Search found 122 matches

by Diminished
Sun Feb 17, 2019 9:15 am
Forum: general
Topic: Ideas please for better beep when Second Processor is present
Replies: 28
Views: 550

Re: Ideas please for better beep when Second Processor is present

Am I right in thinking that the pitch of the first tone is undefined, due to an uninitialised sound chip? Limits what you can do musically if so.
by Diminished
Fri Feb 08, 2019 11:58 am
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 986

Re: Lunar Jetman protection

Lunar Jetman has identical code at &6100, checking whether &240 isn't &47 &619C then decrypts &900 and executes it. Ah, that's why I failed to trap it -- it isn't decrypted until it's about to be executed. I should have bothered to read the code I posted myself. [-X Kevin outwitted me again. Thanks...
by Diminished
Fri Feb 08, 2019 3:23 am
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 986

Re: Lunar Jetman protection

BTW Which emulator did you use run and obtain the obfuscated code? I could do with trying this out for myself! I used b-em because it a) works well on Linux; b) is written in plain C and uses a lot of global variables, making it usefully hackable without much effort; and crucially c) is known to lo...
by Diminished
Thu Feb 07, 2019 8:49 am
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 986

Re: Lunar Jetman protection

I'm not great at this, but I modified b-em's JMP instruction to scan memory for Kevin's signature *FX 200, and came up with three sightings. Do these decoded blocks look right? &E00 BLOCK 0E00: A2 0E LDX #0E 0E02: 8E 00 FE STX FE00 0E05: A9 3A LDA #3A 0E07: 8D 01 FE STA FE01 0E0A: E8 INX 0E0B: 8E 00...
by Diminished
Wed Feb 06, 2019 2:03 pm
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 986

Re: Lunar Jetman protection

Having read the Nightshade thread years ago I have sometimes wondered how close you could get to something like this on modern systems. I imagine the lack of standardised hardware, and the operating system and executable format getting in the way probably means "not very". I do remember that some so...
by Diminished
Wed Feb 06, 2019 12:47 pm
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 986

Re: Lunar Jetman protection

Ah look, this is the code I was alluding to (in JETMAN3 from Colin's disk image): 0C91 TSX 0C92 CPX #&FE 0C94 BCS &0CA3 0C96 LDA &0102,X 0C99 EOR &FE48 0C9C ORA #&01 0C9E STA &FE68 0CA1 BNE &CAD 0CA3 LDA &02,X ; <-- looks like it should've been LDA &0002,X instead 0CA5 EOR &FE49 0CA8 ORA #&01 0CAA ...
by Diminished
Sat Nov 17, 2018 6:26 pm
Forum: hardware
Topic: Electron Data Recorder ?
Replies: 16
Views: 394

Re: Electron Data Recorder ?

Old Centronics printer cables, or (fully wired) PC serial cables (such as you'd use to connect to an external modem) ?
by Diminished
Thu Nov 15, 2018 4:24 am
Forum: general
Topic: How much of this is just rose-tinted specs?
Replies: 21
Views: 736

Re: How much of this is just rose-tinted specs?

Some of it has always been time pressure, surely? I don't think adults are necessarily any less capable of figuring out technology, but just don't have the time or the inclination. I forget who it was that said that sufficiently advanced technology is indistinguishable from magic, but that's how it ...
by Diminished
Sun Nov 11, 2018 6:52 pm
Forum: software: classic games
Topic: Unused Citadel bits
Replies: 71
Views: 7041

Re: Unused Citadel bits

I always thought the barrel was intended for jumping onto the roof of the Witch's House. Trampolines may have been added later on (tile ID &3a for the trampos but &18 for the barrel); so I suspect this was the originally intended solution and the trampolines were added to the game later.
by Diminished
Sun Nov 11, 2018 5:18 pm
Forum: software: classic games
Topic: Unused Citadel bits
Replies: 71
Views: 7041

Re: Unused Citadel bits

The second item certainly looks like a gold bar. :) In the early version of Citadel, once you took a cyan block to Stonehenge and walked under the arch, your energy increased and the cyan block turned into this gold one. Not sure what you was suppose to do with it after that. Aha. Nice find. I had ...
by Diminished
Mon Nov 05, 2018 4:21 am
Forum: software: classic games
Topic: Citadel Disassembly / Reassembly v0.1
Replies: 12
Views: 1479

