Search found 783 matches

by paulb
Mon Dec 11, 2017 8:44 pm
Forum: software: classic games
Topic: Unused Citadel bits
Replies: 20
Views: 741

Re: Unused Citadel bits

Arcadian -- I don't think a non-garbaged Electron version would be possible, unfortunately. The BBC version just reprograms the ... CRTC (??) ... to mask off those garbage areas. If the Electron doesn't have the hardware to do this, I don't think it's possible. You would need to save several kiloby...
by paulb
Sun Dec 03, 2017 7:37 pm
Forum: wanted
Topic: Would like to borrow: Hydra controller card
Replies: 15
Views: 574

Re: Would like to borrow: Hydra controller card

RISC OS was the operating system running on the Acorn computers ARM used to perform the demonstrations. This fact proves RISC OS was and is perfectly capable of multi-core operation. I'd be very surprised if that was ever the case. :roll: Maybe someone should tell ROOL, then, if it's that easy: Bou...
by paulb
Wed Nov 29, 2017 12:40 pm
Forum: hardware
Topic: A blitter for the beeb?
Replies: 40
Views: 1477

Re: A blitter for the beeb?

tricky wrote:I'm pretty sure that the NES 1983 had DMA and I seem to remember a thread around here about, I think DMA ideas for the elk.


DMA on the Electron
by paulb
Tue Nov 28, 2017 11:14 pm
Forum: hardware
Topic: A blitter for the beeb?
Replies: 40
Views: 1477

Re: A blitter for the beeb?

I remember the day we took delivery of our first Master 128 at school and being rather disappointed at the same 8 gaudy colours and lack of graphical improvements. Acorn's development focus was elsewhere, but at the time, the way the classic Beeb range was being stretched out was justifiably critic...
by paulb
Tue Nov 28, 2017 4:51 pm
Forum: hardware
Topic: A blitter for the beeb?
Replies: 40
Views: 1477

Re: A blitter for the beeb?

It seems clear to me that the address lines are _not_ released but _held_ (otherwise the slow ROM thing wouldn't work). Later processors in the series, I'm not sure when but certainly some WDC, have a BE input that when (de)asserted releases all the relevant lines. Whereas it is my understanding th...
by paulb
Tue Nov 28, 2017 3:40 pm
Forum: hardware
Topic: A blitter for the beeb?
Replies: 40
Views: 1477

Re: A blitter for the beeb?

I do use /RDY and /SYNC to hold the CPU. However, I also need to detach the CPU's address lines when blitting to/from system RAM as there is no way to tell an NMOS cpu to leave go the address and RnW lines. That's why at the moment it lives in the CPU socket. So unless there is some way of taking o...
by paulb
Tue Nov 28, 2017 1:53 pm
Forum: hardware
Topic: A blitter for the beeb?
Replies: 40
Views: 1477

Re: A blitter for the beeb?

On the Electron, you'd probably want to detect periods where the ULA isn't wanting to access RAM itself, and this might be easier in modes 0 to 3 because the CPU clock would actually be suspended and thus the test for ULA activity would be much easier. I just remembered that since the DMA controlle...
by paulb
Tue Nov 28, 2017 12:20 pm
Forum: hardware
Topic: A blitter for the beeb?
Replies: 40
Views: 1477

Re: A blitter for the beeb?

I started work a while back on a basic DMA controller and basic sound chip for my mk.2 6809 project which over the past month has morphed into a blitter chip for the BBC Micro. (For those who haven't heard of a blitter it is a chip that can copy memory from one place to another very quickly and opt...
by paulb
Mon Nov 27, 2017 10:15 pm
Forum: stardot.org.uk
Topic: https certificates?
Replies: 41
Views: 1629

Re: https certificates?

That's fundamentally missing the whole point of encryption - using Tor or a VPN you're just allowing people at the Tor/VPN end point to view the traffic. This really does need emphasising. Tor is largely intended to obscure the origin of traffic, not to protect that traffic from eavesdropping. And ...
by paulb
Mon Nov 27, 2017 8:59 pm
Forum: hardware
Topic: Acorn M4
Replies: 6
Views: 249

Re: Acorn M4

The chronology might be interesting here. Perhaps people were porting Unix to the ARM a lot earlier than we thought The first attempt was based around the Mach microkernel, and I just bet it happened around the same time as RISC OS Gold and the Victoria project - their moonshot was a rival for the ...
by paulb
Mon Nov 27, 2017 5:31 pm
Forum: hardware
Topic: Acorn M4
Replies: 6
Views: 249

