Search found 781 matches

by Dave Footitt
Tue Jul 04, 2006 2:59 pm
Forum: off-topic
Topic: 80s Music Videos
Replies: 9
Views: 2289

Ahhh Sabrina :shock: :lol:
by Dave Footitt
Sun Jul 02, 2006 2:42 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Could someone explain to me how I copy/paste from an emulator please? Hi Guy What I did was got hold of the EXMON II rom (pretty decent). Then, created a new disc image using DFS Explorer. Mounted this image in BeebEm and also mounted the "GoldDigger" tape image (Lousy game, by the way). ...
by Dave Footitt
Sun Jul 02, 2006 11:21 am
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Aha, great stuff. Just found the debugger setting in the emulator!

Thanks a lot


Dave
by Dave Footitt
Sat Jul 01, 2006 8:34 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Yeah it's good... Having trouble following some of this code though. What do you use for debugging this stuff? Is there a way to emulate reading these bitstreams off tape and singlestepping through with a debugger? I can't, for instance, find out where some of the routines get called at all, from &a...
by Dave Footitt
Sat Jul 01, 2006 8:19 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Aha yes. It's OSASCI.

The 2 writes to the 6850 &08 are for initialising (The &03) and then setting up baud rate (&19).

Can you tell I've dug out my advanced user guide? :)
by Dave Footitt
Sat Jul 01, 2006 6:12 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

And the printing routine at &7A2A.. Should that be JSR &FFEE instead of &FFE3?

Quite complicated really, I don't really understand the 6850 gubbins but I'll keep looking :)
by Dave Footitt
Sat Jul 01, 2006 4:07 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Re: Firebird disassembly

I think that's right, anyone want to check it? (especially where addresses are called/looped to) Hi Guy Have you typed this in? Just started to read it through to re-famaliarise myself with 6502 and the good old Beeb. Noticed there's a JST instruction - I've not heard of that :? Further down too at...
by Dave Footitt
Fri Jun 30, 2006 8:14 am
Forum: software: classic games
Topic: SIM
Replies: 9
Views: 3208

Can only remember the odd screen, it was quite hard.

Post a screenshot of the room perhaps, see if it's the same one?

Might dig it out today :)
by Dave Footitt
Thu Jun 29, 2006 4:44 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Edit: The original Nightshade tapes with the head cleaner are pretty rare these days, I bought a Ricochet re-release on Ebay. Always the way, everything I throw away becomes valuable. Don't get me started on Star Wars figures ;) I do still have my original Sabre Wulf, Chuckie Egg and Manic Miner ta...
by Dave Footitt
Thu Jun 29, 2006 4:22 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Interesting stuff. I bought Nightshade, I remember it came with a free tape head cleaner. Probably for the amount of wear your tape would get trying to crack it ;)

Out of interest, how come you're messing about with your own protection system these days? Just for kicks?


Dave
by Dave Footitt
Thu Jun 29, 2006 4:09 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Hehe ace, old Kev's a bit handy is he?

Did anyone crack Nightshade then?

I have the Advanced User Guide at home somewhere, I bought it on eBay ages ago and not looked since, I might dig it up, I've already shown myself to be a bit 6502 rusty :oops:
by Dave Footitt
Thu Jun 29, 2006 3:53 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Gauntlet. Well, thats diff in my book (specy ver). A much better version than Defender/Planetoid, played it first on the electron :wink: Think we may have our wires crossed - I meant Gauntlet as in Atari Gauntlet, the 4 player hack and slash "Elf is about to die" type lark :) Anyone care ...
by Dave Footitt
Thu Jun 29, 2006 3:41 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

One other game I just remembered from the past - Dunjunz. The tape version seemed to transfer to disc fine, but crashed on level 2 or something. Only vague memories of that, but that was a fairly well implemented version of Gauntlet. Not sure why it crashed on level 2, if it was a crafty protection ...
by Dave Footitt
Thu Jun 29, 2006 3:34 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Yep, top game. There were some belters back then.

Not heard of Space HiWay either :)
by Dave Footitt
Thu Jun 29, 2006 3:18 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

OK pretty much there now :)

Code: Select all

SEI
LDX #0
STX &FE68
STX &FE69


I can't remember what SEI does, something to do with interrupts?

I'm assuming FE68/9 are some memory-mapped VIA registers?


