Search found 2161 matches

by sweh
Thu May 28, 2020 12:55 am
Forum: programming
Topic: Incrementing a 2-byte number
Replies: 14
Views: 393

Re: Incrementing a 2-byte number

You should see the work MartinB originally did for UPURS and then Dave (hoglet)'s updates. To bit-bang the User Port at 115,200 baud you only have 8.68us per bit, on average! And part of that is spent at 1Mhz 'cos of slow-bus access... Amazing work by both of them!
by sweh
Sun May 17, 2020 4:34 pm
Forum: 8-bit acorn software: other
Topic: Writing a service rom - it's not recognized
Replies: 14
Views: 388

Re: Writing a service rom - it's not recognized

Yes, this seems to be the cause. When I disable DFS in BeebEm then I get my message displayed. But this is not according the text in the advanced user guide: It's not written clearly, but it is the expected behaviour. "To allow lower priority services...initialise only if ... no key is pressed" is ...
by sweh
Sun May 17, 2020 3:28 pm
Forum: 8-bit acorn hardware
Topic: All the cheese wedges, in order
Replies: 19
Views: 649

Re: All the cheese wedges, in order

hoglet wrote:
Sun May 17, 2020 2:59 pm
Actually, I think I have one :shock:
Funny; the board says 16032 but the CPU says 32016; according to wikipedia NS renamed the chip :-) https://en.wikipedia.org/wiki/NS320xx#32016
by sweh
Sun May 17, 2020 2:15 pm
Forum: 8-bit acorn software: other
Topic: Writing a service rom - it's not recognized
Replies: 14
Views: 388

Re: Writing a service rom - it's not recognized

If no key is pressed while doing a BREAK then the highest priority filesystem (DFS, ADFS) will likely have intercepted the call, done it's setup then set A=0. After all, only one file system should be able to autoboot. If you want to do hardware initialization on every BREAK then I've found using se...
by sweh
Sun May 17, 2020 1:53 am
Forum: 8-bit acorn software: other
Topic: Writing a service rom - it's not recognized
Replies: 14
Views: 388

Re: Writing a service rom - it's not recognized

EQUB &00:EQUS "X.YZ" or EQUB &00:EQUS "X.YZ (dd MMM YYYY)" This isn't really so well defined. There are plenty of ROMs BITD that don't follow anything like this. EQUS "YYYY Author" if you don't have the date in the version string ("YYYY ...." not " YYYY.....") EQUS "Author" if you do have the date ...
by sweh
Sat May 16, 2020 10:23 pm
Forum: 8-bit acorn software: other
Topic: Writing a service rom - it's not recognized
Replies: 14
Views: 388

Re: Writing a service rom - it's not recognized

equs "(c) 2020 Roland Leurs"
Making a wild guess; shouldn't that be a capital C in "(C)" and not a lower case "(c)" ?

You can see if the ROM has been detected as a valid ROM by looking in ?(&2A1+slot)... at least on a Beeb, and I think the Elk uses the same location!
by sweh
Mon May 11, 2020 2:26 am
Forum: 32-bit acorn software: other
Topic: Shredding free space of hard drives
Replies: 13
Views: 413

Re: Shredding free space of hard drives

If you can plug them into a Linux machine then https://wiki.archlinux.org/index.php/Securely_wipe_disk may give some ideas.

If Windows then DBAN ( https://dban.org/ ) may help.
by sweh
Sat May 09, 2020 2:00 am
Forum: programming
Topic: In-game music
Replies: 17
Views: 656

Re: In-game music

SteveF wrote:
Sat May 09, 2020 1:48 am
It looks like it *should* be *TOCCATA too, but that didn't work for me. Could there be a missing 0 byte at the end of .title in L.TOCCATA?! (It does work if I do e.g. "*TOC.")
Very probably, yes :-) I haven't looked at this code in decades!
by sweh
Fri May 08, 2020 11:42 pm
Forum: for sale / freebies
Topic: BBC Master ANFS Chip
Replies: 4
Views: 233

Re: BBC Master ANFS Chip

jgharston wrote:
Fri May 08, 2020 10:40 pm
It reads prefectly ok, on startup it tests to see if it's on a Master and if not stops with an error, as the hardware isn't where it needs it to be.
Yeah, you get the same result if you have the ROM in a Master with a switching OS (3.5/3.2/1.2). In 1.2 mode you get the Bad ROM error.
by sweh
Fri May 08, 2020 11:39 pm
Forum: programming
Topic: In-game music
Replies: 17
Views: 656

Re: In-game music

BITD I converted a few tunes into an interrupt driven ROM services (via USERV). And when one ROM finished playing it'd automatically call the next one in sequence. I stole the tunes from various places and then mangled it up. Hmm.... Ah, here we are! The "L." files are the programs that created the ...
by sweh
Thu May 07, 2020 8:38 pm
Forum: 8-bit acorn emulators
Topic: Is there a Windows command line tool to make SSD images?
Replies: 4
Views: 204

Re: Is there a Windows command line tool to make SSD images?

