Search found 618 matches

by kieranhj
Thu May 17, 2018 1:37 pm
Forum: programming
Topic: BASIC 2 Commented Disassembly
Replies: 6
Views: 307

Re: BASIC 2 Commented Disassembly

Seems like this was a popular passtime in the 80's. Here's Kevin Edwards talking about it: https://twitter.com/KevEdwardsRetro/status/996831345866309632?s=20
by kieranhj
Mon May 14, 2018 9:50 pm
Forum: emulators
Topic: Video Timing
Replies: 31
Views: 1069

Re: Video Timing

I feel like this can also be explained by the same issue as tricky's problem, here . Have I understood right that you have a bunch of single line, single row CRTC frames (R4=0, R9=0), and then a block of rows to make the PAL frame up to 312? In the other thread, we have the observation that R4 need...
by kieranhj
Mon May 14, 2018 5:37 pm
Forum: emulators
Topic: Video Timing
Replies: 31
Views: 1069

Re: Video Timing

This would imply that, for some 6845s, you could set R12/R13 at different scanlines within the first character row of a new frame and get a change of address midway through a row. Doesn't it? Not that this is related to your problem, but it's probably worth considering all the same, if it's true. I...
by kieranhj
Mon May 14, 2018 5:00 pm
Forum: other vintage computer hardware, software and games
Topic: Some Apple II's needing TLC at Hampshire ABUG
Replies: 6
Views: 193

Re: Some Apple II's needing TLC at Hampshire ABUG

I also have an Apple IIe that I have (shamefully :oops: ) never attempted to turn on since obtaining it from eBay. If there is going to be a small Apple II corner then I will bring this along as well, if that's OK? (This is assuming I make it to ABUG at all, it's a bit touch & go with work at th...
by kieranhj
Thu May 10, 2018 11:59 am
Forum: software: classic games
Topic: My final unanswered Exile question
Replies: 61
Views: 2647

Re: My final unanswered Exile question

I struggle to imagine how it could be much better than it already is. However I do have a practical suggestion, which is whether it could be ported to the 6502 second processor. This would free up a lot of memory which could be used for more sound samples perhaps? That's an interesting idea, whethe...
by kieranhj
Thu May 10, 2018 11:26 am
Forum: software: classic games
Topic: My final unanswered Exile question
Replies: 61
Views: 2647

Re: My final unanswered Exile question

If it were up to me, I'd have a separate Exile subforum! :) :D Without wanting to trigger a mega-thread, VectorEyes & I were discussing what an Exile 2 might look like, perhaps if it was Master only... or whether the original game is considered the beautiful pinnacle of 6502 game engineering (o...
by kieranhj
Sat May 05, 2018 7:04 pm
Forum: software: new games
Topic: New version of Scramble for the beeb (just starting)
Replies: 33
Views: 1526

Re: New version of Scramble for the beeb (just starting)

Looks nice and smooth Tricky, great work as always! Just so I’m clear what you’re doing here - this is 1 pixel scrolling in MODE 1 by pre-calculating all of the tile offsets in the sequence in which they appear across all of the maps? Then presumably redrawing all of the background tiles each frame ...
by kieranhj
Sat May 05, 2018 4:10 pm
Forum: software: classic games
Topic: My final unanswered Exile question
Replies: 61
Views: 2647

Re: My final unanswered Exile question

On the subject of Exile - what would have to be done to make the game scroll smoothly? The jerky-scrolling has never annoyed me, but I was thinking that with new add-ons like the VideoNula, would it be possible to recode the game to smooth things out? I always assumed the jerky scrolling was down t...
by kieranhj
Wed May 02, 2018 9:39 pm
Forum: projects
Topic: Going great guns on a Prince of Persia port...
Replies: 224
Views: 20054

Re: Going great guns on a Prince of Persia port...

I did promise everyone a memory map of the game. RobC has prompted me to do this so here's a first attempt: -------- POP-BEEB MEMORY MAP -------- -------- ZERO PAGE -------- &0000 - &00FF: ZERO PAGE -------- Zero page high watermark = &A0 Zero page free = &0 -------- Global variables...
by kieranhj
Mon Apr 23, 2018 11:26 am
Forum: emulators
Topic: Video Timing
Replies: 31
Views: 1069

Re: Video Timing

The overall context here is that we have reached the end of a scanline, i.e. hc == R0 so this is where it does various vertical control things. These are the only references to R12/13 so this looks like resetting the current memory address back to the start address in R12/13 at the end of vadj. Tha...
by kieranhj
Sun Apr 22, 2018 8:54 pm
Forum: emulators
Topic: Video Timing
Replies: 31
Views: 1069

Re: Video Timing

This is a really interesting thread, thanks for all the links and info. It is quite timely (pun intended?!) as I’m currently writing a new BBC Master demo that is all based around reprogramming the CRTC liberally. If you want to test anything I have a framework that runs code exactly at the start of...
by kieranhj
Thu Apr 19, 2018 10:24 am
Forum: upcoming and recent events & exhibitions
Topic: Wakefield RISC OS show 21st April 2018
Replies: 57
Views: 2935

Re: Wakefield RISC OS show 21st April 2018

If anyone has chance to show off POP on a real Master that would be much appreciated!

