Search found 233 matches

by Diminished
Mon Apr 06, 2020 11:12 am
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

Hi, l would say we should go back to basics and create new versions from BillC's originals.... OK, Having dug through some magazine reviews of these games, the release timeline was as follows: Repton 3: December 1986. Reviewed in Micro User Dec '86, Computer Gamer Dec '86, and A&B Computing Jan '87...
by Diminished
Mon Apr 06, 2020 11:07 am
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

So, it seems there has been some confusion, most of which is probably my fault. The only version that we have found so far with the bug is the very first Repton 3 stand-alone full-price disc release (which we've been calling "v1"). This seems to be the version that's on Stairway to Hell (or at least...
by Diminished
Sun Apr 05, 2020 5:57 pm
Forum: off-topic
Topic: Electronics 101 help needed - transitors as a relay
Replies: 4
Views: 130

Re: Electronics 101 help needed - transitors as a relay

I think you want something like this: https://reviseomatic.org/help/e-MOSFET-BJT/Bipolar-Transistor-Switch.gif The base resistor is necessary to avoid blowing up the transistor. The diode is also necessary ... to avoid blowing up the transistor. In grossly oversimplified terms, NPN and PNP are oppos...
by Diminished
Sun Apr 05, 2020 11:55 am
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

Yeah, I realised yesterday that -- because I'm a dummy -- I'd been comparing a disc version (Bill Carr v1) to a tape version (bbcmicro.co.uk), which certainly explains some of the wilder differences I found. ("Why is this OSFILE stuff so starkly different? Ohhhh ...") Provided the level editor is in...
by Diminished
Sat Apr 04, 2020 3:09 pm
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

I had 4 disc copies of Repton 3, three with the gold "Superior Software DO NOT REMOVE" write protect stickers and one with plain black stickers. The three didn't have LDA#&FF on sector &15D, offset &AB, but the other one did, so seems like a fixed version was released. That sleeve also contains a c...
by Diminished
Sat Apr 04, 2020 1:08 pm
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

Hi, no problem, if we find something wrong then we need to post it here for testing as there are enough of us to fix just about any issue. Just one thing, did you try both D024's I posted or just the fix as if the original one I posted lastly was OK, then I can leave it as it is. thanks Mick. Hi Mi...
by Diminished
Sat Apr 04, 2020 12:19 pm
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

OK. Here's a test for whatever versions you lovely folks have. If you can complete Screens A and B then your version is bug-free. If you can't, it isn't. Because of the unpredictable way the fungus grows (i.e. sometimes it doesn't), it might be worth playing it twice, just to be sure. Load the game ...
by Diminished
Sat Apr 04, 2020 9:06 am
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

Could someone please playtest this version to see if it contains a fixed version or not. Originally, the game would have come from the tape, but on re-mastering a few years back, I may have used a disc version from later issues without realising the original fault. Hi Mick. Sorry to mess you around...
by Diminished
Sat Apr 04, 2020 7:53 am
Forum: introduce yourself
Topic: evening from york
Replies: 10
Views: 269

Re: evening from york

Hello!
philbo34 wrote:
Fri Apr 03, 2020 7:39 pm
as usual cant stand having anything that doesnt appear to work
This is the correct attitude!
by Diminished
Fri Apr 03, 2020 9:37 pm
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

It would be useful if there was a quick and simple way of identifying whether a copy has this bug fixed or otherwise. I have original floppy copies of Repton 3, ATWIFS, LOR and RTT, so would be interesting to see if they have the bug. (incidentally, I had also wondered if it had been fixed in house...
by Diminished
Fri Apr 03, 2020 7:27 pm
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

The plot thickens. It's been bothering me -- I just refused to believe this bug wasn't fixed at some point back in the day. Repton 3 was obviously very popular, else Superior wouldn't have seen profitability in releasing three expansion packs. Somebody had to have encountered this one on a normal pl...
by Diminished
Fri Apr 03, 2020 8:03 am
Forum: off-topic
Topic: Which retro calculator is best?
Replies: 19
Views: 501

Re: Which retro calculator is best?

You were lucky in the 90s - you had calculators. When I did my exams 'when I were a lad' we had to use 4-figure maths tables for sines, cosines, tangents and calculation using logarithms. :lol: I found a book of 7-figure tables in WH Smiths and thought I was in heaven. :wink: I think we had it luck...
by Diminished
Fri Apr 03, 2020 5:24 am
Forum: off-topic
Topic: Which retro calculator is best?
Replies: 19
Views: 501

Re: Which retro calculator is best?

