Search found 2189 matches

by sweh
Sun Aug 09, 2020 9:11 pm
Forum: 8-bit acorn software: other
Topic: DDFS File Format, Archiving & Emulators
Replies: 21
Views: 351

Re: DDFS File Format, Archiving & Emulators

Because Opus uses sub-drives it doesn't have the "we need to steal bits from elsewhere" problem Solidisk does. Thank you Stephen - I didn't know Opus did that - not sure what an Opus sub-drive is either, loved the look of the drives as a child but know so little about them frankly. How did they ext...
by sweh
Sun Aug 09, 2020 4:59 pm
Forum: 8-bit acorn software: other
Topic: DDFS File Format, Archiving & Emulators
Replies: 21
Views: 351

Re: DDFS File Format, Archiving & Emulators

OK didn't know the BBC had those - figured it was limited by the spare bits in Sector 1 - Solidisk uses 11-bit across two bytes as it is. What DFS used that? Curious to know! Learn something new every day. Solidisk used 16*80. Opus DDOS used 18*80. Because Opus uses sub-drives it doesn't have the "...
by sweh
Sun Aug 09, 2020 3:28 pm
Forum: 8-bit acorn hardware
Topic: Serial Port Failure?
Replies: 4
Views: 148

Re: Serial Port Failure?

You may want to create a dumb loopback cable first (connect CTS to RTS, connect Rx to Tx) and use a terminal emulator. Type on the keyboard and see if the characters show up on the screen (ensure local echo is off! I think this is the default for Master TERMINAL). If you do get echo then it's likely...
by sweh
Mon Aug 03, 2020 2:27 am
Forum: introduce yourself
Topic: Hello from Canvey Island
Replies: 8
Views: 189

Re: Hello from Canvey Island

Greetings from another Canvey Island person... although I moved to New York 20 years ago! PS: Sun SPARC, not Spark :-) I still have a couple in my basement (Ultra2, Ultra5)... but I doubt I'll ever power 'em up again. Spuddy ran on a SPARC 2 :-) https://sweh.spuddy.org/Previous/old-website/ I'm actu...
by sweh
Tue Jul 28, 2020 10:38 pm
Forum: off-topic
Topic: Ext4 Bad Sectors
Replies: 20
Views: 567

Re: Ext4 Bad Sectors

You should possibly also do a "smartctl -a /dev/sda" and look at the results. Important values include 5 Reallocated_Sector_Ct 187 Reported_Uncorrect 188 Command_Timeout 197 Current_Pending_Sector 198 Offline_Uncorrectable Generally it's the last field that holds the value you care about. On a healt...
by sweh
Tue Jul 28, 2020 1:32 am
Forum: development tools
Topic: BeebAsm
Replies: 113
Views: 12950

Re: BeebAsm

And you can remove that annoyance as well if you're using Beeblink! At few months ago (before there were any emulators that did perfect CRTC emulation), when I needed to iterate at speed on stuff I had my Master set up with Beeblink, and I could hit 'build' in Visual Studio Code (which spawned Beeb...
by sweh
Mon Jul 27, 2020 1:27 am
Forum: programming
Topic: Adding a delay to loop in BASIC
Replies: 15
Views: 546

Re: Adding a delay to loop in BASIC

Since each machine runs at different speeds (and co-processors can make this even worse) maybe you should start your program with a simple counter loop and see how many times you loop Maybe something like T%=TIME+200:REPEAT:LET A=A+1:UNTIL TIME>T% Now you have some rough value. Maybe it takes 950 it...
by sweh
Mon Jul 27, 2020 1:08 am
Forum: development tools
Topic: BeebAsm
Replies: 113
Views: 12950

Re: BeebAsm

You should just be able to do

Code: Select all

LDA #'Y'
and not need ASC at all.

eg

Code: Select all

$ cat x
ORG &2000
LDA #'Y'

$ beebasm -v -i x
     2000   A9 59      LDA #&59
Processed file 'x' ok

We can see the 'Y' became &59
by sweh
Fri Jul 24, 2020 9:42 pm
Forum: general
Topic: SD Card on Fire
Replies: 31
Views: 909

Re: SD Card on Fire

I'd like to read the "CID" on as many of these cards as possible but it seems I can't do it from a USB card reader. Pi's OS card is OK, but not a card in the reader: USB card readers present to the OS as a "USB Mass Storage" device. These devices don't have a call to expose the CID, so the OS can't...
by sweh
Fri Jul 17, 2020 10:18 pm
Forum: 8-bit acorn software: other
Topic: Name of the CRC from the Advanced User Guide?
Replies: 6
Views: 394

Re: Name of the CRC from the Advanced User Guide?