Re: Acorn M4

Obligatory Chris's Acorns link which for once doesn't have much information. The chronology might be interesting here. Perhaps people were porting Unix to the ARM a lot earlier than we thought, in that it seemed from what people have said at various times and things like job adverts, Acorn seemed t...
by paulb
Thu Nov 23, 2017 12:01 pm
Forum: emulators
Topic: Clock Signal: now also for Linux and BSD
Replies: 10
Views: 310

Re: Clock Signal: now also for Linux and BSD

It similarly properly models the Electron output as interlaced, and obeys all of Paul Boddie's other observations as to behaviour . Nice to see you doing more emulator work, Thomas! I hope my observations are still valid given hoglet's heroic investigations with FPGA implementations, given that my ...
by paulb
Wed Nov 22, 2017 3:24 pm
Forum: hardware
Topic: Open Source Logic Analyzer Experiments
Replies: 98
Views: 3635

Re: Open Source Logic Analyzer Experiments

Maybe for a master machine version, it would be easier to create a bare cartridge with the required lines straight onto the board, or into sockets on the cartridge so the cypress board can be mated to the cartridge. Would probably have to be careful with the clearance for the board and the slot cov...
by paulb
Tue Nov 21, 2017 2:54 pm
Forum: projects
Topic: Going great guns on a Prince of Persia port...
Replies: 159
Views: 10422

Re: Starting a Prince of Persia port...

Separate the player sprites into 1bpp planes and only use 2 colours. A "large" one at the original sprite dimensions for the white pixels (~50% size give or take byte padding) and a second "small" one that is offset for the skin tone (currently magenta) pixels. This reminds me o...
by paulb
Mon Nov 20, 2017 3:22 pm
Forum: off-topic
Topic: Work experience BITD - claims to fame, and infamy
Replies: 11
Views: 432

Re: Work experience BITD - claims to fame, and infamy

In a commercial sense, that plainly worked for them, but it bears mentioning that until 1998 ARM hadn't succeeded in designing a CPU: StrongARM was designed by DEC, ARM6 and ARM7 were ARM2/3 in a fedora and dark glasses, ARM8 was a mess. In effect, they spent the first eight years of their existenc...
by paulb
Sun Nov 05, 2017 11:44 pm
Forum: software: classic games
Topic: "Unfixable bug" in BBC B Elite
Replies: 54
Views: 3590

Re: "Unfixable bug" in BBC B Elite

Well, I don't know as I never read any of that and how much they took or just used to build on, but there comes a point where it is normal to use what is there, in what should after many years be, the 'public domain'... Well, I'm sure things will get more interesting if Harry Potter ever shows up i...
by paulb
Sat Nov 04, 2017 12:21 pm
Forum: off-topic
Topic: Alternate Universe Micros...
Replies: 17
Views: 681

Re: Alternate Universe Micros...

In my alternate universe, some CEO would have had the idea start a group to produce loss-leader riser-type modems to get all the 80s kids on the bulletin boards, with better takeups of WIMP environments to operate software. FAR fewer headaches, say, for ordinary kids stressed out at the mere though...
by paulb
Tue Oct 31, 2017 1:54 pm
Forum: general
Topic: Who saw the BBC II Micro?
Replies: 8
Views: 383

Re: Who saw the BBC II Micro?

Reading through that issue I was surprised by the number of adverts, reminiscent of how later publications like Computer Shopper would have tons of adverts before you reached the editorial content, and by the apparent eagerness amongst vendors to sell 3-inch disk drives. It is possible that some of ...
by paulb
Sat Oct 28, 2017 12:20 pm
Forum: software & utilities for the pc, mac or unix
Topic: XNView
Replies: 13
Views: 426

Re: XNView

I had no problem installing XNView, just downloaded the deb, double-clicked it and pressed install. Spritefile sounds promising, I downloaded python imaging library, built, installed, downloaded spritefile, built, installed BUT spr2img.py Screen0.acorn convert.png Traceback (most recent call last):...
by paulb
Mon Oct 23, 2017 9:14 pm
Forum: software & utilities for the pc, mac or unix
Topic: XNView
Replies: 13
Views: 426

