Search found 4257 matches

by jgharston
Tue Jan 26, 2021 9:55 am
Forum: acorn atom and acorn system series
Topic: Acorn System/Atom Econet
Replies: 27
Views: 1964

Re: Acorn System/Atom Econet

Edit: Ah, you have some extra registers. So, a quick change to CPY #&E0 should fix it. I'll check when I get home. Thanks, but I think there's a bit more to it, as you have some active code in FEE0-FEEF. I've moved a table, and renamed the files to be a bit tidier: http://mdfs.net/Software/Tube...
by jgharston
Mon Jan 25, 2021 2:28 pm
Forum: acorn atom and acorn system series
Topic: Acorn System/Atom Econet
Replies: 27
Views: 1964

Re: Acorn System/Atom Econet

When the AtomTube Kernel resets, there is a copy from ROM into RAM (at the same address), and it's this copy that ends up writing random values to the bank select registers at &FEE0-&FEE7, causing the system to crash. Jonathan, any chance you could save a few bytes, and avoid using the &...
by jgharston
Sun Jan 24, 2021 7:47 pm
Forum: general
Topic: Shift Lock Led
Replies: 8
Views: 259

Re: Shift Lock Led

tricky wrote:
Sun Jan 24, 2021 6:28 pm
I think that you can do escape too.
*FX219,27

In the RISC OS desktop TAB is programmed with *FX219,138 to be function key 10 to be independent of Ctrl-I. The buffer entry values are programmed to be &X0+key with *FX221-228 so all keys return their low level keypress code.
by jgharston
Sun Jan 24, 2021 7:38 pm
Forum: acorn atom and acorn system series
Topic: Acorn System/Atom Econet
Replies: 27
Views: 1964

Re: Acorn System/Atom Econet

BeebMaster wrote:
Sun Jan 24, 2021 7:00 pm
Shame there isn't a System emulator for the BBC micro. Or is there?
There's a shim for 6502 CoProcessors or emulators that provides the System/Atom API at &FFxx:
http://mdfs.net/Software/Tube/6502/Atom/
by jgharston
Sun Jan 24, 2021 7:34 pm
Forum: general
Topic: Mode 7 teleetxt graphics question
Replies: 15
Views: 260

Re: Mode 7 teleetxt graphics question

guesser wrote:
Sun Jan 24, 2021 6:09 pm
There isn't really a convenient way to save a block of RAM at a given address from beebem that I'm aware of. I think you can also save stuff out from the debugger by typing the appropriate cryptic commands.
*SAVE
by jgharston
Mon Jan 18, 2021 7:39 pm
Forum: programming
Topic: Mode 7 text windows
Replies: 4
Views: 174

Re: Mode 7 text windows

MODE 7 or not is irrelavant. You can do something like this, dreging up some code from memory: DEFPROCw_init DIM w%(1,5) w%(0,0)=0:w%(0,1)=12:w%(0,2)=39:w%(0,3)=0:w%(0,4)=0:w%(0,5)=0 w%(1,0)=0:w%(1,1)=24:w%(1,2)=39:w%(1,3)=13:w%(1,4)=0:w%(1,5)=0 w_this%=0 ENDPROC : DEFPROCw_select(win%) w%(w_this%,4...
by jgharston
Mon Jan 18, 2021 11:08 am
Forum: programming
Topic: BBC BASIC detecting if it is being run on a BBC or Archimedes
Replies: 14
Views: 312

Re: BBC BASIC detecting if it is being run on a BBC or Archimedes

The closest way to do that is to attempt to assemble a NOP. That gives different opcodes on different CPUs. Ah, but that's testing the assembler not the CPU ! You may say that's a silly remark because the assembler will invariably be the right one for the CPU on which it's running, but that's not a...
by jgharston
Sun Jan 17, 2021 10:56 pm
Forum: programming
Topic: BBC BASIC detecting if it is being run on a BBC or Archimedes
Replies: 14
Views: 312

Re: BBC BASIC detecting if it is being run on a BBC or Archimedes

These are all boring ways! It would be much more interesting to find out whether the processor is a 6502 or an ARM by storing some code directly into memory with !, then running USR on it; the code being carefully chosen to be readable as either 6502 or ARM code, but give different results in each ...
by jgharston
Sun Jan 17, 2021 10:33 pm
Forum: programming
Topic: BBC BASIC detecting if it is being run on a BBC or Archimedes
Replies: 14
Views: 312

Re: BBC BASIC detecting if it is being run on a BBC or Archimedes

In practice that is not true of Raspberry Pi RISCOS. With one historical exception RISCOS 5.xx on the Pi defaults to 64 colours in BBC MODES, including MODE7 for some versions. Also all non-MODE7 BBC modes all have the same character size. This has proved to be most annoying when trying to get BBC ...
by jgharston
Sun Jan 17, 2021 10:05 pm
Forum: archive submissions
Topic: OS9 Hard Disc Image
Replies: 18
Views: 600

