An impressive way to crash the Speccy?

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R-Tape
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An impressive way to crash the Speccy?

Post by R-Tape » Sun Jul 22, 2018 7:05 pm

Does anyone have any suggestions for a short machine code routine that crashes the Speccy in a visually and/or audibly impressive way, and returns it to a NEW state?

(and if yes, can I rip it off in my next game? :mrgreen: )
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Re: An impressive way to crash the Speccy?

Post by MatGubbins » Sun Jul 22, 2018 7:44 pm

Bunging a paper clip on the expansion port usually works a treat!
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Re: An impressive way to crash the Speccy?

Post by R-Tape » Sun Jul 22, 2018 8:07 pm

MatGubbins wrote:
Sun Jul 22, 2018 7:44 pm
Bunging a paper clip on the expansion port usually works a treat!
Heh. Another Speccy to add to eBay's 'not tested but working' pile.

The best I can managed so far is a lazy border effect LDing down from the top of memory.

Image

It might have to do, argh, in which case I should have kept it to myself :shock:
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Re: An impressive way to crash the Speccy?

Post by Ast A. Moore » Sun Jul 22, 2018 8:32 pm

R-Tape wrote:
Sun Jul 22, 2018 7:05 pm
Does anyone have any suggestions for a short machine code routine that crashes the Speccy in a visually and/or audibly impressive way, and returns it to a NEW state?

(and if yes, can I rip it off in my next game? :mrgreen: )
Darn it. If I know you collected artsy Speccy crashes, I would have save a few for you. Just a few days ago I was making a fix for a game (don’t even remember which one), and it crashed just the way you want it: a few seconds of loading/saving sounds with the usual border animation followed by some random patterns on the screen and a reset.
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Re: An impressive way to crash the Speccy?

Post by 1024MAK » Mon Jul 23, 2018 5:50 am

The first year that I got my hands on a Speccy, when I had got my head around the normal BASIC commands and functions, I started playing with POKE and USR. I tried many combinations in the search for useful or interesting effects. But I did not keep much in the way of notes. And what I did keep, were typed up on said ZX Spectrum and printed on thermal paper. Paper that has not aged well...

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Re: An impressive way to crash the Speccy?

Post by dfzx » Mon Jul 23, 2018 7:37 am

1024MAK wrote:
Mon Jul 23, 2018 5:50 am
The first year that I got my hands on a Speccy, when I had got my head around the normal BASIC commands and functions, I started playing with POKE and USR. I tried many combinations in the search for useful or interesting effects.
I used to do the same thing. I still have "RANDOMISE USR 2272" committed to memory after all these years. But it doesn't end in a reset so it's not what the OP wants. :|
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Re: An impressive way to crash the Speccy?

Post by djnzx48 » Mon Jul 23, 2018 8:12 am

You might get some interesting effects by messing around with the I and R registers, for example setting I to point to contended memory.

I think Tomahawk also has some screen corruption effects for when you crash.
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Re: An impressive way to crash the Speccy?

Post by PROSM » Mon Jul 23, 2018 8:33 am

djnzx48 wrote:
Mon Jul 23, 2018 8:12 am
You might get some interesting effects by messing around with the I and R registers, for example setting I to point to contended memory.
The problem is that altering the I register would only crash the 128K machines IIRC, whereas the 16K/48K models continue to work (albeit with the screen snow still).

Changing R would probably only cause real Spectrums to crash, I don't know of any emulator that simulates DRAM leakage. ;)
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Re: An impressive way to crash the Speccy?

Post by Ast A. Moore » Mon Jul 23, 2018 9:20 am

PROSM wrote:
Mon Jul 23, 2018 8:33 am
The problem is that altering the I register would only crash the 128K machines IIRC, whereas the 16K/48K models continue to work (albeit with the screen snow still).
I did extensive testing some time ago to verify this hypothesis (I documented in on WoS), and I was unable to crash the 128K Speccy no matter how hard I tried. So there’s little substance to this notion.

That is not to say you can’t crash any Spectrum “the regular” way by messing with the interrupt vector register. Quite the opposite. :P
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Re: An impressive way to crash the Speccy?

Post by spider » Thu Aug 29, 2019 9:41 pm

Maybe:

Code: Select all

ORG 26000
XOR (HL)
LD DE,16384
LD BC,6912
LDIR
CALL 1335
JP 26000
Change the JP 26000 to JP 0 to reset obviously! I left it at self as it then generates some slightly different patterns, just break/space a few times:

Image

I did try a few other variations on this such as DI and/or doing something like LD A,R as well as playing with the Call address a bit, without a great deal of other effects really. I thought about more detailed border effects but it seemed a bit o.t.t.

:lol: :oops: :D
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