Search found 226 matches

by ctr
Tue Jun 06, 2017 3:24 pm
Forum: hardware
Topic: OS RAM module
Replies: 84
Views: 6997

Re: OS RAM module

In BASIC2 LOMEM and HIMEM are freely assignable.

Code: Select all

>LOMEM=&C000:HIMEM=&E000
>PRINT~LOMEM,~HIMEM
      C000      E000
I don't know if the rest of BASIC would cope with this.
by ctr
Sat Jun 03, 2017 5:48 pm
Forum: programming
Topic: Break/continue in BASIC loops?
Replies: 20
Views: 1300

Re: Break/continue in BASIC loops?

If you exit a loop with a GOTO then the loop remains active. The terminator of the next loop will actually jump back to the previous still-active loop. An example might be clearer: 10FORI%=1TO20 20PRINT"I ";I% 30PROCLOOP 40NEXT 50END 60DEFPROCLOOP 70FORJ%=1TO6 80PRINT"J ";J% 90IF J%=3GOTO110 100NEXT...
by ctr
Thu Jun 01, 2017 4:54 pm
Forum: programming
Topic: 6502 BASIC Compiler
Replies: 25
Views: 2730

Re: 6502 BASIC Compiler

So if I understand the article correctly the summary is. - compiled code much faster unless float based - Compiler code size much bigger ( ABC has runtime library, riscbasic adds to each program) - restrictions on code, more so with ABC They both support libraries, Like *link on mdfs, but requires ...
by ctr
Thu Jun 01, 2017 2:25 pm
Forum: emulators
Topic: Latest version of BeebEm
Replies: 29
Views: 4792

Re: Latest version of BeebEm

4.15 is close to being released.

jgh's VDFS changes were a last-minute addition and there is still some discussion. (I'm mungre there.)

And Mike Wyatt has just pushed Music 5000 emulation.
by ctr
Fri May 26, 2017 1:57 pm
Forum: software: other
Topic: Exiting the current language?
Replies: 13
Views: 1419

Re: Exiting the current language?

If you use OSHWM upwards then you're destroying the BASIC program, or word-processed document or whatever it is the user was working on. The data left in zero page is an obituary.

At this point there is no reason not to restart BASIC (or whatever) with a clean slate.
by ctr
Tue May 23, 2017 10:12 pm
Forum: software: other
Topic: Exiting the current language?
Replies: 13
Views: 1419

Re: Exiting the current language?

As far as I know there is no way to exit all languages on the BBC B because there is nowhere else to go. (If you start the computer with no language ROM it displays "Language?" and stops. In this situation you can boot from a *RUNnable disk, but that's about it.) This doesn't matter though. If your ...
by ctr
Tue May 23, 2017 3:35 pm
Forum: hardware
Topic: Question about MEMC translation tables reprogramming
Replies: 12
Views: 961

Re: Question about MEMC translation tables reprogramming

Yes, access to physical memory requires supervisor mode. The audio memory is out of the way at 1F06000-1F07FFF.
by ctr
Tue May 23, 2017 2:27 pm
Forum: hardware
Topic: Question about MEMC translation tables reprogramming
Replies: 12
Views: 961

Re: Question about MEMC translation tables reprogramming

The only potential speed up from using physical memory I'm aware of, is to avoid checking for screen overruns by allowing code to write past &1FFFFFF into the physical memory range. This is also useful for hardware scrolling, as the screen is always mapped to physical pages 0 upward, and physical p...
by ctr
Mon May 22, 2017 4:15 pm
Forum: software
Topic: Hacker needed ... for Zarch ;-)
Replies: 161
Views: 17100

Re: Hacker needed ... for Zarch ;-)

tlsa wrote:That screenshot doesn't look like it has dithering enabled to me. Is it the right one?
If you look over the top of the three rockets the furthest background is clearly dithered. If you load the image into a picture editor and zoom it you can see the foreground dithering too.
by ctr
Sun May 21, 2017 6:09 pm
Forum: general
Topic: 8bs.com
Replies: 10
Views: 1292

Re: 8bs.com

cjr8bs commented further down that thread. He said the server was hacked and they intend to fix it.
by ctr
Sun May 21, 2017 12:31 pm
Forum: general
Topic: Today ZAP museum received....
Replies: 52
Views: 4215

Re: Today ZAP museum received....

