Search found 179 matches

by joachim
Sun Sep 06, 2020 1:07 pm
Forum: general
Topic: BBC Micro Books
Replies: 9
Views: 720

Re: BBC Micro Books

The trouble is most books of type-in listings were published in the early '80s before the limits of the machine were well explored, and most later, better type-in games were in magazines. If you like the style of text-only minicomputer games converted to BASIC, the most sophisticated are the books b...
by joachim
Thu Aug 13, 2020 1:28 pm
Forum: 32-bit acorn software: other
Topic: Bug in RISC OS Time/Date?
Replies: 7
Views: 515

Re: Bug in RISC OS Time/Date?

I did try *CONFIGURE NODST but it didn't help. It still doesn't explain why it adds a whole 24 hours between midnight and 1am, that's some British Summer Time!! (Actually that is the average length of a British summer, spread over about 7 years). A timezone-related bug would cause exactly the effec...
by joachim
Tue Aug 11, 2020 8:07 am
Forum: archive submissions
Topic: Inspiring Software - Four games for the BBC Micro
Replies: 5
Views: 464

Re: Inspiring Software - Four games for the BBC Micro

Here you go, Acorn User May 1990 p126: https://archive.org/details/AcornUser094-May90/page/n127/mode/2up Possibly this is the exact source of the "Missing Games" entry, since it has the "Inspring" misspelling and the "c" of "Mancala" is very badly printed. 75p each, except that you have to phone an ...
by joachim
Mon Aug 10, 2020 9:13 pm
Forum: archive submissions
Topic: Inspiring Software - Four games for the BBC Micro
Replies: 5
Views: 464

Re: Inspiring Software - Four games for the BBC Micro

It looks as if Birdies and Mancala are on the "Missing BBC Games" list (https://stardot.org.uk/forums/viewtopic.php?t=14458), although Mancala is misspelt there as "Manoala", and Inspiring is misspelt as "Inspring". I suppose it's too much to hope that "Zarlix", the other Inspring game on that list,...
by joachim
Sun Aug 09, 2020 9:13 pm
Forum: 8-bit acorn software: classic games
Topic: Spycat variant
Replies: 38
Views: 2082

Re: Spycat variant

That one's really interesting actually -- the monochrome masks that are obviously used to mask the sprite off from the background. I wonder how common that was. Citadel just sidestepped this problem with its signature XOR plotting. As did Palace of Magic and Quest, and even Citadel 2 as late as 199...
by joachim
Sun Aug 09, 2020 3:51 pm
Forum: 8-bit acorn software: classic games
Topic: Spycat variant
Replies: 38
Views: 2082

Re: Spycat variant

This thread inspired me to play through Spycat and I discovered another very similar walk-through bug (?). From the final location at Heathrow http://www.stairwaytohell.com/gamehelp/MAP-SpyCat-BC/HEATHx2.png you can again jump up to the top right corner and walk right. You come out in Greenland, but...
by joachim
Fri Jul 31, 2020 4:08 am
Forum: the complete BBC games archive
Topic: dfscat bug fixed
Replies: 5
Views: 894

Re: dfscat bug fixed

Thanks Richard. At a glance it looks as if that code is doing a few light checks to see whether sectors &A and &B look like a valid DFS catalogue, which they would need to be if it's a .dsd image and they are the sectors &0 and &1 of side 2. But it's only checking whether the disc title is made of p...
by joachim
Wed Jul 29, 2020 8:06 pm
Forum: the complete BBC games archive
Topic: dfscat bug fixed
Replies: 5
Views: 894

Re: dfscat bug fixed

I'm still seeing an issue similar to this. If you go to Boxer (http://bbcmicro.co.uk/explore.php?id=148) and view the hex dump of $.BOX, you can see the dump of the game instructions but they appear to cut off suddenly at &0700 after the text "Every time you get three falls" and are followed by garb...
by joachim
Sun Jul 26, 2020 8:44 am
Forum: 8-bit acorn software: classic games
Topic: Trying to locate old game "Caves"
Replies: 8
Views: 1502

Re: Trying to locate old game "Caves"

Thanks guys; it's not either of those. It's a top-down view and the tiles and ball are much smaller. It has some similarities to Sphere of Destiny but the ball is constantly bouncing every 4 ticks or so, speeding up to every 2 ticks or so if you land on a particular type of tile, slowing back down ...
by joachim
Sat Jul 25, 2020 6:11 pm
Forum: 8-bit acorn software: other
Topic: How far do BASIC line numbers go?
Replies: 9
Views: 715

Re: How far do BASIC line numbers go?