Re: OS9 Hard Disc Image

Master 128 doesn't like it! It just says This is not a language when trying *OS9 or *FX142. However it starts on a BBC B but doesn't get anywhere. I'll have to try the Xebec apparatus connected to a BBC B to see if it is actually waiting for the disc (hopefully) rather than the second processor. It...
by jgharston
Sun Jan 17, 2021 10:01 pm
Forum: 8-bit acorn hardware
Topic: B+ DFS & ADFS versions for PAGE E00
Replies: 10
Views: 814

Re: B+ DFS & ADFS versions for PAGE E00

Some interfaces did indeed put ROM at 8000-9FFF and RAM at A000-BFFF in the same socket.
by jgharston
Sun Jan 17, 2021 1:48 am
Forum: programming
Topic: BBC BASIC detecting if it is being run on a BBC or Archimedes
Replies: 14
Views: 312

Re: BBC BASIC detecting if it is being run on a BBC or Archimedes

I've written a program in BASIC for the BBC Micro which I also want to run on an Archimedes emulator on a Raspberry Pi . On the Archimedes, the colour palette is different. Is there a command in BBC Basic that will return a unique result for BBC Micro so I can set one set of colours for the BBC and...
by jgharston
Sun Jan 17, 2021 1:32 am
Forum: 8-bit acorn software: other
Topic: Econet Find Open option 6
Replies: 3
Views: 123

Re: Econet Find Open option 6

You can translate the received flags to open operations with:
if Rx7=0 then
operation=OPENOUT
else
if Rx8=0 then operation=OPENUP else operation=OPENIN
endif
by jgharston
Sun Jan 17, 2021 1:28 am
Forum: 8-bit acorn software: other
Topic: Econet Find Open option 6
Replies: 3
Views: 123

Re: Econet Find Open option 6

I am expecting a value of either 1 or 0 but sometimes it is 2 from the client for the readonly flag. That's your problem. It's not 1 or 0, it's non-zero or zero. grrr. why isn't there's a 'monospace font' option.... Find (OPEN) Function Code=6 =======================================================...
by jgharston
Sun Jan 17, 2021 12:47 am
Forum: programming
Topic: Teletext paint program
Replies: 388
Views: 19566

Re: Teletext paint program

Going back on topic, this has distracted me from doing some real work, and have been digging through my Teletext stuff, and trying to organise all my teletext pages into some sort of organised structure. ;)
by jgharston
Sun Jan 17, 2021 12:43 am
Forum: programming
Topic: Teletext paint program
Replies: 388
Views: 19566

Re: Teletext paint program

FFFF7C00 even betterer ;) Not necessarily! In Matrix Brandy (having selected MODE 7 in immediate mode): PRINT ?&7C00 62 PRINT ?&FFFF7C00 Address exception Of course you may argue that it's Brandy that's misbehaving. In my BASICs I don't attempt to emulate the MODE 7 screen being at &7C0...
by jgharston
Sat Jan 16, 2021 9:16 pm
Forum: programming
Topic: Teletext paint program
Replies: 388
Views: 19566

Re: Teletext paint program

Soruk wrote:
Sat Jan 16, 2021 12:01 pm
fuzzel wrote:
Sat Jan 16, 2021 11:03 am
(I was hoping it would save it as a 1k teletext file which I can import to an ssd disc and load into &7B00 in Beebem).
&7C00 would work better :)
FFFF7C00 even betterer ;)
by jgharston
Sat Jan 16, 2021 9:12 pm
Forum: programming
Topic: Beebasm question
Replies: 5
Views: 115

Re: Beebasm question

iainfm wrote:
Sat Jan 16, 2021 6:07 pm
But the assembler throws

error: Indirect mode not allowed for this instruction.
LDA (L2D47 AND &FF00 DIV &FF)
Just use DIV. It's a 16-bit number, so it's not going to wrap.
And it's DIV 256 !

Code: Select all

LDA #L2D47 AND 255 \ low byte
STA &8C
LDA #L2D47 DIV 256 \ high byte
STA &8D
by jgharston
Sat Jan 16, 2021 9:05 pm
Forum: software & utilities for the pc, mac or unix
Topic: RS232 Disk Image transfer BBC -> PC
Replies: 5
Views: 311

Re: RS232 Disk Image transfer BBC -> PC

Doesn't XFER have that built in? It's many years since I used it, but a quick skim of the documentation says there's a 'disk dump' option. Plus, any system that presents the PC as a filing system to the BBC will allow you to use any image-to-file tool such as these . Eg: DiskToImg, source=0, dest=-h...
by jgharston
Fri Jan 15, 2021 6:25 pm
Forum: off-topic
Topic: Can Camera GPS Data Be Wrong?
Replies: 4
Views: 234

Re: Can Camera GPS Data Be Wrong?