If you install perl on your Windows machine, my tools _should_ work... https://sweh.spuddy.org/Beeb/mmb_utils.html
by sweh
Thu May 07, 2020 1:10 am
Forum: the complete BBC games archive
Topic: Games with problems
Replies: 93
Views: 6456

Re: Games with problems

160*LOAD HELL1 170*TAPE 180CALL&4A72 which probably then makes the BASIC ROM the default ROM fixing the problem mentioned by Sarah. You probably don't need *TAPE because BASIC will already be paged back in to run the CALL command. Unless the program makes a filesystem call before reading &8000... A...
by sweh
Thu May 07, 2020 1:09 am
Forum: the complete BBC games archive
Topic: Games with problems
Replies: 93
Views: 6456

Re: Games with problems

Looks to be a bug with the random number generator. Hell-Hole is using $8000-$8002 as a seed, which obviously depends on the current selected sideways ROM. On at least both DFS 0.9 and 1770 DFS 2.26 $8000-$8002 are all zero, which causes the generator to always return $ff, which causes the game to ...
by sweh
Wed May 06, 2020 3:45 am
Forum: 8-bit acorn software: other
Topic: When did BASIC II become current?
Replies: 3
Views: 279

Re: When did BASIC II become current?

I've never owned a machine with BASIC I, but a lot of my earlier code had a "DEF PROCoscli" procedure (store the string in memory, set X% Y%, CALL OSCLI) because I wanted it to work on older machines. So the question isn't when BASIC II became current, but when we decided to stop supporting BASIC I....
by sweh
Sun May 03, 2020 1:49 pm
Forum: programming
Topic: Utilising pages &600-&700
Replies: 4
Views: 255

Re: Utilising pages &600-&700

If you're never going to drop back into BASIC (or call functions in the BASIC ROM) then you can use pages 4->7 completely.
by sweh
Thu Apr 30, 2020 6:46 pm
Forum: programming
Topic: Stack question
Replies: 7
Views: 245

Re: Stack question

The DEY at line 480 is wrong and shouldn't be there. You're returning a byte too early and re-running some of the code. Edit: 0x0d is "ORA abs" the RTS is being used as part of the address to the ORA instruction and that allows it to drop back into the "STA &70" code and so corrupt what you're looki...
by sweh
Thu Apr 30, 2020 5:40 pm
Forum: 8-bit acorn hardware
Topic: Watford Epson NLQ ROM
Replies: 4
Views: 173

Re: Watford Epson NLQ ROM

Thanks; I'll update my bookmarks :-)
by sweh
Thu Apr 30, 2020 4:51 pm
Forum: 8-bit acorn hardware
Topic: Watford Epson NLQ ROM
Replies: 4
Views: 173

Re: Watford Epson NLQ ROM

I found this from the old nvg.ntnu.no site (which seems to have gone)
by sweh
Tue Apr 28, 2020 12:35 am
Forum: 32-bit acorn hardware
Topic: 35 Years yesterday?
Replies: 2
Views: 264

Re: 35 Years yesterday?

I had tweeted about it:

"And now ARM based processors have taken over the world. There are rumours that the nextgen Apple _desktops_ will be ARM based!

Shame Acorn, the company, died. But at least they have a legacy in the Acorn RISC Machine :-)"
by sweh
Sun Apr 26, 2020 8:01 pm
Forum: programming
Topic: Halving mode screen memory
Replies: 5
Views: 280

Re: Halving mode screen memory

Could anybody please point me towards information on halving the screen memory? Specifically reducing y pixels e.g. mode 1 256 to 128 Does this then shift memory from &3000 upwards? Also do i need to centre the resulting display? Check out the "MODE 8" demonstration from the Advanced User Guide ( h...
by sweh
Sun Apr 19, 2020 3:40 pm
Forum: 8-bit acorn software: other
Topic: DFS floppy capacity and dsd format
Replies: 15
Views: 449

Re: DFS floppy capacity and dsd format

Yes, I am guessing Acorn considered compatibility of the discs more important than the extra capacity, though there was the 40/80 track problem too. To be fair to them, with only 31 catalogue entries, it was common to run out of filenames before you ran out of space even in single-density. This is ...
by sweh
Sun Apr 19, 2020 2:27 am
Forum: 8-bit acorn software: other
Topic: DFS floppy capacity and dsd format
Replies: 15
Views: 449

Re: DFS floppy capacity and dsd format

Are there any utilities for transferring files from a PC onto a floppy image? If you're talking about read/write from a real 5.25" floppy then the problem is that most PCs can't read/write single density 5.25" disks. Some old machines might be able to, but... So one of the simple solutions is to cr...
by sweh
Sun Apr 19, 2020 2:17 am
Forum: 8-bit acorn hardware
Topic: What printer are you still using?
Replies: 14
Views: 442

Re: What printer are you still using?

