Search found 2902 matches

by jgharston
Sun Feb 18, 2018 5:07 pm
Forum: emulators
Topic: When should keyboard interrupts be enabled during startup?
Replies: 4
Views: 75

Re: When should keyboard interrupts be enabled during startup?

.LDA03 \**+********** set up system VIA ***************************************** LDX #&0F :\ set PORT B to output on bits 0-3 Input 4-7 STX LFE40+2 .LDA08 \* set addressable latch IC 32 for peripherals via PORT B */ DEX :\ loop start STX LFE40 :\ write latch IC32 CPX #&09 :\ is it 9 BCS LD...
by jgharston
Sun Feb 18, 2018 4:21 pm
Forum: development tools
Topic: Couple of BeebASM usage questions.
Replies: 10
Views: 221

Re: Couple of BeebASM usage questions.

That's why we need ifdef/ifndef so we can do things like: ifndef ISROM ISROM=0 ; Default to not building a ROM endif or even ifdef ISROM ifdef SYS40 save "rom\sys5-1770-40.rom",start,end,entry else save "rom\sys5-1770-80.rom",start,end,entry endif endif Adding ifdef/ifndef to Asm...
by jgharston
Fri Feb 16, 2018 2:40 am
Forum: development tools
Topic: Couple of BeebASM usage questions.
Replies: 10
Views: 221

Re: Couple of BeebASM usage questions.

Checking the source, SAVE does not impose any rules on the parsed filename, just stores it in a variable, and later on the code that saves to a disk image does something like: dir ='$' if filename[1]='.' then dir=filename[0]; filename=filename[2...]; filename=left(filename+padding,7); so, SAVE "...
by jgharston
Fri Feb 16, 2018 2:23 am
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3282

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

KenLowe wrote:I found a dos utility (SPCONV) that can covert between z80 and sna formats, but it doesn't work on x64 windows machines.

Also on RISC OS, and can be done on BBC/Master (and DOS/Windows) in two steps with SnapToBIN followed by BINtoSnap.
by jgharston
Fri Feb 16, 2018 2:19 am
Forum: hardware
Topic: SpectROM - Speccy emulator for the Pi co-pro
Replies: 113
Views: 3282

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

I've heard of someone using the BBC Master shadow memory in order to double the vertical resolution with interlacing. Yes - I remember typing in a program that did this from Acorn User. Unfortunately, my monitor wasn't happy with it (or maybe I made a typo!) I remember that one, my eyes weren't ver...
by jgharston
Fri Feb 16, 2018 2:16 am
Forum: software: other
Topic: BBC Basic for Z80
Replies: 32
Views: 1557

Re: BBC Basic for Z80

I have successfully imported the JGHCPM1 image and created a HDBIOS. However when I boot into the C drive, It can take approx 2 mins for the C prompt to appear. Yep, well what would you expect, building a disk map for a 8M disk compared to building a disk map for a 400K disk? :) I've just done a qu...
by jgharston
Fri Feb 16, 2018 1:47 am
Forum: development tools
Topic: Couple of BeebASM usage questions.
Replies: 10
Views: 221

Re: Couple of BeebASM usage questions.

If Jonathan's suggestion doesn't work, we could consider adding explicit support for this - although I guess the resulting SSD wouldn't be valid on a BBC. Perhaps we could add a '--atom' command line option to change the validation rules? It works on a BBC, you do *DIR " " Ideally, you sh...
by jgharston
Thu Feb 15, 2018 1:45 pm
Forum: development tools
Topic: Couple of BeebASM usage questions.
Replies: 10
Views: 221

Re: Couple of BeebASM usage questions.

Files are saved in $ by default, I'm not sure how you change that, but to rearrange files in an SSD, I used to load the image in beebem and then use the windows paste option to "script" processing file names. Does BeebAsm support, eg SAVE "a.file" if so would SAVE ".file&qu...
by jgharston
Thu Feb 15, 2018 1:41 pm
Forum: hardware
Topic: Myelin's in-system updateable MegaROM for the BBC Master 128
Replies: 14
Views: 588

Re: Myelin's in-system updateable MegaROM for the BBC Master 128

danielj wrote:I can safely say it fits without getting in the way of anything in mine, which has MultiOS, Econet and 80186 inside it...
Wonderful. Just need somebody to unsolder my VULA and socket it.
by jgharston
Wed Feb 14, 2018 8:43 pm
Forum: hardware
Topic: Myelin's in-system updateable MegaROM for the BBC Master 128
Replies: 14
Views: 588

Re: Myelin's in-system updateable MegaROM for the BBC Master 128

DualOS and GoMMC just don't quite fit together. I was wondering if there was some way of shaving the side of an IC header down a bit.

