Search found 116 matches

by Kevin Edwards
Sun Mar 03, 2019 9:48 pm
Forum: software: classic games
Topic: Galaforce BBC Micro 6502 source code now available
Replies: 2
Views: 369

Galaforce BBC Micro 6502 source code now available

Hi, I have just released the 6502 source code for my BBC Micro game, Galaforce, from 1986. This was taken from the original master disks and adapted to build using BeebAsm on a PC. I hope this gives some insight into how games were made in the 1980s! You can find the details on my Twitter account:- ...
by Kevin Edwards
Fri Feb 08, 2019 7:51 pm
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 1132

Re: Lunar Jetman protection

It's quite amazing how I still remember most of this code from over 33 years ago - written when i was only 19. I wish my memory was as good now as it was then!

So BeebEM appears to have some issues with its 6522 TIMER emulation? I guess it's based on a very different code-base than b-em?

Kevin.
by Kevin Edwards
Thu Feb 07, 2019 11:24 pm
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 1132

Re: Lunar Jetman protection

Here's one of mine using the original code:-
LJRUN2.png
by Kevin Edwards
Thu Feb 07, 2019 11:20 pm
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 1132

Re: Lunar Jetman protection

Ah! Jolly good, it does get past all the protection.

What are those solid squares? They don't look right.
by Kevin Edwards
Thu Feb 07, 2019 10:59 pm
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 1132

Re: Lunar Jetman protection

The blockless 1200 baud data streams I used did put a lot of people off as they couldn't be loaded using the normal tape filing system. I did try to use faster baud rates, but I seem to remember the Serial ACIA 6850? wouldn't allow faster speeds for the tape system. So, are all the Beeb emulators un...
by Kevin Edwards
Thu Feb 07, 2019 8:42 pm
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 1132

Re: Lunar Jetman protection

Many thanks Diminished for grabbing, and going through that code. Yes, that all looks rather familiar. I'd almost forgotten about the REPLAY check. I think they released a later version of the device / software to get around my checks. I can see all the tricks I expected in there:- 1.) Stashing impo...
by Kevin Edwards
Wed Feb 06, 2019 3:35 pm
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 1132

Re: Lunar Jetman protection

How weird. I never noticed that before.

I wonder if it's because it uses 'offset' assembly and assembles the object code into sideways RAM. It looks like it's reading from the BASIC ROM?
by Kevin Edwards
Wed Feb 06, 2019 3:02 pm
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 1132

Re: Lunar Jetman protection

If you would like to see BBC Micro Lunar Jetman assembling from original source code this may be of interest:-

[ VIDEO on YouTube ]

https://www.youtube.com/watch?v=Eh6lgIx5By0&fe=


[ Screen Grabs ]
LJ_GRAB1.JPG
LJASM2.jpg
by Kevin Edwards
Wed Feb 06, 2019 2:49 pm
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 1132

Re: Lunar Jetman protection

I have dug out the original source code master disks for Nightshade and Lunar Jetman ( Paul Proctor's original disks ) They confirm that LunarJetman was finished around 27/9/1985. DSC_0255.JPG and Nightshade was finished around 16/10/1985 DSC_0256 - Copy.JPG Still not sure of the official release da...
by Kevin Edwards
Wed Feb 06, 2019 2:09 pm
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 1132

Re: Lunar Jetman protection

That fragment is part of the IRQ code, so the LDA &FC was just the start of the postamble, to restore A before doing RTI. OK. In that context the &FC access make total sense. The LDA &102,X grabs part of the return address from the stack and re-seeds the VIA timer just to make emulation / hacking e...
by Kevin Edwards
Wed Feb 06, 2019 9:32 am
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 1132

Re: Lunar Jetman protection

Hi Rich, I can't recall all of the detail as it was so long ago, but i'm guessing it was kind of 'mis-direction'. I wish I still had the source code! Without the correct values being read the de-cryption would produce incorrect results so i'm assuming it wasn't a bug and executed as intended, howeve...
by Kevin Edwards
Tue Feb 05, 2019 8:40 pm
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 1132