Re: Citadel Disassembly / Reassembly v0.1

Cool. I'll integrate this when I get round to doing another release. I need to track down that relocation bug too, and I've improved some of the naming in my local copy. I botched the README slightly last time as well (rushed the release a bit) but it didn't seem worth repackaging the whole thing ju...
by Diminished
Sat Nov 03, 2018 3:42 pm
Forum: programming
Topic: The Dreaded goto
Replies: 4
Views: 355

Re: The Dreaded goto

I've sometimes resorted to "do { } while (0);" to avoid a goto (in which a break statement will jump you to the end of the block).

It's messy if you want to jump out of multiple blocks, though. The goto is probably clearer.
by Diminished
Sat Nov 03, 2018 1:09 pm
Forum: software: classic games
Topic: Unused Citadel bits
Replies: 71
Views: 7041

Re: Unused Citadel bits

Thank you for correcting my errors. Hope you don't mind me muscling in on your thread. Nope, not a problem. Information is free, and more eyeballs are welcome. I don't claim any right to the game. But there are certain insights that you'll only get from the asm. (Equally, there are likely to be som...
by Diminished
Fri Nov 02, 2018 2:45 pm
Forum: software: classic games
Topic: Unused Citadel bits
Replies: 71
Views: 7041

Re: Unused Citadel bits

Nope. I figured he'd chime in if he was interested in doing so.

No need to go stalking the guy.
by Diminished
Thu Nov 01, 2018 3:18 pm
Forum: software: classic games
Topic: Unused Citadel bits
Replies: 71
Views: 7041

Re: Unused Citadel bits

Bits 0,1,2,3 - Seems to selects which frames are displayed during animation sequences. Bits 4,5,6,7 - Speed of tile flipping in animations. 0 fastest, 16 slowest. Yeah, I mentioned this. Bits 0-3 choose an "A-type" animation subroutine for the tile from this pair of tables: ; note that these are al...
by Diminished
Tue Oct 30, 2018 1:33 pm
Forum: software: classic games
Topic: Unused Citadel bits
Replies: 71
Views: 7041

Re: Unused Citadel bits

Nice. That explains why it looked like gibberish. I'm wondering if originally this was supposed to be something to do with the crystals being presented at the Sanctuary. Whether they were supposed to sit in some sort of receptacle, and then MJ decided it wouldn't work for whatever reason. Or perhaps...
by Diminished
Mon Oct 29, 2018 9:55 pm
Forum: software: classic games
Topic: Unused Citadel bits
Replies: 71
Views: 7041

Re: Unused Citadel bits

Good work.

Maybe [1] bit 4 really isn't used then. Good news if true. Eliminate the table, reclaim the RAM. I'll check it definitively in a emulator when I can be bothered.
by Diminished
Mon Oct 29, 2018 5:04 pm
Forum: software: classic games
Topic: Citadel Disassembly / Reassembly v0.1
Replies: 12
Views: 1479

Re: Citadel Disassembly / Reassembly v0.1

I'd say it's unlikely at this time.
by Diminished
Mon Oct 29, 2018 4:57 pm
Forum: software: classic games
Topic: Unused Citadel bits
Replies: 71
Views: 7041

Re: Unused Citadel bits

Cool. I'm struggling mentally a bit at the moment, but I had a look at those unknown tile[1] and tile[2] bytes in the asm, and updated my local copy of the reassembly accordingly. NOTES - t_tslots_unk2[], where tile[1] bit 4 ends up, only ever seems to be written and not read. Having seen the rest o...
by Diminished
Sun Oct 28, 2018 5:30 pm
Forum: software: classic games
Topic: Unused Citadel bits
Replies: 71
Views: 7041

Re: Unused Citadel bits

I'm confused where the actual tile data is store. I see the tile list starts at &0955 and the first byte is the length which is then walked to the next such as &0990 .... &0996 .... &09a2. Some are only 6 bytes long, so the actual tile pixel data must be elsewhere but I cannot find where? The tiles...
by Diminished
Sat Oct 27, 2018 5:44 pm
Forum: software: classic games
Topic: Citadel Disassembly / Reassembly v0.1
Replies: 12
Views: 1479