Image
by jgharston
Wed Feb 14, 2018 8:35 pm
Forum: hardware
Topic: Myelin's in-system updateable MegaROM for the BBC Master 128
Replies: 14
Views: 588

Re: Myelin's in-system updateable MegaROM for the BBC Master 128

My GoMMC is in the socket next to the MOS ROM as it needs to be in a 32K socket, so it will bmp into it. However, a couple or three IC sockets used as raisers may rise it high enough to overlap the GoMMC. While I've got my lid off, I may as well take a photo. :) Hmmm.... there's a thought. Where's t...
by jgharston
Wed Feb 14, 2018 8:30 pm
Forum: software: other
Topic: Desktop for CF/SD cards, Datacentre RAM/USB & MMC cards
Replies: 4
Views: 249

Re: Desktop for CF/SD cards, Datacentre RAM/USB & MMC cards

Some initial notes: I couldn't get keyboard operation to work. I hammmered and hammered away at the RETURN key and nothing happened. You find out what platform you're running on with OSBYTE 0 , not by peeking random memory locations. A%=0:X%=1:os%=((USR&FFF4)AND&FF00)DIV256 then later do thi...
by jgharston
Wed Feb 14, 2018 7:30 pm
Forum: hardware
Topic: Myelin's in-system updateable MegaROM for the BBC Master 128
Replies: 14
Views: 588

Re: Myelin's in-system updateable MegaROM for the BBC Master 128

Which way around does it plug in? It looks like it will either clash with my network card or clash with my GoMMC.
by jgharston
Mon Feb 12, 2018 2:42 am
Forum: hardware
Topic: Screen shadow memory
Replies: 18
Views: 516

Re: Screen shadow memory

I have a Waterford electronics 32k ram-card which needs a ROM to run it, but not really played with it much, still need to make up a new cable that connects it to the CPU socket as the one with it is dodge. Peter. The shadow screen control ROMs I've got are at: http://mdfs.net/System/ROMs/Display/S...
by jgharston
Mon Feb 12, 2018 2:40 am
Forum: development tools
Topic: BeebAsm
Replies: 30
Views: 1847

Re: BeebAsm

Thanks Kieran. I'd like to give those people (JGH? hoglet? sweh? others?) who were interested in 'ifdef'-type stuff time to comment on ctr's changes before we push them into v1.09, but personally I'm pretty happy with them Probably because it's 2:30am and I've been coding all night, but I can't fin...
by jgharston
Sun Feb 11, 2018 6:09 pm
Forum: hardware
Topic: Screen shadow memory
Replies: 18
Views: 516

Re: Screen shadow memory

That sounds very interesting. How much RAM does it have and does it map any leftover RAM to anywhere else in the address map? The Aries card allowed you to use the 32K RAM as either: 2 x 16K SRAM in bank 13 and 14 1 x 16K SRAM in bank 14 + 16K shadow RAM (MODE 0/1/2 have HIMEM at &7000) 1 x 12K...
by jgharston
Sun Feb 11, 2018 5:49 pm
Forum: programming
Topic: ADFS Format
Replies: 20
Views: 701

Re: ADFS Format

I've updated my ADFS format documentation correcting some errors I and others have spotted, and trying to clarify a few points, particularly where I'd glossed over between offsets into a disk image and logical sector offsets into a physical disk. I'm afraid even reading your version of 'new maps' I ...
by jgharston
Sun Feb 11, 2018 3:59 pm
Forum: other vintage computer hardware, software and games
Topic: GoTek Floppy - MDFS
Replies: 5
Views: 212

Re: GoTek Floppy - MDFS

There's a couple of MDFS disk images here you can use for testing: http://mdfs.net/Mirror/Image/SJ/MDFS/ FLOPPY is a blank disk, other than two directories with sample access strings and account numbers, MASTER is a master startup disk. MDFS floppies are 1024 bytes x 5 sectors x 2 sides x 80 tracks ...
by jgharston
Sun Feb 11, 2018 3:46 am
Forum: emulators
Topic: Beebem teletext hold char (158) issue
Replies: 37
Views: 1123

Re: Beebem teletext hold char (158) issue

Yes, this needs adding to the documentation. (Previously, that was buried at the end of OpList, so I pulled it out into its own document.)
by jgharston
Sun Feb 11, 2018 12:00 am
Forum: emulators
Topic: Beebem teletext hold char (158) issue
Replies: 37
Views: 1123