Re: Lunar Jetman protection

Cool. Thanks for posting the various images. It was quite common practice for me to make use of previously 'stashed' values in later stages of the protection. I would quite often put these values in volatile areas of memory that would get trashed is someone was breaking into the code via the BASIC i...
by Kevin Edwards
Tue Feb 05, 2019 1:14 pm
Forum: software: classic games
Topic: Lunar Jetman protection
Replies: 34
Views: 1132

Lunar Jetman protection

Hi, Following on from the Nightshade protection thread , did anyone manage to crack Lunar Jetman and put it on disk? I remember it having some quite nasty protection, but can't remember if it was quite as painful as Nightshade's. In fact, I can't remember which title was released first - i'm assumin...
by Kevin Edwards
Mon Nov 26, 2018 12:35 pm
Forum: software: other
Topic: Source code for OS1.2, BBC Basic and other Acorn software
Replies: 6
Views: 763

Re: Source code for OS1.2, BBC Basic and other Acorn software

Many thanks, Jonathan for the extra links - and for the magnificent work you have done on your site! The BasPlus code is really interesting - part of that looks very similar to the code I saw back in the late 80s. Time for a good browse through it all. Did you re-create the 8-bit basic source code v...
by Kevin Edwards
Sun Nov 25, 2018 7:08 pm
Forum: software: other
Topic: Source code for OS1.2, BBC Basic and other Acorn software
Replies: 6
Views: 763

Re: Source code for OS1.2, BBC Basic and other Acorn software

Thanks for the links. The JGH annotated BBC Basic dissassemblies are great. A lot of effort has been put into the creation of those images! Still got my fingers crossed that someone has the original ones by Sophie. Possibly an ex-Acorn staff member or 'friends-of' Acorn staff have copies. I think I ...
by Kevin Edwards
Sun Nov 25, 2018 3:49 pm
Forum: software: other
Topic: Source code for OS1.2, BBC Basic and other Acorn software
Replies: 6
Views: 763

Source code for OS1.2, BBC Basic and other Acorn software

Hi, I was wondering if anyone has any original Acorn / Acornsoft source code for the BBC Micro and Electron - BBC Basic and OS in particular. I seem to remember having a conversation with someone many years ago and them mentioning that OS1.2 and Basic 2 / IV source had been preserved. I'm sure they ...
by Kevin Edwards
Sun Nov 11, 2018 12:42 pm
Forum: software: classic games
Topic: Crazee Rider 6502 source code now available
Replies: 10
Views: 829

Re: Crazee Rider 6502 source code now available

Hi, I have updated the BBC Micro Crazee Rider source code archive to include the original source code disk image ( .dsd ). The latest update information can be found here:- https://twitter.com/KevEdwardsRetro The repository now contains the original BBC BASIC tokenised source code files that can be ...
by Kevin Edwards
Wed Nov 07, 2018 10:58 pm
Forum: software: classic games
Topic: Crazee Rider 6502 source code now available
Replies: 10
Views: 829

Re: Crazee Rider 6502 source code now available

Hi Rich, I used bas2txt.exe then spent quite a few hours stripping out the BBC BASIC stuff and substituting the BeebAsm directives. It took me a bit of time to work out the relevant commands then it was fairly easy - I think you covered most of the things I needed to do which made the job straightfo...
by Kevin Edwards
Mon Nov 05, 2018 9:56 pm
Forum: software: classic games
Topic: Crazee Rider 6502 source code now available
Replies: 10
Views: 829

Crazee Rider 6502 source code now available

Hi, I have just released the 6502 source code for my BBC Micro game, Crazee Rider, from 1987. This was taken from the original master disks and adapted to build using BeebAsm on a PC. I hope this gives some insight into how games were made in the 1980s! You can find the details on my Twitter account...
by Kevin Edwards
Tue Aug 21, 2018 9:43 am
Forum: projects
Topic: Twisted Brain Demo
Replies: 38
Views: 3592

Re: Twisted Brain Demo

Is BeebEm still being actively maintained? It would be nice if the cycle timings could be fixed to bring it up-to-date like B-Em ( big ask I know). I know some of my 6522 critical stuff fails on BeebEm. It also fails to run ( unprotected ) LunarJetman correctly - it uses 6522 timiers for a split scr...
by Kevin Edwards
Tue Aug 21, 2018 9:32 am
Forum: software: new games
Topic: Galaforce 3 Teaser
Replies: 11
Views: 1130