Re: Citadel Disassembly / Reassembly v0.1

The torch thing isn't a bad idea! I'm wondering where you might be able to find any extra RAM to expand the game. Not much is available, unless you cheat and use sideways RAM, which honestly might be the way to go. Finding a way to compress the room names might be a place to start. You might save a ...
by Diminished
Thu Oct 25, 2018 3:56 am
Forum: software: classic games
Topic: Citadel Disassembly / Reassembly v0.1
Replies: 12
Views: 1479

Re: Citadel Disassembly / Reassembly v0.1

Anyone get the impression Diminished likes the game Citadel? :D Well, the number of people willing and able to undertake disassembly of old BBC games has to be pretty small at this point, and it's only going to get smaller. I still don't understand how parts of the game work, but publishing what I ...
by Diminished
Mon Oct 22, 2018 2:07 am
Forum: software: classic games
Topic: Citadel Disassembly / Reassembly v0.1
Replies: 12
Views: 1479

Re: Citadel Disassembly / Reassembly v0.1

Anyone get the impression Diminished likes the game Citadel? :D Well, the number of people willing and able to undertake disassembly of old BBC games has to be pretty small at this point, and it's only going to get smaller. I still don't understand how parts of the game work, but publishing what I ...
by Diminished
Wed Oct 10, 2018 9:00 pm
Forum: software: classic games
Topic: Citadel Disassembly / Reassembly v0.1
Replies: 12
Views: 1479

Re: Citadel Disassembly / Reassembly v0.1

streaks wrote:
Wed Oct 10, 2018 7:05 pm
Insane
I'm inclined to agree
by Diminished
Mon Oct 08, 2018 3:43 pm
Forum: software: classic games
Topic: Citadel Disassembly / Reassembly v0.1
Replies: 12
Views: 1479

Citadel Disassembly / Reassembly v0.1

Roll Your Own Citadel: citadel-reassembly-0.1-rc4.zip Here's the README: Citadel BBC Reassembly v0.1, 8th October 2018 Original game by Michael Jakobsen Disassembly / reassembly by 'Diminished' --- INTRO This is a set of files -- including reverse-engineered source code -- that will enable you to bu...
by Diminished
Sat Sep 29, 2018 5:25 pm
Forum: software: classic games
Topic: Unused Citadel bits
Replies: 71
Views: 7041

Re: Unused Citadel bits

Here's a patch which should be useful for working on this game. It modifies the game's "attract mode", so you can flick through every possible room ID from 0 to 255 by pressing the left and right keys at the title screen (Z and X if using control scheme 1). It also displays the displayed room ID in ...
by Diminished
Tue Sep 25, 2018 5:13 pm
Forum: software: classic games
Topic: Unused Citadel bits
Replies: 71
Views: 7041

Re: Unused Citadel bits

Rich: How would you set that up? Here is what the game does to draw that notorious Witch's House roof: 1 MODE 2 2 ?&306=&B0: REM OS gfx window R.H. column 3 ?&30B=&08: REM OS text window top row 4 ?&30E=&E0:?&30F=&FF: REM OS graphics origin (ext. coords) 5 ?&FE00=&6:?&FE01=&18: REM 6845 vertical dis...
by Diminished
Mon Sep 24, 2018 5:29 pm
Forum: software: classic games
Topic: Unused Citadel bits
Replies: 71
Views: 7041

Re: Unused Citadel bits

So, the triangles. In order to try to understand what is going on, I modified b-em to print out equivalent BBC BASIC statements every time it did something triangle-related with the OS (i.e. illegal MOVEs and legal PLOT 85s). I also did some digging to try to find out how the OS and CRTC are set up,...
by Diminished
Sun Sep 23, 2018 8:24 pm
Forum: emulators
Topic: b2 - new emulator
Replies: 114
Views: 10620

Re: b2 - new emulator

It should be working. There's supposed to be a dialog that pops up when you click the option... perhaps it could be appearing off the edge of the window or something? I've had a few problems like this with the docking/tabbing UI system I'm using :( Try going to Tools > Reset dock windows > Confirm,...