Re: Beebem teletext hold char (158) issue

I've been debugging some of the Emulator Trap stuff, don't let that delay releasing a version of BeebEm without the EMTRAPs branch. In fact, that would be useful to me as it would be useful to ensure the EMTRAP branch builds correctly with a fresh new release of the core non-EMTRAP code.
by jgharston
Sat Feb 10, 2018 11:48 pm
Forum: programming
Topic: Sideways ROMs, Ctrl-Break and running from SWRAM
Replies: 4
Views: 192

Re: Sideways ROMs, Ctrl-Break and running from SWRAM

This is an annoying "feature" of ADFS. If you load a sideways ROM in a bank higher than ADFS which claims workspace, Ctrl-Break gives you 'Checksum error' as ADFS's workspace is now somewhere else and naturally doesn't have the data in it that it expects. You have to do *FX200,3 then Ctrl-...
by jgharston
Fri Feb 09, 2018 10:32 pm
Forum: software: other
Topic: BBC Basic for Z80
Replies: 32
Views: 1557

Re: BBC Basic for Z80

You need RAMTrap which diverts OSWORD &7F and leaves everything else in place.
by jgharston
Wed Feb 07, 2018 8:51 pm
Forum: software: other
Topic: BASIC weirdness
Replies: 9
Views: 302

Re: BASIC weirdness

I tripped over a similar gotcha when testing some code on BBC BASIC for Windows, which allows 65535-character strings. A subroutine was something like: DEFPROCfred($address), and the program kept falling over running out of memory, and in digging away suddenly realised that there was no <cr> anywher...
by jgharston
Wed Feb 07, 2018 8:46 pm
Forum: programming
Topic: ADFS Format
Replies: 20
Views: 701

Re: ADFS Format

Hi Jonathan - I noticed that your page: http://mdfs.net/Docs/Comp/Disk/Format/ADFS has reverted back to an older version, as it now refers to the directory identifiers as being 'MICK' and not 'NICK'. Could this have happened when you had your domain issue? Could be. I've just checked my archive of ...
by jgharston
Wed Feb 07, 2018 8:40 pm
Forum: hardware
Topic: OS RAM module
Replies: 84
Views: 4948

Re: OS RAM module

Dynamic workspace can be anywhere, but absolute workspace is, as per the name, at a fixed absolute address starting at &0E00. However, as others have pointed out, many - possibly most - ROMs use an "impossible" address such as >=&8000 to mean "disabled". Languages' works...
by jgharston
Tue Feb 06, 2018 2:56 pm
Forum: hardware
Topic: Thought experiment: Iomega zip drive for the BBC
Replies: 10
Views: 347

Re: Thought experiment: Iomega zip drive for the BBC

I had a fiddle with a Zip drive back in the 90s. Lots of piles of wire with no success. I think I still have the hacked-up printer lead for it womewheree.
by jgharston
Sun Feb 04, 2018 10:18 pm
Forum: acorn atom
Topic: Abasic2/3 and SBasic2/3
Replies: 17
Views: 562

Re: Abasic2/3 and SBasic2/3

Right, I've been merging the changes into my BeebASM version of the source, with a view to combining the 1770 disk routines form my Atom interface, I may actually prototype with one of the Atom boards as they are essentially the same bus :) Noticed one thing, the jump to EXEC a boot file in the blo...
by jgharston
Sun Feb 04, 2018 2:52 am
Forum: emulators
Topic: BBC emulator HTTP API
Replies: 15
Views: 499

Re: BBC emulator HTTP API

But calling arbitrary code is rather difficult to do safely. ... Though, now that I think about this... how would this even work? I think what you'd have to do is the emulator finishes the current instruction, pushes the the flags and current PC, then sets the PC to the jumped-to address. That allo...
by jgharston
Sun Feb 04, 2018 2:37 am
Forum: acorn atom
Topic: Abasic2/3 and SBasic2/3
Replies: 17
Views: 562

Re: Abasic2/3 and SBasic2/3

Update, and probably finished: SYS5-40.zip - System 5 8271 DOS and Teletext Kernel, teletext conversion now done on OSRDCH as well. SYS5-1F.zip - System 5 8271 DOS and Kernel source, with switches for 40/80 VDU, teletext character conversion, disk speeds and SPOOL/EXEC optimisation. From the documen...
by jgharston
Sat Feb 03, 2018 3:20 am
Forum: acorn atom
Topic: Abasic2/3 and SBasic2/3
Replies: 17
Views: 562

Re: Abasic2/3 and SBasic2/3

Here we are, a bit of tidying and I've put the printer code back in again: SYS5-40.zip - System 5 8271 DOS and Teletext Kernel SYS5-1F.zip - System 5 8271 DOS and Kernel source, with switches for 40/80 VDU and disk speeds. vdu%=40, vdutrans%=TRUE, execsp%=TRUE builds the above ROM. Currently there a...