The code on page 348 initializes with zero. My perl code also initializes with zero. bbcim also initializes with zero. Using bbcim: % bbcim -e demo.ssd ... % cat demo.ssd.Code.inf $.Code 1100 1100 CRC=AFFE Using my perl code: % beeb getfile demo.ssd X Saving $.!Boot as !Boot Saving $.Code as Code % ...
by sweh
Fri Jul 17, 2020 2:55 am
Forum: programming
Topic: Beginner question on interrupts
Replies: 14
Views: 683

Re: Beginner question on interrupts

I know this may be heresy but if the objective is just a regular (or irregular) "pulse" to drive some process rather than a deep understanding of the hardware then you might want to investigate the event handlers. These are pre-packaged interrupts with none of the messing around with hardware addre...
by sweh
Thu Jul 16, 2020 3:21 pm
Forum: programming
Topic: Big machine code programs
Replies: 14
Views: 467

Re: Big machine code programs

Back in the day I used a ROM assembler; originally ASM but then the free Lancs 65C02 assembler. This reads and writes to disk, so size isn't an issue.

Modern development I do on Linux with beebasm and then just copy the result to the Beeb.
by sweh
Tue Jul 14, 2020 2:36 am
Forum: programming
Topic: Filing systems and closing EXEC files
Replies: 6
Views: 274

Re: Filing systems and closing EXEC files

I think that if the OS itself called "close#0" on a OSBYTE &77 then we'd have seen problems long before now. I agree that it's a nice sanity check, but we don't always have the space and luxury and have to trust the OS. I think if you're calling OSBYTE &77 as part of 'CLOSE#0' then you're good enoug...
by sweh
Tue Jul 14, 2020 2:08 am
Forum: programming
Topic: Filing systems and closing EXEC files
Replies: 6
Views: 274

Re: Filing systems and closing EXEC files

EDIT: how does this even work though?! OSFIND calls OSBYTE $77, and OSBYTE $77 calls OSFIND again... to close the same handle? I wonder how/why this works. Maybe this is the Master's OS being cleverer, and maybe it won't work on a model B. Ugh. Perhaps what I should actually be doing is what you su...
by sweh
Wed Jul 08, 2020 5:40 pm
Forum: programming
Topic: Self Modifying Code
Replies: 12
Views: 573

Re: Self Modifying Code

Some OS's or loaders may also block it eg by marking any writeable page as non-executable and marking all executable pages as read-only.

So even if the hardware can handle it, the execution environment might make it very difficult :-)
by sweh
Wed Jul 08, 2020 2:43 am
Forum: programming
Topic: Self Modifying Code
Replies: 12
Views: 573

Re: Self Modifying Code

BITD, self modifying code was also used for copy protection. Thinking back, the routine used a timer to generate a consistent sequence of bytes that were EOR'd against the loaded code. Once the decoding was complete they just jumped to the main entry point. Of course if you single-stepped through th...
by sweh
Tue Jul 07, 2020 12:59 am
Forum: development tools
Topic: BeebAsm
Replies: 113
Views: 12950

Re: BeebAsm

Hmm, what version of debian are you using? On "buster" (Debian 10) on amd64 I did exactly the "git clone ; cd ; make all" process and it "just worked" "Linux Support Patch" makes me think you might be building on Linux Subsystem for Windows, and not native Linux. or some other weird setup? Seeing th...
by sweh
Tue Jul 07, 2020 12:43 am
Forum: 32-bit acorn hardware
Topic: Serial to ethernet adaptor (?) - Free for someone to play with!
Replies: 6
Views: 347

Re: Serial to ethernet adaptor (?) - Free for someone to play with!

Haha, yes. That's nothing to do with serial, but old-school "thick net" (10base5) networking. You've got a thick-net to thin-net (10base2) MAU. Thick-net was "fun". You would apply a vampire tap to the main cable. You _had_ to place it at specific places on the cable (the cable had marks on it) and ...
by sweh
Mon Jul 06, 2020 4:50 am
Forum: modern implementations of classic programming languages
Topic: Matrix Brandy BASIC VI for console and SDL1.2: V1.22.7 released
Replies: 1173
Views: 75718

Re: Matrix Brandy BASIC VI for console and SDL1.2: V1.22.6 released

I'm wondering if we need two different variables, for compatibility. TIME being 32bit and TIME%% being 64bit. 'Cos otherwise "x%=TIME" might not produce the expected result after 228 days.
by sweh
Sun Jul 05, 2020 7:06 pm
Forum: programming
Topic: IF INKEY-xy
Replies: 14
Views: 492

