Elaborate Repton 1 Electron Cheat !

reminisce about bbc micro & electron games like chuckie egg, repton, elite & exileRelated forum: adventures


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Snuggsy187
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Elaborate Repton 1 Electron Cheat !

Post by Snuggsy187 » Sun Nov 10, 2019 8:08 pm

So, after the Repton 2 cheat, I thought I'd have a look at the original Repton. Obviously it's not as complex as Repton 2 , but I thought what the hell. Found 2 pages of free space at &2400-25FF to put the cheat code in ! Also not much usage of &0A00-&0CFF (although I used some for the loader).

Similar stuff to Repton 2, but I've incorporated some radio buttons onto the bottom right of the screen.

Press C to toggle the general Cheat mode - infinite lives, immune to rocks and reptiles, no time limit, instant map (without collecting the Map icon).

Press D to toggle "Destroy walls". Does what it says on the tin, boulders and everything. Be careful not to walk out of the playing area, it sometimes corrupts the map when you walk back on.

Press E to toggle "Push Bricks" (horizontally). Note, D and E can't be active at the same time !

Also tidied up the scrolling, so you don't get the Repton blurr effect !

Attached the ASM - not very annotated, but here it is.
Compile the ASM with:
beebasm -i Repton1-E-Cheat.ASM.txt -do Repton1-E-Cheat.ssd -boot LOAD

What next..... Repton 3.....? :!:
Attachments
Repton1-E-Cheat.ASM.txt
(119.17 KiB) Downloaded 6 times
Repton1-E-Cheat.ssd
(24.5 KiB) Downloaded 7 times
Repton1-E-Cheat.uef
(25.24 KiB) Downloaded 3 times
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0xC0DE
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Re: Elaborate Repton 1 Electron Cheat !

Post by 0xC0DE » Sun Nov 10, 2019 8:44 pm

This is excellent work! =D> =D> =D>

I love that you fixed the Repton "trail" while scrolling!
The cheats work well though I can't figure out what I can move around (option E).

It seems you also removed the 'protection' code in the loader that uses undocumented opcodes, correct?

Keep up the good work, I'm enjoying this and applaud all coding efforts on the Electron!
0xC0DE
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Re: Elaborate Repton 1 Electron Cheat !

Post by Snuggsy187 » Sun Nov 10, 2019 9:15 pm

Many thanks 0xC0DE :D

That trail has annoyed me for 30 odd years, it had to go !

Looking at some of my file dates, I ripped the initial disassembly back in 2015 (was it really THAT long ago ?!), then shelved it (!).
Had a quick look at the original loader disassembly, there's some vaguely annoying EOR encryption - can only think back then I just grabbed the title screen data, peeked how it was loading the main game part (it loaded to &0E00 and EOR'd everything with &FF), and ditched the rest of the code.

Much fun doing this one - surprised how quickly I found what I was looking for to incorporate all the cheats - that Tim Tyler was a proper programmer ! :D =D>

The "E" cheat can be used to push "free" bricks and safes left or right. If you get trapped and a wall has nothing the other side of it, you can push the brick !
Last edited by Snuggsy187 on Sun Nov 10, 2019 10:49 pm, edited 2 times in total.
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0xC0DE
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Re: Elaborate Repton 1 Electron Cheat !

Post by 0xC0DE » Sun Nov 10, 2019 9:21 pm

I wrote about it on Twitter not long ago:

The loader (REPTON0) of the Electron version is deliberately littered with undocumented NOPs it seems. It doesn't fool my debugger 😉 Execution starts at &2BDF after an initial sneaky BRKV redirection.


EHPSurcXUAcrpk_.png
0xC0DE
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Re: Elaborate Repton 1 Electron Cheat !

Post by Snuggsy187 » Sun Nov 10, 2019 9:31 pm

That just jogged my memory - I cheated and used the Blue Ribbon Re-Release version, a lot that that stuff is missing from that version - just the EOR encryption !
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Elk2019
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Re: Elaborate Repton 1 Electron Cheat !

Post by Elk2019 » Mon Nov 11, 2019 1:17 pm

Nicely done Snuggsy187. The Repton series of games has baffled, puzzled and frustrated many players over the years. Good to see these handy trainers to help us all and improving the scrolling was brilliant. Keep up the good work!

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Re: Elaborate Repton 1 Electron Cheat !

Post by Snuggsy187 » Mon Nov 11, 2019 7:28 pm

Thanks Elk2019 :D

Had me baffled back in the day too - those 3 pesky reptiles on level K !

Pleased with the new scrolling - tried to do something similar with Repton 2, but couldn't get it right (slightly different print routine), I might revisit it at some point......... :)
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davidb
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Re: Elaborate Repton 1 Electron Cheat !

Post by davidb » Tue Nov 12, 2019 11:08 am

Fascinating! :D

It's interesting to see that the map has its own tile on the map screen! And the display doesn't wrap around when you leave one edge, though you can see that your progress is being recorded on the map.

I love this kind of cheat that lets you treat the game like a sandbox. :)

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Re: Elaborate Repton 1 Electron Cheat !

Post by Snuggsy187 » Tue Nov 12, 2019 8:02 pm

Thanks davidb, of course - sandbox, like it, didn't really think of it in those terms !

Now, onto Repton 3......perhaps...... Matthew Atkinson, different programmer, definitely a different programming style !
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Re: Elaborate Repton 1 Electron Cheat !

Post by Pernod » Tue Nov 12, 2019 8:17 pm

Snuggsy187 wrote:
Tue Nov 12, 2019 8:02 pm
Now, onto Repton 3......perhaps...... Matthew Atkinson, different programmer, definitely a different programming style !
I've known him since before Repton 3. He's in the Facebook group if you have any questions.
- Nigel

BBC Model B: ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, BeebZIF, etc.

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Snuggsy187
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Re: Elaborate Repton 1 Electron Cheat !

Post by Snuggsy187 » Wed Nov 13, 2019 7:47 pm

Many thanks for that Pernod :D I'll certainly bear it in mind !

Just found the 'dead' flag already (for infinite lives / immortality), so it's all going well at the moment !! :D
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