One more strange aspect of RENUMBER I've discovered: if you try to renumber the program 12000 GOTO 12345 13000 END it takes about half a second on jsbeeb. (There is a "Failed at 10" message too, of course.) Whereas renumbering another similar program, such as 12000 GOTO 12345 12100 END completes ins...
by joachim
Thu Jul 23, 2020 5:30 pm
Forum: 8-bit acorn software: other
Topic: How far do BASIC line numbers go?
Replies: 9
Views: 715

Re: How far do BASIC line numbers go?

cmorley wrote:
Thu Jul 23, 2020 8:58 am
Line numbers on 8-bit BBC BASICs are 15bit integers so 0-32767

Try the following and start entering a program...

Code: Select all

AUTO32767,1
Okay, this gave me a slightly more evil idea. Try making a program of, say, ten lines, and then RENUMBER 32767,1 ...
by joachim
Sat Jun 20, 2020 9:37 pm
Forum: 32-bit acorn software: other
Topic: Acorn Virus in the early 90’s
Replies: 7
Views: 878

Re: Acorn Virus in the early 90’s

According to the Archimedes Virus Reference Document (http://www.bogus.net/~torh/files/AVRD-1.91t.txt, other copies also findable on Google), you're most likely referring to a virus called "Module" or "ModVir": Module =========================================================================== Last U...
by joachim
Thu Jun 18, 2020 2:27 pm
Forum: other vintage hardware, software and languages
Topic: Papercraft models of 80s computers
Replies: 6
Views: 1012

Re: Papercraft models of 80s computers

Interesting that the Repton 2 screenshot is of the early/prerelease edition in which Screen A is red rather than blue. (Repton 2 colours thread)
by joachim
Wed Jun 10, 2020 10:59 pm
Forum: scanning of books, magazines, ads and letters
Topic: Personal Computer World scans!
Replies: 61
Views: 4018

Re: Personal Computer World scans!

Out of interest, which is the earliest PCW magazine to feature the BBC Micro ? That would be December 1981: https://archive.org/details/PersonalComputerWorld1981-12/mode/2up Seriously, though, I'd hang about until they've all finished deriving the "PDF with Text" versions. The initial PDFs are gian...
by joachim
Tue Jun 09, 2020 9:51 am
Forum: 8-bit acorn software: classic games
Topic: Dunjunz reminiscing and walkthrough
Replies: 8
Views: 1132

Re: Dunjunz reminiscing and walkthrough

What would it take to get the new levels hosted on bbcmicro.co.uk?
by joachim
Mon Jun 01, 2020 3:47 pm
Forum: programming
Topic: Reducing Basic Program Size
Replies: 42
Views: 3096

Re: Reducing Basic Program Size

One way programs can use space unnecessarily is having two copies of things in memory: one copy in a program statement defining it, and another copy in its intended location in memory. As you mentioned, the classic example is DATA statements - the data exists twice, in the DATA statements themselve...
by joachim
Sun May 31, 2020 12:32 pm
Forum: programming
Topic: Adding in negative numbers
Replies: 12
Views: 675

Re: Adding in negative numbers

LDA&81 ; bytes 2 cycles 3 TAX; CLC ; bytes 1 cycles 2 ADC&86 bytes 2 cycles 3 STA&81 ; bytes 2 cycles 3 BCC done ; bytes 2 cycle 2/3 TXA BMI dechighbyte INC &82; bytes 2 cycles 5 BNE done .dechighbyte DEC &82 ; bytes 2 cycles 5 .done In the negative-offset case, that code DECs when the carry is set...
by joachim
Sun May 31, 2020 9:09 am
Forum: programming
Topic: Adding in negative numbers
Replies: 12
Views: 675

Re: Adding in negative numbers

I found code examples here: https://codebase64.org/doku.php?id=base:signed_8bit_16bit_addition It seems you cannot do better than to calculate the high byte and ADC it. (The alternative would be to have a branch with INC and a branch with DEC and to determine explicitly which of four cases you're in...
by joachim
Sat May 30, 2020 4:58 pm
Forum: 8-bit acorn software: classic games
Topic: Dunjunz reminiscing and walkthrough
Replies: 8
Views: 1132

Re: Dunjunz reminiscing and walkthrough

Recently? Your playthroughs inspired this interesting forum thread back in 2016!
by joachim
Wed May 27, 2020 7:49 pm
Forum: scanning of books, magazines, ads and letters
Topic: Personal Computer World scans!
Replies: 61
Views: 4018

Re: Personal Computer World scans!