I did my GCSEs in the early 90s (NEAB) and all I really remember needing was trig functions and square roots for quadratics and Pythagoras. Pretty sure we didn't need logs, exponentials or factorials by that point, or nPr / nCr. I know we were taught matrices at one point, but I think they were remo...
by Diminished
Thu Apr 02, 2020 2:16 pm
Forum: introduce yourself
Topic: Hello from Greater Manchester
Replies: 7
Views: 142

Re: Hello from Greater Manchester

Welcome!
by Diminished
Thu Apr 02, 2020 2:15 pm
Forum: introduce yourself
Topic: Hello from the Chew Valley
Replies: 7
Views: 177

Re: Hello from the Chew Valley

Welcome to the forum. That's a pretty nice pedigree you have there!
by Diminished
Wed Apr 01, 2020 1:01 pm
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

I'm glad. I think I'll pass on racing you, though. I think I beat screens A-D of Prelude as a child and then didn't get any further. Great game though, particularly with the editor. User-created content is king in gaming these days, so this was only 35 years ahead of its time. That's the second bug ...
by Diminished
Wed Apr 01, 2020 11:22 am
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

No gratitude needed -- I'm stuck indoors on my own and slowly going mad, so distractions are welcome. Plus it was a good excuse to brave the uncharted realms of another classic title. Patch. I made a simple level in the editor which I think exercises all of the game's features, and I also made eight...
by Diminished
Tue Mar 31, 2020 7:40 pm
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

The way I developed it was quite primitive since I didn't have a linker. A block of code is defined by a jump table of several JMPs into the actual routines themselves so I didn't have to keep changing addresses of those routines used in other assembler. In general the last JMP was the last routine...
by Diminished
Tue Mar 31, 2020 4:08 pm
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

Matthew, if you're still reading this ... what are the chances I can find a bit of spare RAM for a patch? Do you have any idea where? EDIT: This looks like where the patch is needed, starting at &2FF8. Ltimebomb_defused jsr i_disable_gameplay jsr L170c jsr L1919 lda v_current_level asl a tax lda $32...
by Diminished
Tue Mar 31, 2020 3:08 pm
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

The initial delay before the fungus seems right, I think that came at the request of Steve Botterill who found that if you had a screen with a lot of fungus to start with then it was on your case straight away. He wanted a fungus delay at the screen start so as not to make it too difficult. IIRC th...
by Diminished
Tue Mar 31, 2020 1:03 pm
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

(hi, Matthew!) meditating deeply on this, i think i recall reading that anecdotally there’s a delay at the start of the level before fungus grows at all… So it’s possibly that that’s misbehaving rather than the fungus growth routine itself. still need to test more. I think you may be spot on with t...
by Diminished
Tue Mar 31, 2020 10:56 am
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

I've made a little progress. I've located the fungus routine. It's at &27B1. fungus dec v_downcount_1_lo bne L_fungus_ret lda #$04 sta v_downcount_1_lo dec v_downcount_1_hi bpl L27c1 lda #$17 sta v_downcount_1_hi L27c1 ldx #$1b stx $62 L27c5 lda v_downcount_1_hi ldx $62 jsr L1ca6 cmp #$1a bne L282b ...
by Diminished
Tue Mar 31, 2020 8:36 am
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

Well, that's ... unfortunate.

Thanks for stopping by, Matthew.
by Diminished
Mon Mar 30, 2020 4:35 pm
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

Would it not be possible to save a machine state save (whatever you want to call it) once you've completed screens A to C? I think the point was to try different versions -- save states wouldn't help with that, as they contain the whole of RAM at the time of the save, so you'd effectively be loadin...
by Diminished
Mon Mar 30, 2020 3:17 pm
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

So I dumped the RAM in-game and tossed it into WFDIS. The code looks a little bit evil. I see a lot of indirection -- jump tables, pointer tables, and I'm guessing an orgy of self-modification. I let the game run for about a second and had the emulator print all the JSRs, so if anyone wants to follo...
by Diminished
Mon Mar 30, 2020 1:30 pm
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

OK, that's really interesting. It's not quite the end of the story, though, since that guy is playing on an emulator, and it might very well also be BeebEm; he doesn't specify whether the issue occurred on original hardware or not. I still think it's unlikely to be emulator-specific, although if you...
by Diminished
Mon Mar 30, 2020 10:03 am
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

Possible approach (thinking aloud): - find a level with fungus, or just design one in the editor - save state - wait for the fungus to spread, note where it spreads to - load state again, open debugger - find a byte in VRAM that is overwritten by the new piece of fungus, set a watchpoint - wait for ...
by Diminished
Mon Mar 30, 2020 9:40 am
Forum: software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 68
Views: 1699

Re: Repton 3: Emulator/RNG issue

Welcome to the forum. I bet this is a bug in the original game... Do we have a disassembly of this anywhere? I'm sure I've seen someone on here say they'd been through it. I did start disassembling Repton 1 at one point (it was fascinating to see the difference in programming style between Tim Tyler...
by Diminished
Sat Mar 28, 2020 9:23 pm
Forum: general
Topic: Photos of your Acorn setup, Back In The Day?
Replies: 19
Views: 466

Re: Photos of your Acorn setup, Back In The Day?

Pernod wrote:
Sat Mar 28, 2020 9:04 pm
This is me at Christmas 1982 with the new Beeb, connected to the big TV.
I love this one because almost exactly the same scene happened in our house when our machine arrived. Set up on the coffee table, with the tape recorder next to it.
by Diminished
Sat Mar 28, 2020 6:24 pm
Forum: general
Topic: Photos of your Acorn setup, Back In The Day?
Replies: 19
Views: 466

Re: Photos of your Acorn setup, Back In The Day?

Man, all you posh kids with disc drives. :x :lol: