Search found 78 matches

by roganjosh
Tue Sep 10, 2019 6:50 pm
Forum: other vintage computer hardware, software and games
Topic: Help needed with VIC20
Replies: 4
Views: 261

Re: Help needed with VIC20

Boydie wrote:
Mon Aug 12, 2019 10:26 am

Any ideas where to test, or recommendations for forums which will offer stardot-level troubleshooting?
The forum->Help&Support section at https://www.lemon64.com is useful for troubleshooting.
by roganjosh
Fri Sep 06, 2019 9:41 pm
Forum: programming
Topic: Row multiplication table substitution
Replies: 13
Views: 344

Re: Row multiplication table substitution

The problem with Battletank is that the main part "TANK" (load addr 900, length 2e00) references OS ROM addresses ($c620 onwards) notably but not limited to: 2e9c lda $c620,y 2ea1 lda $c621,y That OS block looks to be an area where there is a good mix of positive and negative bytes. I'm guessing tha...
by roganjosh
Fri Sep 06, 2019 2:32 pm
Forum: programming
Topic: Row multiplication table substitution
Replies: 13
Views: 344

Re: Row multiplication table substitution

Thanks. I'll add it to my list of mysterious things.
by roganjosh
Fri Sep 06, 2019 11:10 am
Forum: programming
Topic: Row multiplication table substitution
Replies: 13
Views: 344

Re: Row multiplication table substitution

Yes indeed. I've met all of those in abundance plus, of course, the user defined graphics stuff. Then there are the ones making calls into the BASIC2 ROM (e.g. 3D Snooker). There is one site which documents useful calls in BASIC 4 but none for BASIC 7 (it just duplicates the BASIC 4 info, intended a...
by roganjosh
Wed Sep 04, 2019 5:46 pm
Forum: programming
Topic: Row multiplication table substitution
Replies: 13
Views: 344

Re: Row multiplication table substitution

=D> Yaay! thank you. Would you mind keeping notes as to which games work 'as is' and which ones you have had to alter? I know some BASIC listings do a CALL &D9CD on exit instead of the CALL!-4 which would work on both machines, so don't forget to see if they 'BREAK' OK :D Lee. I'll be happy to star...
by roganjosh
Wed Sep 04, 2019 2:52 pm
Forum: programming
Topic: Row multiplication table substitution
Replies: 13
Views: 344

Re: Row multiplication table substitution

That's just what I did earlier, thanks, as well as trapping screen clears. You have a good memory as there was also an IRQV restore to fix. Some of those are perverse: they sometimes go to the trouble of saving the old vector as an exit point but don't use those values to do any restoration, preferr...
by roganjosh
Wed Sep 04, 2019 6:23 am
Forum: programming
Topic: Row multiplication table substitution
Replies: 13
Views: 344

Re: Row multiplication table substitution

Thanks for the confirmation. Coincidentally it was Contraption that I was looking at. Unfortunately the Master zero page locations don't seem to be comprehensively documented anywhere that I can see. The MRF(1) only lists D0-FF as MOS workspace (as does the ARM). The NAUG gives the usual Model B des...
by roganjosh
Tue Sep 03, 2019 5:27 pm
Forum: programming
Topic: Row multiplication table substitution
Replies: 13
Views: 344

Row multiplication table substitution

As is well known, the vector at e0,1 on a BBC B points to the row multiplication table in the ROM. Porting software from B to Master often involves implementing alternative different ways to read the table. However I've hit some Model B code that writes to e0,1 so invoking a different table and ther...
by roganjosh
Thu Aug 29, 2019 1:37 pm
Forum: software: other
Topic: Odd GCOLs & PLOTs
Replies: 7
Views: 305

Re: Odd GCOLs & PLOTs

Thanks. Much appreciated.
by roganjosh
Thu Aug 29, 2019 12:20 pm
Forum: software: other
Topic: Odd GCOLs & PLOTs
Replies: 7
Views: 305

Odd GCOLs & PLOTs

In doing some software porting I've come across the following statements: GCOL 44,1 GCOL 43,3 PLOT 77,x,y The user guide states that the first parameter to GCOL should be in the range 0-4. It also states that PLOT values 72-79 are reserved. I can't see any blatantly obvious logical masks in BASIC2 -...
by roganjosh
Sun Aug 25, 2019 5:42 pm
Forum: software: other
Topic: Tube host code ROMs
Replies: 3
Views: 200

Re: Tube host code ROMs

Brilliant. Thanks to you both.

Alan
by roganjosh
Sun Aug 25, 2019 1:03 pm
Forum: software: other
Topic: Tube host code ROMs
Replies: 3
Views: 200

Tube host code ROMs

One of my Model Bs came with a WE DDB2 DDFS board and the WE 1.53 ROM. A quick browse of the ROM for addresses looking like tube host calls didn't look promising. Unless someone has a version of that DDFS code hacked to contain the tube stuff I'm left wondering what the most exciting ROM might be wh...
by roganjosh
Sun Aug 25, 2019 5:14 am
Forum: hardware
Topic: Fixed: Mode 7 intermittent lines
Replies: 40
Views: 1012

Re: Fixed: Mode 7 intermittent lines

Good stuff. Well done.
Also, as you're very probably aware, a little wobbling of the display on changing mode is normal behaviour for many HDMI converters.
I go for the low profile crystals as they are unlikely to be NOS ones.

Alan
by roganjosh
Thu Aug 22, 2019 9:46 am
Forum: hardware
Topic: Fixed: Mode 7 intermittent lines
Replies: 40
Views: 1012

Re: Mode 7 intermittent lines

Thanks again folks, I will go down the route of: Trying the Beeb on a SCART TV to assess the quality of the direct output vs captured Source some components to swap out one at a time: IC43 SN74ALS04 Report back I also tried the OSSC I have that I usually run my Amiga and RiscPC from and it doesn't ...
by roganjosh
Thu Aug 22, 2019 6:32 am
Forum: hardware
Topic: Fixed: Mode 7 intermittent lines
Replies: 40
Views: 1012

Re: Mode 7 intermittent lines

All started off fine as I saw no interference/loss of sync but once the machine had warmed up for 5-10 mins it was back :( I guess the next thing to try is to look at some of the video timing associated ICs . At least I know it has a new 16MHz crystal now. I suspect that the lines are artefacts com...
by roganjosh
Sun Aug 18, 2019 11:33 am
Forum: hardware
Topic: Fixed: Mode 7 intermittent lines
Replies: 40
Views: 1012

Re: Mode 7 intermittent lines

What I will add is that every time the interference occurs, the video converter has to re-sync itself as if the video stream is interrupted/corrupted briefly. I had exactly the same issue on several Model Bs (horizontal lines & sync loss) as I've reported elsewhere. In all cases replacement of the ...
by roganjosh
Sat Aug 10, 2019 7:53 pm
Forum: general
Topic: Master spray job
Replies: 18
Views: 1234

Re: Master spray job

A year on from doing the spray job I can report that the colour of the case hasn't changed. Vinyl dye, as surmised, appears to provide a long lasting solution for hobbyists with a dislike of yellowed cases. I unashamedly include myself in that category. I had a quick look at their "Ivory" preparatio...
by roganjosh
Wed Jul 31, 2019 12:32 pm
Forum: off-topic
Topic: Windows 10....
Replies: 173
Views: 16678

Re: Windows 10....

I had problems with a previous upgrade. After a bit of head scratching the solution was to remove the antivirus software (in this case AVAST) before doing the W10 upgrade.

That's no help given your current state though. Good luck.

Alan
by roganjosh
Tue Jul 30, 2019 6:00 pm
Forum: emulators
Topic: Beebem & Osbyte $EA
Replies: 2
Views: 173

Re: Beebem & Osbyte $EA

Well, doing that you've just turned the Tube software off in an inconsistant way! lda #$ea ; Tube presense flag ldx #$00 ; Write &00 ldy #$00 ; Don't read jsr osbyte ; Do osbyte &EA,0,0 - turn Tube software off stx $70 rts Some filing systems read the OSBYTE &EA variable every time they do a data t...
by roganjosh
Tue Jul 30, 2019 1:51 pm
Forum: emulators
Topic: Beebem & Osbyte $EA
Replies: 2
Views: 173