Re: Galaforce 3 Teaser

The original BBC games supported Joystick IIRC. The Electron version also supported the 'First-Byte' joystick.
by Kevin Edwards
Tue Aug 21, 2018 8:56 am
Forum: software: classic games
Topic: Mystery of the missing Exile mail-in cards
Replies: 7
Views: 999

Re: Mystery of the missing Exile mail-in cards

Yes, i received both cards in my copy.
exline_cards_small.JPG
by Kevin Edwards
Tue Jul 17, 2018 10:08 pm
Forum: development tools
Topic: Beebasm requests
Replies: 9
Views: 714

Re: Beebasm requests

Thanks Rich for the code changes. I shall plug them in. I may have a go at implementing the A% to Z% variables, but my time is in short supply at present. Cheers, tricky for details about your build process. Looks like something i will investigate once i've got the current project in a buildable sta...
by Kevin Edwards
Tue Jul 17, 2018 12:28 pm
Forum: development tools
Topic: Beebasm requests
Replies: 9
Views: 714

Re: Beebasm requests

COPYBLOCK, sounds interesting! Can't find it in the docs, but noticed it in the version history.
Not that i'd ever use it for any hackery :lol:
by Kevin Edwards
Tue Jul 17, 2018 12:15 pm
Forum: development tools
Topic: Beebasm requests
Replies: 9
Views: 714

Re: Beebasm requests

Hi Rich, Thanks for the quick response. I can see why re-definable 'normal' variables would be problematic! If support for A% to Z% could be added then that would be so cool. I also use B% below to keep track of the start of the code block in each source file so i can see how large each block of obj...
by Kevin Edwards
Tue Jul 17, 2018 12:02 pm
Forum: projects
Topic: Elite BeebAsm Source
Replies: 17
Views: 1223

Re: Elite BeebAsm Source

Awesome work, Kieran!

I remember looking through the original code years ago and it made my eyes bleed! Not because I didn't follow the code, but because of the (lack of) formatting and the short labels etc.

Must re-visit it and have a play.

Cheers,
Kevin.
by Kevin Edwards
Tue Jul 17, 2018 11:46 am
Forum: development tools
Topic: Beebasm requests
Replies: 9
Views: 714

Beebasm requests

Hi, I'm not sure if this is the right place for Beebasm requests, hopefully it is. Basically, i'm moving some old BBCBasic style 6502 assembly source code over to beebasm and found that it would be really useful if there were some re-definable variables that i could make use of - A% to Z% would be i...
by Kevin Edwards
Wed Jul 11, 2018 12:09 pm
Forum: software: new games
Topic: Galaforce 3 Teaser
Replies: 11
Views: 1130

Galaforce 3 Teaser

It's been 30 years since Galaforce 2 was completed. Here's something I've been tinkering with. An updated version of Galaforce 2 for 2018. Galaforce_3_Teaser_grab.jpg Video can be found here https://youtu.be/wg_UPyQM6eA More Beeb related Stuff on Twitter https://twitter.com/KevEdwardsRetro .
by Kevin Edwards
Mon Jun 25, 2018 9:42 pm
Forum: adventures
Topic: Search for the Lost Orb
Replies: 16
Views: 1363

Re: Search for the Lost Orb

Yes, Andy co-wrote the AUG. IIRC The authors were all at Cambridge, but at different colleges when they wrote the AUG. This adventure was several years later i believe when Andy worked for Acorn as a contractor around 1986/7. Sadly, I lost touch with him shortly afterwards so can't ask him if he kno...
by Kevin Edwards
Sun Jun 24, 2018 11:34 am
Forum: adventures
Topic: Search for the Lost Orb
Replies: 16
Views: 1363

Re: Search for the Lost Orb

Hi guys, I've done a bit more digging and have remembered a bit more about the disk. I knew a lot of people who developed Beeb games and a Cambridge connection is quite possible - Acorn / Acornsoft? I travelled to Cambridge and London quite a bit during 1985-87 so i'm guessing I picked it up during ...