Phone calls were expensive. If the phone was placed conveniently there was a real danger of it being used.
by ctr
Thu May 18, 2017 3:30 pm
Forum: emulators
Topic: b2 - new emulator
Replies: 114
Views: 11048

Re: b2 - new emulator

Does it look the same with UI filtering on and with it off? (It's supposed to, and it does on my laptop at least.) If the UI filtering option is now redundant, I'll get rid of it... Four snapshots of the basic prompt with the filter dialog and messages window visible. I restarted the emulator befor...
by ctr
Thu May 18, 2017 1:02 am
Forum: emulators
Topic: b2 - new emulator
Replies: 114
Views: 11048

Re: b2 - new emulator

(As for whether there are further problems, I don't think so, but there's no shortage of evidence that I could be mistaken ;) The other SDL functions look to add the -0.5 offset in for you, so they should be fine as they are. But SDL_RenderGeometry just passes your vertex data straight through.) I ...
by ctr
Wed May 17, 2017 2:43 pm
Forum: emulators
Topic: b2 - new emulator
Replies: 114
Views: 11048

Re: b2 - new emulator

Yes, d3d11 has half pixel offsets by default, while d3d9 doesn't. Could explain the differences in various machines. Ah! The obvious explanation didn't occur to me. Maybe I'm the only person using the d3d9 rendering and it's just broken. If this is the case then a fix would be to add the offset in ...
by ctr
Wed May 17, 2017 1:30 am
Forum: emulators
Topic: b2 - new emulator
Replies: 114
Views: 11048

Re: b2 - new emulator

I tried d3d11. The good news is that I get the same results with and without the half pixel offset. The bad news is that it's comically broken on this ancient GPU. I tried the half-pixel text offset in a previous post. It has clear text but fuzzy menus as you'd expect. I'm really puzzled by this off...
by ctr
Tue May 16, 2017 10:31 pm
Forum: emulators
Topic: b2 - new emulator
Replies: 114
Views: 11048

Re: b2 - new emulator

I realised that it wasn't just the text but everything in the GUI that had the offset problem. I turned off the filtering and the text offset and hacked SDL's world transformation to move everything by half a pixel: diff --git a/src/render/direct3d/SDL_render_d3d.c b/src/render/direct3d/SDL_render_d...
by ctr
Tue May 16, 2017 3:14 pm
Forum: emulators
Topic: b2 - new emulator
Replies: 114
Views: 11048

Re: b2 - new emulator

I tried commit 1f8c690 which sets a text rendering offset. The text looks great! It is much better than the linear filter.
by ctr
Tue May 16, 2017 1:13 am
Forum: emulators
Topic: b2 - new emulator
Replies: 114
Views: 11048

Re: b2 - new emulator

I edited my previous comment while you were posting. The "linear" filter is an improvement.
by ctr
Tue May 16, 2017 12:36 am
Forum: emulators
Topic: b2 - new emulator
Replies: 114
Views: 11048

Re: b2 - new emulator

I built it on Windows with cmake 3.8.1. gen_6502.py failed because I've got python3. I replaced all the .iteritems() with .items() and that fixed it. You need to add python2 to the instructions as a prerequisite. I need to read the instructions. Building open source projects with lots of dependencie...
by ctr
Mon May 15, 2017 10:55 pm
Forum: emulators
Topic: b2 - new emulator
Replies: 114
Views: 11048

Re: b2 - new emulator

It's possible that a compiled language which supported coroutines as a native language feature might offer the best way to approach emulator code like this (as essentially what you have is a whole bunch of components running simultaneously), but I'm not aware of such a language (and coroutine libra...
by ctr
Mon May 15, 2017 8:46 pm
Forum: development tools
Topic: Request membership of the Stardot organisation on GitHub here
Replies: 58
Views: 7905