Was it the raw data from a digital camera? Or was it a scan from a paper photo? Has it been resized/edited/etc? In which has it will be the coordinates of the person doing the scannning - if their scanner enters location details into the output image. Photo EXIF data is just data, anything can chang...
by jgharston
Fri Jan 15, 2021 6:15 pm
Forum: software & utilities for the pc, mac or unix
Topic: Hex Dump Utilities
Replies: 8
Views: 227

Re: Hex Dump Utilities

A hexdump tools is one of the first things I ever write the first time I get my hands on a new system
fdump first version from university.
fdump written about three days into working at AFE.

Note the improvement in coding style. ;)

Both still work happily on CentOS today. :)
by jgharston
Thu Jan 14, 2021 7:15 pm
Forum: 8-bit acorn hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 290MHz)
Replies: 1325
Views: 183319

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 290MHz)

At some point the default error handler changed from IF QUIT ERROR EXT ERR,REPORT$ ELSE RESTORE:IF ERL:!(HIMEM-4)=@%:@%=&90A:REPORT:PRINT" at line ";ERL:@%=!(HIMEM-4) ELSE REPORT:PRINT to IF QUIT ERROR EXT ERR,REPORT$ ELSE RESTORE:IF ERL CALL!ERRXLATE:PRINT$STRACC ELSE REPORT:PRINT pre...
by jgharston
Thu Jan 14, 2021 6:56 pm
Forum: 8-bit acorn hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 290MHz)
Replies: 1325
Views: 183319

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 290MHz)

I get the same behaviour on the Native ARM, but it's any * command, not just a Bad command error. Also the program corruption occurs with or without a * command: It's not corrupting the current program, because you've done NEW, so there *is* no BASIC program. Absolutely anything is allowed to happe...
by jgharston
Thu Jan 14, 2021 6:51 pm
Forum: 8-bit acorn hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 290MHz)
Replies: 1325
Views: 183319

Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 290MHz)

I think I found a bug in the Native ARM co-pro. It appends the line number of last line of BASIC to an OS command error in immediate mode. capture217.png You've pressed BREAK then done OLD. Is that actually any code in there? You've 'OLD'ed random data, so the error handler is going to get confused...
by jgharston
Thu Jan 14, 2021 6:48 pm
Forum: programming
Topic: assembler noob
Replies: 17
Views: 330

Re: assembler noob

If you're careful you can write position-independent code in 6502, but things like subroutines are difficult. PALSUB.S is a simple example. No subroutines within its own code, and code flow is all via branches. When you start doing code that needs to make memory references to itself or make subrouti...
by jgharston
Thu Jan 14, 2021 6:38 pm
Forum: programming
Topic: assembler noob
Replies: 17
Views: 330

Re: assembler noob

Thanks, I didn't realise JMP was absolute. Why would I when it uses a label. I'm also getting confused about what BASIC commands you can use in assembler, e.g. LDA myaddr%+1 seems to work, I assume that also becomes an absolute address? You can't use *any* BASIC commands within the assembler, you c...
by jgharston
Thu Jan 14, 2021 6:31 pm
Forum: programming
Topic: BBC Micro co-processor graphics compression
Replies: 3
Views: 233

Re: BBC Micro co-processor graphics compression

I'm not sure if it's just under BeebEm, but I noticed that the tube host was executing code in zero page when I was trying to debug my audio code. I remember because I thought it was strange that code was jumping to zero page, I thought at first there was a bug in my interrupt handler. Yes, when th...
by jgharston
Mon Jan 11, 2021 11:27 am
Forum: 8-bit acorn hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 188
Views: 19078

Re: SpectROM - Speccy emulator for the Pi co-pro

Loading the rom using srload works, but if i have ADFS 57 to use the mmc like a hard driv, and when this rom is paged you cant use srload. And all the shenanigans to srload something and then switch to ADFS are a pain and most times i can't get them to work. ADFS is a pain, it doesn't like its work...
by jgharston
Sun Jan 10, 2021 1:02 pm
Forum: off-topic
Topic: Aliexpress VAT
Replies: 14
Views: 384

Re: Aliexpress VAT

Elsewhere there's a "Nerdy Customs Thread" where I've asked some nerdy customs questions, so light may be forthcoming.

(My brother used to run a greengrocer's, and the VAT regulations book he had to refer to was an inch thick!)

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