Re: XNView

Anyone had experience of using Sprite files in XNView? Or anything else even? I've used davidb's spritefile module which did even provide a GIMP plugin after some messing around I once did, but I'm not sure that the plugin still works. Still, the command line tools probably keep doing the business.
by paulb
Thu Oct 19, 2017 9:08 pm
Forum: hardware
Topic: 128K banked flash ROM cartridge
Replies: 10
Views: 459

Re: 128K banked flash ROM cartridge

Yeah, that's an interesting puzzle. The /FC73 line in the cartridge interface would be much more useful if it only went low for the currently selected cartridge. Exactly. /INFC and /INFD go low when the CPU is accessing &FCxx and &FDxx, so if you want to have your paging register at a diffe...
by paulb
Thu Oct 19, 2017 7:14 pm
Forum: hardware
Topic: 128K banked flash ROM cartridge
Replies: 10
Views: 459

Re: 128K banked flash ROM cartridge

Nice work! First time I've seen anyone using the &FC73 paging register... that'll be interesting to play with! Dave and I discussed other mechanisms for having a slot-specific paging register. Unfortunately (but understandably), the output enable signals are relevant only to accesses within the...
by paulb
Wed Oct 18, 2017 2:29 pm
Forum: software: other
Topic: Acornsoft P-System
Replies: 9
Views: 354

Re: Acornsoft P-System

Obligatory Chris's Acorns link: P-System Acornsoft/TDI (APP14)

It is the UCSD p-System running on the Beeb with 6502 second processor providing Pascal and Fortran compilers and the p-code runtime, of course.
by paulb
Mon Oct 09, 2017 9:03 pm
Forum: software: other
Topic: Turbo Cassette
Replies: 38
Views: 2746

Re: Turbo Cassette

by paulb
Thu Oct 05, 2017 4:55 pm
Forum: off-topic
Topic: Alternate Universe Micros...
Replies: 17
Views: 681

Re: Alternate Universe Micros...

Proton Rev C - BBC Micro Model B+ or B+ with third party shadow RAM extension... Z80 second processor for CP/M. Also Amstrad CPC 6128) One has to wonder what might have happened if Acorn and Amstrad had collaborated at different points in time. Having read "The Amstrad Story", referenced ...
by paulb
Thu Oct 05, 2017 11:01 am
Forum: off-topic
Topic: Alternate Universe Micros...
Replies: 17
Views: 681

Re: Alternate Universe Micros...

The interesting thing about this universe and Acorn's own activities in it is that there are actually plenty of "alternative" microcomputers in Acorn's portfolio. I cannot remember the source for this right now, but an apparent condition connected to offering Acorn the BBC contract based o...
by paulb
Mon Oct 02, 2017 3:59 pm
Forum: general
Topic: Which games from other platforms did you wish was on the BBC?
Replies: 17
Views: 890

Re: Which games from other platforms did you wish was on the BBC?

I always longed for a proper version of Gauntlet, but could never really see how it would look nice on a Beeb, even if it could run at a decent speed. Between jerky scrolling, hi res / no colours, or chunky res with colours, it always seemed like an impossible task. That said, I've since imagined h...
by paulb
Sun Oct 01, 2017 1:04 pm
Forum: hardware
Topic: Electron ULA Schematics
Replies: 21
Views: 1150

Re: Electron ULA Schematics

Thanks to Harry for making these scans available! Page 4/Sheet 5 might be related to the keyboard decoding, just from a quick look. Page 5/Sheet 6 seems to have colour outputs, so it might be related to the palette. Page 6/Sheet 7 might be related to the display logic, given some of the labels. Page...
by paulb
Mon Sep 18, 2017 5:41 pm
Forum: software: classic games
Topic: Galaforce 30th Anniversary Full Source code for BBC Micro
Replies: 15
Views: 1915

Re: Galaforce 30th Anniversary Full Source code for BBC Micro

What is the licence of the work? Does GitHub care about hosting potentially non-redistributable software? (Probably not: it drives people to their platform.) I'm not trying to infringe anyones copyrights and there are plenty of other examples of buildable retro BBC Micro software on github. I'd als...
by paulb
Mon Sep 18, 2017 1:42 pm
Forum: software: classic games
Topic: Galaforce 30th Anniversary Full Source code for BBC Micro
Replies: 15
Views: 1915

Re: Galaforce 30th Anniversary Full Source code for BBC Micro

I've finally managed to push this up to github for anyone interested. https://github.com/crumbgit/Galaforce What is the licence of the work? Does GitHub care about hosting potentially non-redistributable software? (Probably not: it drives people to their platform.) Also, in the README.md file it sa...

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