PS. Don’t forget you can turn down the volume.
by kieranhj
Mon Apr 16, 2018 7:54 pm
Forum: software: new games
Topic: Prince of Persia
Replies: 105
Views: 4056

Re: Prince of Persia

Glad you’re enjoying the game! Yes, it is nails hard by modern standards. Those used to the PC version might still find the original Apple II code a bit challenging - partly because the frame rate is more errratic, so some of the busy levels later on get a bit painful, but I also think they added so...
by kieranhj
Thu Apr 12, 2018 5:49 pm
Forum: hardware
Topic: A blitter for the beeb?
Replies: 59
Views: 4198

Re: A blitter for the beeb?

1024MAK wrote:Although after watching the video, all I could think of was 'speaker in a cardboard box productions' :lol:

I was admiring the Sony reference monitors - very nice! Careful though, you’ll be triggering sbadger’s CRT fetish. :lol:

But yes, great work Dominic, very interesting.
by kieranhj
Wed Apr 11, 2018 9:50 pm
Forum: software: new games
Topic: Prince of Persia
Replies: 105
Views: 4056

Re: Prince of Persia

Works a treat, thanks! It somehow seems more real when running it on real hardware. This game is also a lot more playable if you actually bother to read the instructions ;) Yay! Glad that worked. Some people have mentioned that the music is very loud on real hardware - don’t forget you can reduce t...
by kieranhj
Wed Apr 11, 2018 5:53 pm
Forum: software: new games
Topic: Prince of Persia
Replies: 105
Views: 4056

Re: Prince of Persia

This is impressive stuff! Played it in B-Em and managed to get to the second level, at least. Unfortunately I can't get it working on my real Master - I have my 3.5" drive set up as drive 1 and 3, and my drive 0 is a 40 track 5.25" drive. I wrote it to a 3.5" disc using Omniflop, but...
by kieranhj
Fri Apr 06, 2018 8:27 pm
Forum: programming
Topic: Acorn files on other platforms
Replies: 38
Views: 1512

Re: Acorn files on other platforms

Are you aware of Stephen's mmb_utils? https://sweh.spuddy.org/Beeb/mmb_utils.html https://github.com/sweharris/MMB_Utils They are written in perl, but run happily on Windows. I use these for the packaging phase in all of my projects. They are also small enough to be checked in to git, which removes...
by kieranhj
Wed Apr 04, 2018 10:04 pm
Forum: general
Topic: Can the BBC stream full motion video?
Replies: 32
Views: 1004

Re: Can the BBC stream full motion video?

Because we had to solve streaming from floppy for a Bad Apple, I did some experiments with non-Teletext video for fun a while back m: http://www.stardot.org.uk/forums/viewtopic.php?f=53&t=13473 I do like that MODE 2 idea of using the top unused bits, worth pondering again. I think the biggest ch...
by kieranhj
Tue Apr 03, 2018 7:09 pm
Forum: programming
Topic: Acorn files on other platforms
Replies: 38
Views: 1512

Re: Acorn files on other platforms

Perhaps some motivating examples would help. BeebAsm focuses on outputting a .ssd rather than a bare executable. That feels very much like two tools have been combined into one: I'd like to be able to assemble some executables, save some BASIC, write a bit of *EXEC, storing them all in some format ...
by kieranhj
Sun Apr 01, 2018 7:46 pm
Forum: software: new games
Topic: Prince of Persia
Replies: 105
Views: 4056

Re: Prince of Persia

I`ve pushed a v1.1 build to GitHub so should now be on the POP page on our Bitshifters site: https://bitshifters.github.io/posts/prods/bs-pop-beeb.html . This should fix the known crashes. I'll ponder the other requests and issues over the coming week. If you experience any more crashes or other bug...
by kieranhj
Sun Apr 01, 2018 7:02 pm
Forum: software: new games
Topic: Prince of Persia
Replies: 105
Views: 4056