Dave
by Dave Footitt
Thu Jun 29, 2006 3:15 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Why not, the more the merrier :)

I've not checked the VIA stuff yet so I might have more questions ;)


Dave
by Dave Footitt
Thu Jun 29, 2006 2:59 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Aha. Not got down to the timer stuff yet - Reading at work so can't spend too long on it :) You still working on Beeb stuff then? I do remember buying Wizadore, that had some protection on it or other, and I obtained a version on disc cracked by "Flobadobb Cuckadoo" or something, heheh, ha...
by Dave Footitt
Thu Jun 29, 2006 2:54 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Next level of difficulty:add self modifying code: (this is a piece of code I've recently implemented) E00 LDX #0 .XLOOP LDA &E00,X STA &70 STX &71 LDY #0 .YLOOP LDA NEXT,Y EOR &70 EOR &71 .Y2 STA NEXT,Y INY BNE YLOOP INC YLOOP+1 INC Y2+1 INX BNE XLOOP This is more difficult beca...
by Dave Footitt
Thu Jun 29, 2006 2:25 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

If we have a piece of code like this: .START LDX #0 .XLOOP LDA START,X EOR NEXT,X STA NEXT,X INX BNE XLOOP where .NEXT is the next page in memory... [snip] So, you'd look at what the above assembled to, then pre-xor your NEXT page with these bytes? I'm assuming a "page" is 256 bytes? Dave
by Dave Footitt
Thu Jun 29, 2006 1:38 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

The addresses &220/&221 are for user defined interrupts and the *fx commands turn this off (13,4) and on (14,4). I did this so that modifying the program doesn't cause the machine to crash. Very useful to code 6502 in BBC BASIC! Superb stuff Guy! As soon as I saw those addresses it rang an ...
by Dave Footitt
Thu Jun 29, 2006 1:28 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Thanks Guy

Yeah I'm on about the original BBC, I don't yet have BeebEm.

The piece of 6502 you wrote there - how would I apply that? ie How would I create the interrupt to run that code?

(Sorry if this is obvious, I just like to know exactly how to do things!)
by Dave Footitt
Thu Jun 29, 2006 1:06 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Well he did say "Locked ain't a problem", which would suggest that it can be got around quite easily?

In which case how? Is "Locked" the exact same thing as having the bit set in the tape header?
by Dave Footitt
Thu Jun 29, 2006 12:59 pm
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

CMcDougall wrote:"Locked" aint a problem, plenty progs that will allow it to *L. "" 2000 :wink:


Sorry, I'm a bit lost, what do you mean? Locked files can be loaded if you simply specify an address to load them to?
by Dave Footitt
Thu Jun 29, 2006 10:15 am
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Excellent replies Guy, spot on what I was after.

I do understand 6502 but it's been a while since I've used a BBC, I'd forgotten about the "Locked" business!

Much appreciated,


Dave
by Dave Footitt
Thu Jun 29, 2006 9:32 am
Forum: software: classic games
Topic: Protection for dummies
Replies: 69
Views: 12840

Protection for dummies

Hi I've been reading the Nightshade protection thread, some interesting stuff on there. However, it's been a while since I've used a Beeb, and am interested in a basic overview of how these protection systems work. Forgive me if these are obvious questions :) * The basic idea - Is it just to stop ta...
by Dave Footitt
Tue Jun 27, 2006 10:23 am
Forum: software: classic games
Topic: SIM
Replies: 9
Views: 3208

SIM

Anyone remember that crackers game SIM?

I can barely remember having to collect little simarals (or something) and then dropping them off in a room.

I spent quite a bit of time on it - Anyone finish it?


Dave
by Dave Footitt
Mon Jun 26, 2006 4:41 pm
Forum: software: classic games
Topic: Coding Discussion
Replies: 4
Views: 1796

Yeah why not, fire away lad
by Dave Footitt
Sun Jun 25, 2006 12:07 pm
Forum: for sale / freebies
Topic: Electron User magazines, Acorn Electron accessories and more
Replies: 9
Views: 4267

I have 3 issues of Electron User:

Vol 4 No 1 (October 1986)
Vol 2 No 12 (September 1985)
Vol 3 No 2 (November 1985)

All reasonable condition. Free to a good home, PM me if anyone wants them :)
by Dave Footitt
Sun Jun 25, 2006 11:47 am
Forum: software: classic games
Topic: Most advanced BBC game?
Replies: 40
Views: 14964

I think Citadel is one of the most underrated BBC games technically. It fitted in absolutely masses and used some very clever techniques to do so. I like the way it's graphics were stored, and how it coped with making things climable or deadly to touch. I agree, I loved Citadel, although never fini...
by Dave Footitt
Fri Jun 23, 2006 9:36 am
Forum: software: classic games
Topic: Most advanced BBC game?
Replies: 40
Views: 14964

Not sure, I think it came out on most 8 bits at the same time, so I'd have thought it was wrote on one of those. Can't fault the lad for putting the effort in of dithered filled polys and matrix/vector operations in 6502!