I believe there are quite a few Acorn program listings in PCW that have yet to be archived (see for example https://ukfree.tv/documents/pcw/#Programs).
by joachim
Thu Apr 30, 2020 10:56 am
Forum: 8-bit acorn software: classic games
Topic: Repton 3: Emulator/RNG issue
Replies: 99
Views: 7026

Re: Repton 3: Emulator/RNG issue

&2F01/&2F01: LDA &31A0,X / LDA #&C sequence replaced with CPY #&A0 / AND (&A9),Y / ASL A; purpose unknown ^^ took another look at this, and decided it was probably data and not code; certainly "JSR &A25C" just above it makes very little sense Looks as if you decompiled with the wrong frame. JSR &A2...
by joachim
Wed Oct 09, 2019 11:04 pm
Forum: 8-bit acorn software: classic games
Topic: Firebug, Sorcery, Boxer and Smash and Grab...
Replies: 6
Views: 782

Re: Firebug, Sorcery, Boxer and Smash and Grab...

More likely that it's just the same basic engine recycled for each game. Other examples of this include Rally Driver / Slippery Sam by Anthony Houghton, Southern Belle / Evening Star by Male and Hillyer, and on the Sinclair QL, Metropolis / Citadel by Janko Mršić-Flögel. Plus of course the explicit...
by joachim
Thu Sep 26, 2019 9:15 pm
Forum: 8-bit acorn hardware
Topic: Problems booting beeb issue 4
Replies: 73
Views: 11525

Re: Problems booting beeb issue 4

In summary, there's no smoking gun here. On the software side, the VARTOP value you obtained matches what my working machine gives. The question is what values is your machine checking against VARTOP... You would expect MODEs 4 and 5 to fail in a 16k machine with DFS (which is the configuration in ...
by joachim
Sun Jul 07, 2019 6:40 pm
Forum: 8-bit acorn software: other
Topic: Basic BASIC Question
Replies: 28
Views: 1960

Re: Basic BASIC Question

And for some reason, people seemed to mostly use 224-255 to refer to them... I investigated this a while ago. The User Guide recommends use of the range 224–225 in chapters 29 and 34, and presumably most people's practices ultimately derive from that. Also, on OS 0.10 , 224–255 are the values retur...
by joachim
Tue Jun 04, 2019 3:59 pm
Forum: 8-bit acorn software: classic games
Topic: Acorn Electron Games that don't work with a plus 1 ?
Replies: 11
Views: 1346

Re: Acorn Electron Games that don't work with a plus 1 ?

Line 30 looks a bit suspicious. I think it should read something like:

30 !&80=USR&FFF4:A%=!&81:A%?12=0
by joachim
Wed Apr 24, 2019 8:36 pm
Forum: 8-bit acorn software: other
Topic: Drawing a circle in BBC BASIC
Replies: 71
Views: 8174

Re: Drawing a circle in BBC BASIC

Logically, if anybody implemented ellipse arcs, sectors, and segments, those are the plot numbers that should be used. Interesting. Have you given any thought to how elliptical arcs, sectors and segments would be specified using only three points (I presume it's a fundamental characteristic of VDU ...
by joachim
Mon Apr 15, 2019 11:21 pm
Forum: other vintage hardware, software and languages
Topic: Interesting treasures in shops near you?
Replies: 3
Views: 745

Re: Interesting treasures in shops near you?

Well, there's a couple of classic machines in this window: https://goo.gl/maps/LjgQ6qSTiy42. Is that the sort of thing you had in mind?
by joachim
Wed Feb 27, 2019 9:35 pm
Forum: archive requests
Topic: The Micro User 1991/1992; Let's Compute Game articles..
Replies: 4
Views: 716

Re: The Micro User 1991/1992; Let's Compute Game articles..

I dumped all the Electron user cassettes back in 2001/2003: http://www.stairwaytohell.com/electron/uefarchive/magtapes/ElectronUser/ Though Mick, Lee and team may well have already gone through these already ... I asked about the (lack of) Electron User games on bbcmicro.co.uk just over a year ago:...
by joachim
Fri Feb 22, 2019 8:46 pm
Forum: for sale / freebies
Topic: Free to collector Archimedes swag
Replies: 26
Views: 3276

Re: Free to collector

Agreed those are 128kB roms. The type numbers (531000, 831000, 231024) end in "1000" or "1024" most likely signifying 1Mbit = 128kB, and Google search for those numbers and "rom" appears to confirm that. (Also, here are some people talking about dumping similar 128kB roms using an EPROM programmer: ...

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