Re: Prince of Persia

EDIT 2: in the 1.0 build, there's a JMP &2055 situated at &2501 which looks like the culprit, doing a jump into a routine without fixing the stack first. I tried inserting this nasty hack into b-em's m65c02_exec(): Winner winner, chicken dinner! This is the call to RESTART that happens in t...
by kieranhj
Sun Apr 01, 2018 4:31 pm
Forum: software: new games
Topic: Prince of Persia
Replies: 105
Views: 4056

Re: Prince of Persia

I think I have it. Every time you die and press enter to restart the level, the stack pointer starts 6 bytes lower than it did last time the level was loaded. Logic suggests this isn't a sustainable situation. You sir, are a star! I will investigate this finding later on and compare against the ori...
by kieranhj
Sun Apr 01, 2018 10:07 am
Forum: software: new games
Topic: Prince of Persia
Replies: 105
Views: 4056

Re: Prince of Persia

OK! Four more playthroughs (on the test build this time), and it crashed on the final one. But I got the receipts! This is a b-em 2.2 savestate: popsavestate.zip Before I started, I had the sense to patch the emulator to allow me to save state from its debugger -- so I was able to dump the state ri...
by kieranhj
Sat Mar 31, 2018 10:08 pm
Forum: software: new games
Topic: Prince of Persia
Replies: 105
Views: 4056

Re: Prince of Persia

For anyone interested, I've done a quick build to fix the known scribble (not an official release!), you can test it here: https://bitshifters.github.io/jsbeeb/?disc=https://bitshifters.github.io/content/wip/pop-beeb-scribble-fix.ssd&autoboot&model=Master Or download the image: https://bitsh...
by kieranhj
Sat Mar 31, 2018 8:59 pm
Forum: software: new games
Topic: Prince of Persia
Replies: 105
Views: 4056

Re: Prince of Persia

Once again, here are ZP and the stack: 0100 a1 a1 90 ed f9 ee 30 a1 ......0. 0108 3d 8f 21 8c ca 8b 1c 94 =.!..... 0110 df 93 94 82 00 27 82 df .....'.. 0118 87 1e 84 02 ed ff 8c ff ........ 0120 1c 80 1d ff 51 fa 18 17 ....Q... 0128 48 18 5b 18 df 28 04 a7 H.[..(.. 0130 1e 57 1d a0 24 f1 21 44 .W....
by kieranhj
Sat Mar 31, 2018 7:47 pm
Forum: software: new games
Topic: Prince of Persia
Replies: 105
Views: 4056

Re: Prince of Persia

I've dusted off the Master now, and I've been suitably blown away by how impressive and beautiful it is! My two boys played it for most of the afternoon and nearly completed Level 2. Thank you. It is quite difficult though, they don't make them like that (hard) any more!! I'm running it from MMFS a...
by kieranhj
Sat Mar 31, 2018 7:45 pm
Forum: software: new games
Topic: Prince of Persia
Replies: 105
Views: 4056

Re: Prince of Persia

the game slowed down a lot for the duration of the music. ... then it crashed when I ran through the door that triggers the ending cinematic. Once again, here are ZP and the stack: 0100 a1 a1 90 ed f9 ee 30 a1 ......0. 0108 3d 8f 21 8c ca 8b 1c 94 =.!..... 0110 df 93 94 82 00 27 82 df .....'.. 0118...
by kieranhj
Sat Mar 31, 2018 6:17 pm
Forum: software: new games
Topic: Prince of Persia
Replies: 105
Views: 4056

Re: Prince of Persia

Great job! I'm having trouble getting it to run on my real master. I got screen corruption instead instead of the intro (Two bars at the top and bottom). Both LK19 and 18 are west, and I have *unplugged everything. I had a retroclinic multi OS installed switched to 3.20 mode. Do you have *DTRAP ena...
by kieranhj
Sat Mar 31, 2018 5:41 pm
Forum: software: new games
Topic: Prince of Persia
Replies: 105
Views: 4056

Re: Prince of Persia

I wonder if a Master emulator for the Pi co-pro would be an option. It might be possible to overcome the lack of (displayable) shadow screen by getting the Pi to do the heavy lifting and only send differences across the Tube... This isn't as outlandish as it first sounded to me. The game spends a l...
by kieranhj
Sat Mar 31, 2018 5:34 pm
Forum: software: new games
Topic: Prince of Persia
Replies: 105
Views: 4056

Re: Prince of Persia

OK, I got another one. Unfortunately this was in Firefox again, but I'll probably do another few playthroughs on b-em to see if I can convince it to misbehave in that emulator. Hopefully I won't die twelve times on Level 8 next try. Once again, here are ZP and the stack: <snip> Thanks for the bug r...