Re: IF INKEY-xy

AJW wrote:
Sun Jul 05, 2020 6:28 pm
Strange how I can do:

Code: Select all

LDX#(-102 AND&FF)
but not:

Code: Select all

CPX#(-1)
It has to be 255
In both case the value has to be between 0 and 255 (inclusive) so the equivalent would be

Code: Select all

CPX#(-1 AND &FF)
by sweh
Sun Jul 05, 2020 7:02 pm
Forum: 8-bit acorn emulators
Topic: Using Beeb.mmb with an emulator?
Replies: 8
Views: 312

Re: Using Beeb.mmb with an emulator?

steve3000 wrote:
Sun Jul 05, 2020 12:34 pm
However what is not explained, is that the mmc.cfg file must not contain a return (or anything else) after the end of the new filename!
OK, that's quite a gotcha! Would explain why I never got that to work when I last played with it a couple of years ago...
by sweh
Mon Jun 29, 2020 1:03 pm
Forum: programming
Topic: PHA around JSR
Replies: 10
Views: 422

Re: PHA around JSR

Save the accumulator to memory. Stick it in a zero page location. It's faster than using the stack. PHA is one byte and takes 3 cycles; PLA is one byte and takes 7 cycles. So 2 bytes and 7 cycles. STA &70 is 2 bytes and takes 3 cycles; LDA &70 is 2 bytes and takes 3 cycles. So 4 bytes and 6 cycles,...
by sweh
Sun Jun 28, 2020 11:20 pm
Forum: programming
Topic: PHA around JSR
Replies: 10
Views: 422

Re: PHA around JSR

PHA:LDY&85:BEQno8:JSR clyr2:PLA results in "at Line ____" error , but when PHA and PLA are removed it seemingly works. Can anyone explain why? And if not possible how to preserve the accumulator outside of the subroutine? You probably want to put the PHA just before the JSR LDY&85:BEQno8:PHA:JSR cl...
by sweh
Tue Jun 16, 2020 2:05 am
Forum: 8-bit acorn hardware
Topic: Master Vs B
Replies: 24
Views: 704

Re: Master Vs B

I'm sure zalaga uses the 'illegal' opcodes in the 6502 so doesn't work The copy protection code definitely does (I remember that from BITD 'cos EXMON disassembly was painful; lots of scribbling notes to break it). I don't know if the run-time itself used it, once the copy protection was bypassed.
by sweh
Tue Jun 09, 2020 1:59 am
Forum: modern implementations of classic programming languages
Topic: Key features of BBC BASIC for Windows / SDL 2.0
Replies: 16
Views: 689

Re: Key features of BBC BASIC for Windows / SDL 2.0

Because of timezone differences I can't make the vABUGs, even though I want to (I'm in New York, and Saturdays are normally when I see my girlfriend). But if I did make them, BB4W and Brandy would definitely be of interest. The _history_ of BB4W and the original design decisions (compatibility, comp...
by sweh
Fri Jun 05, 2020 12:07 am
Forum: 8-bit acorn software: other
Topic: Applications using "virtual memory"?
Replies: 6
Views: 584

Re: Applications using "virtual memory"?

Solidisk Utility Disk 3 ("Macro BASIC") had paging functionality... The MACRO BASIC and LINKEDT utilities. ===================================== The MACRO BASIC and LINKEDT programs are designed for users who wish to extend infinitely the processing ability of the BBC machine. By this, we mean that ...
by sweh
Thu Jun 04, 2020 10:02 pm
Forum: programming
Topic: !Boot working?
Replies: 6
Views: 282

Re: !Boot working?

The "CLOSE #0" will close the filehandle that's being used for the *EXEC call at boot time, and so the !BOOT process will stop. That's why you don't see the "CHAIN PREMAIN" command show. Typically a cheat is to create a simple program and run that. eg > *TYPE !BOOT NEW 10 CLOSE#0 20 *FX21 30 CHAIN "...
by sweh
Sun May 31, 2020 2:58 pm
Forum: programming
Topic: SRLOAD and OSGbPb
Replies: 6
Views: 374

Re: SRLOAD and OSGbPb

For "quick load" on my Beeb, my ROM just checked there was enough free main-memory RAM (from OSHWM to HIMEM) and then just did an OSFILE "*LOAD" to fill the buffer, then moved the contents into SWRam. It's destructive to main memory contents, of course. If a file was too large for the buffer then it...
by sweh
Thu May 28, 2020 12:55 am
Forum: programming
Topic: Incrementing a 2-byte number
Replies: 14
Views: 676

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: 21
Views: 939

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 ...

Go to advanced search