Beebem & Osbyte $EA

I find that Beebem (Windows, 4.14) is having problems with Osbyte $EA when the Master 128 + 65Co2 coprocessor options are selected. The following example code: lda #$ea ldx #$00 ldy #$00 jsr osbyte stx $70 rts should leave $ff in location $70 if tube hardware & software is detected. Most of the time...
by roganjosh
Sat Jun 22, 2019 1:12 pm
Forum: programming
Topic: RNDX and Master
Replies: 8
Views: 364

Re: RNDX and Master

In Basic 4.32 (which I think is version 07) RND(x) starts at B302: https://github.com/hoglet67/BBCBasic4r32/blob/master/disassembly/Basic432.asm#L9889 Dave For completeness, after looking at the disassembly, it looks to me as though RNDX on Basic07 is at $aab0. So the full list is therefore: BASIC1...
by roganjosh
Sat Jun 22, 2019 8:14 am
Forum: programming
Topic: RNDX and Master
Replies: 8
Views: 364

Re: RNDX and Master

The $aa52 address is spot on for BASIC04 thanks. Unfortunately $b302 under BASIC07 throws a "No such variable error".

Alan
by roganjosh
Fri Jun 21, 2019 6:10 pm
Forum: programming
Topic: RNDX and Master
Replies: 8
Views: 364

Re: RNDX and Master

Thanks to you both. I'll give them a whirl.

Alan
by roganjosh
Fri Jun 21, 2019 5:04 pm
Forum: programming
Topic: RNDX and Master
Replies: 8
Views: 364

Re: RNDX and Master

Ta for the reply.

I'm doing the porting initially under BeebEm but also want to have it work under my real hardware. *ROMS gives '04' and '07' for those platforms. If I had to choose only one then it'd be '07'.
by roganjosh
Fri Jun 21, 2019 4:45 pm
Forum: programming
Topic: RNDX and Master
Replies: 8
Views: 364

RNDX and Master

I'm doing some porting from Model B to Master 128. One of the programs has a call to $af24 (BASIC2 ROM rndx). This causes a crash on BASIC 4. Given that the Advanced BASIC ROM User Guide only deals with BASIC1&2 is there such a thing that gives equivalent routine locations in BASIC 4? If not then, m...
by roganjosh
Mon Jun 10, 2019 7:56 pm
Forum: software: other
Topic: makegamedata
Replies: 1
Views: 266

Re: makegamedata

Enough time has passed, I hope, for replying to my own posting not to be bad netiquette. In the end I managed to get the elderly Visual Basic 6 installed on a Windows 10 laptop. An interesting diversion. That enabled me to boost the relevant arbitrary limit and produce a new version of makegamedata....
by roganjosh
Thu Jun 06, 2019 5:29 pm
Forum: software: other
Topic: makegamedata
Replies: 1
Views: 266

makegamedata

makegamedata is the program used by (e.g.) DCBEEB to convert program description files into a binary file used by the main menu program. Unfortunately the program was written in an early flavour of Visual Basic. The source code sets arbitrary array limits and it crashes out on my large dataset with ...
by roganjosh
Mon Jun 03, 2019 6:39 pm
Forum: hardware
Topic: Converting BBC Micro's to HDMI
Replies: 24
Views: 1411

Re: Converting BBC Micro's to HDMI

That would indeed fit with experience. Thanks.
My scope showed the signal at IC43 pin 6 as being very close to 16MHz. There was nothing grossly abnormal about the trace. I didn't bother with my dedicated frequency counter.

Alan
by roganjosh
Sun Jun 02, 2019 7:53 am
Forum: hardware
Topic: Converting BBC Micro's to HDMI
Replies: 24
Views: 1411

Re: Converting BBC Micro's to HDMI

Glad the info was useful. As an addendum to this I've just bought a spare Model B. It showed exactly the same sync problem with the Elephas converter. Having found from my first B that it wasn't particularly bothered by the shape of the sync pulses I headed straight for crystal X1 (16MHz) and replac...
by roganjosh
Sun May 19, 2019 6:37 pm
Forum: off-topic
Topic: LOLPRICE
Replies: 2936
Views: 267462

Re: LOLPRICE

One for the loaded collectors:

https://www.ebay.co.uk/itm/CABLETRONIC- ... 4204671594?

You could get 35 Jupiter Aces for that.