call (FAST, SLOW, PRINT-FP, etc). It will crash if we call any of these higher address ROM routines using the wrong address
runs in 1k. These are some typical ROM routines a machine language program might call (FAST, SLOW, PRINT-FP, etc). It will crash if we call any of these higher address ROM routines using the wrong address
- Attachments
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- ROMQUERY.p
- (857 Bytes) Downloaded 310 times
Re: ZX81 ROMs 3 types. Confirmed!
Glad we could help in some small way.
Nice little routine which is now in my toolkit folder.
Nice little routine which is now in my toolkit folder.
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Re: ZX81 ROMs 3 types. Confirmed!
Deleted for being rude to Lardo Baggins! 
Last edited by Moggy on Fri Jan 22, 2021 4:30 pm, edited 1 time in total.
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Lardo Boffin
- Posts: 2256
- Joined: Sat Nov 26, 2016 2:42 am
Re: ZX81 ROMs 3 types. Confirmed!
Nice little ROM type detection kit!
Last edited by Lardo Boffin on Fri Jan 22, 2021 3:04 pm, edited 1 time in total.
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
TS 1000 iss 3, ZXPand AY and +, ZX8-CCB, ZX-KDLX & ChromaSCART
Tatung 81 + Wespi
TS 1500 & 2000
Spectrum 16k (iss 1 s/n 862)
Spectrum 48ks plus a DIVMMC future and SPECTRA
-
1024MAK
- Posts: 5527
- Joined: Mon Sep 26, 2011 10:56 am
- Location: Looking forward to summer in Somerset, UK...
- Contact:
Re: ZX81 ROMs 3 types?
Oi! No squabbling at the back!
Mark
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Spring approaching...
ZX81 Chip Pin-outs
ZX81 Video Transistor Amp
Standby alert There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Spring approaching...
Re: ZX81 ROMs 3 types?
Please sir it was Lardo he started it he called me fatty. (true as it happens bah)
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