Re: Request membership of the Stardot organisation on GitHub here

Please add mungre on github. Thank you.
by ctr
Mon May 15, 2017 7:09 pm
Forum: emulators
Topic: b2 - new emulator
Replies: 114
Views: 11048

Re: b2 - new emulator

If I shrink the window the beeb text also gets all lumpy. There is no anti-aliasing going on. Please could you go to Tools|Messages, click Copy, and paste the output here? Renderer: direct3d, 736x576 SDL_PIXELFORMAT_ARGB8888 Sound: directsound, 48000Hz 1-channel (4096 byte buffer) Also what sort of ...
by ctr
Mon May 15, 2017 4:17 pm
Forum: emulators
Topic: b2 - new emulator
Replies: 114
Views: 11048

Re: b2 - new emulator

This makes such a realistic - and horrible - disc drive noise I thought something had gone wrong my laptop. Then I remembered I don't have a floppy drive! The timeline and clone features are really nice. I had thought of adding a state recorder to beebem but I needn't bother now. Is it possible to s...
by ctr
Mon May 08, 2017 3:12 pm
Forum: hardware
Topic: Palettemate / enhanced video ULA with 4096 colours
Replies: 595
Views: 54819

Re: Palettemate / enhanced video ULA with 4096 colours

And yes, if you read my post, I do say that there is sync circuitry. This drops the video signal to a lower level for the sync pulses. But it is simply a resistor that connects to a logic gate. There is no circuitry to enforce a set level. The sync circuit simply mixes the sync into the video signa...
by ctr
Mon May 08, 2017 12:19 am
Forum: hardware
Topic: Palettemate / enhanced video ULA with 4096 colours
Replies: 595
Views: 54819

Re: Palettemate / enhanced video ULA with 4096 colours

So my conclusion is, either the machine does not generate a "super black" level (it just uses the black border), or it is all done in the ULA. In composite video the sync pulses are periods of super-black so the beeb must generate them or TVs would lose sync when displaying a black screen. Page 497...
by ctr
Fri May 05, 2017 8:07 pm
Forum: software & utilities for the pc, mac or unix
Topic: Writing to an ADFS partition in Linux
Replies: 9
Views: 2165

Re: Writing to an ADFS partition in Linux

This week I found an alternative approach that may help others. Using the linux dd command I made an image of an IDE drive and found that I could open and write directly to the image using Arculator by simply renaming it to "HD4.HDF". If you mount the IDE drive at a directory called "HD4.HDF" would...
by ctr
Fri May 05, 2017 3:02 pm
Forum: hardware
Topic: Fake, too slow, of just defective?
Replies: 20
Views: 1700

Re: Fake, too slow, of just defective?

Coeus wrote:Thanks for a very useful tool - I first used this to validate CPU emulation fixes in B-Em but it has been just the job here as well.
I'm glad it helps. The "6502 detected" message means the CPU has the indirect jump bug, which is characteristic of NMOS versions.
by ctr
Fri May 05, 2017 11:34 am
Forum: hardware
Topic: Fake, too slow, of just defective?
Replies: 20
Views: 1700

Re: Fake, too slow, of just defective?

This seemed to work reliably, at least for the testing so I was able to load tricky's menu-driven CPU test (which actually runs the Dorman tests, I believe) It's not tricky's it's mine! It does run Klaus Dormann's 6502 test with a couple of additions, and also Bruce Clark's BCD test. There is a mor...
by ctr
Sun Apr 30, 2017 11:26 am
Forum: software: new games
Topic: New Release: Castle Defender
Replies: 32
Views: 7201

Re: New Release: Castle Defender

This new version is a real challenge. Recommended!
by ctr
Thu Apr 27, 2017 11:12 pm
Forum: off-topic
Topic: Why are domino plugs reversible?
Replies: 4
Views: 1019

Re: Why are domino plugs reversible?

If Acorn had wired the socket with RTS diagonally opposite CTS and RX diagonally opposite TX then you could have used the same cable as both a modem cable and null-modem cable by rotating the connector 180°. I think. But they didn't. I always wondered if that was the point of the symmetrical connect...