Back in the day I had a Centronics GLP with both roll-feed and tractor feed. It worked well, but I didn't bring it to America with me.

Today I have an Espon MX80, but I haven't printed anything on it for so long that I suspect the ribbon has dried out!
by sweh
Sun Apr 19, 2020 2:10 am
Forum: 8-bit acorn software: other
Topic: DFS floppy capacity and dsd format
Replies: 15
Views: 449

Re: DFS floppy capacity and dsd format

So double sided double density would be 800k total space? "Double density" didn't double the amount of storage. You either got 16 or 18 sectors per track, depending, resulting in 640K or 720K. Soldisk DDFS was 640K and showed as 320K drive 0, 320K drive 2. Opus DDOS was 720K, but they "sub-partitio...
by sweh
Sun Apr 19, 2020 1:56 am
Forum: 8-bit acorn software: other
Topic: DFS floppy capacity and dsd format
Replies: 15
Views: 449

Re: DFS floppy capacity and dsd format

An SSD image is a 200K "single sided disk" image. (80 tracks, 10 sectors per track, 256bytes per track). "Single Sided Single Density" from back in the old days. A DSD file is treated as a double sided disk and so provides *DRIVE 0 and *DRIVE 2 (side a and b) of a floppy. "Double Sided Single Densit...
by sweh
Sat Apr 18, 2020 12:42 pm
Forum: programming
Topic: Does BBC BASIC short circuit IF statements?
Replies: 22
Views: 728

Re: Does BBC BASIC short circuit IF statements?

So I did a simple test:

Code: Select all

10 DEF FNA:PRINT "IN A":=1
20 DEF FNB:PRINT "IN B:=1
30 IF FNA AND FNB THEN PRINT "TRUE"
Now run that and you'll get

Code: Select all

IN A
IN B
TRUE
We now change line 10 to =0 instead and run it

Code: Select all

IN A
IN B
So we can see that FNB is still called even though FNA returns FALSE.
by sweh
Fri Apr 17, 2020 2:20 am
Forum: introduce yourself
Topic: Hi from the South Coast
Replies: 10
Views: 341

Re: Hi from the South Coast

if anyone knows the magic to make flash floppy present an image that ddfs can format in double density that would be epic :) The standard MMC (Userport) solutions won't be detected by DDFS. These require alternate ROMs, such as MMFS. Neither will those that work off the 1Mhz bus. Basically you need...
by sweh
Tue Apr 14, 2020 1:09 pm
Forum: programming
Topic: Which OS calls can be used inside which event/vector handlers on the BBC/Electron/Master?
Replies: 4
Views: 368

Re: Which OS calls can be used inside which event/vector handlers on the BBC/Electron/Master?

Is there a list/table anywhere? I have a comment in some of my code saying that OSWORD can be called from an event handler, but I can't find this written down anywhere "official" now, and I'm failing to find the magic keywords to locate this information in any of the usual references. A couple of r...
by sweh
Thu Apr 09, 2020 7:55 pm
Forum: archive submissions
Topic: 30th Anniversary BBC and Electron Collection
Replies: 601
Views: 95801

Re: 30th Anniversary BBC and Electron Collection

That's really neat would you mind sharing the script maybe put a Gist on GitHub or something? It's part of a set of tools I put together for leenew to help him extract SSDs for testing and for the bbcmicro site. It lives at https://github.com/sweharris/split_md_dsd It's only 70 lines of shell scrip...
by sweh
Thu Apr 09, 2020 7:05 pm
Forum: archive submissions
Topic: 30th Anniversary BBC and Electron Collection
Replies: 601
Views: 95801

Re: 30th Anniversary BBC and Electron Collection

Hi, I'm afraid at the moment they have to be downloaded from here one at a time. FWIW, I wrote a small program to "Screen scrape" and find all the zip files and downoad them. This zip file is "up to date" as of 2020/04/09 18:00 GMT :-) Of course it'll be out of date as Michael finds and fixes older...

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