Custom Characters in cassette buffer

Basic and Machine Language

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Mobsie
Vic 20 Drifter
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Joined: Mon Apr 26, 2004 7:51 am
Location: Germany

Post by Mobsie »

Hi Rob Murphy,

i dont know what you wan't to say.

There are a lot of thinks you don't sea or read BUT this thinks are real.

The vic memory table is open for ALL people and ALL people can try what he wan't. I use this trick 15 years ago when i write my second game on vic-20.

I then go to C-64, then Amiga Atari Falcon030, Acorn Risc-PC and so on, and i lose a lot of code for my VC-20. But now years later it's fun on vc-20.

And i found an old listing where i use this trick. But when people think i will post here tricks from other people then i don't do post tricks in future.
I don't like when people think so about me.

Cheers an a nicy cristmas to all.
Mobsie
Boray
Musical Smurf
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Joined: Mon May 03, 2004 10:47 am

Post by Boray »

Mobsie wrote:But when people think i will post here tricks from other people then i don't do post tricks in future.
I don't like when people think so about me.
Don't think like that. I'm greatful for your tip!!! And it sort of indirectly says in the vic20 programmers reference guide that you can use the tape buffer for this purpose. It says you can use the zero page - and the tape buffer is in the zero page... You just figured out that the tape buffer could be used for anything...

Rob Murphy, You said you both run into this idea on another site, AND figured this out for yourself and posted it on that site???? Anyway... Even if both you and Mobsie figured it out, how many of the programming tips on any site do you think are posted by the original inventor????? If that would be required then I think this section would be rather blank.... And if you could figure it out, then why do you think that someone else couldn't????? Are you smarter than everyone else or something?

/Anders
PRG Starter - a VICE helper / Vic Software (Boray Gammon, SD2IEC music player, Vic Disk Menu, Tribbles, Mega Omega, How Many 8K etc.)
Rob Murphy
Vic 20 Drifter
Posts: 35
Joined: Fri Dec 17, 2004 8:14 pm

cassete buffer

Post by Rob Murphy »

Please, except my apology and it will never be brought up again. Just check the file. It was posted by the site master by my request two years ago. Read the text files and decide for yourself. An Idea like this would have swept through the unexpanded vic 20 population like wildfire. I remember all the articles on data crunching for vic users.

Here's the d/l site:

http://www.kdef.com/geek/vic/vicmemorysaver2.zip

Again, my apologies. I hope in the future we can trade new work.
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Jeff-20
Denial Founder
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Post by Jeff-20 »

:roll:
High Scores, Links, and Jeff's Basic Games page.
aneurysm
not your PAL
Posts: 178
Joined: Sat Mar 06, 2004 11:06 pm

Post by aneurysm »

you've never read the memory map in the Programmer's Reference Guide have you?
carlsson
Class of '6502
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Joined: Wed Mar 10, 2004 1:41 am

Post by carlsson »

Let's say both Mobsie and Rob are evangelists of the same message. Both are ~15-20 years past the era when the VIC was commercially interesting and thus a tip about how to get more out of unexpanded games had been highly valued.

For the record, there were listings and even commercial games already in 1983 who took advantage of putting graphics, code and other snippets somewhere into the low 1K. Personally, I think it is much sexier to cram down the video matrix there than just a mere few of UDGs. :wink:
Anders Carlsson

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Boray
Musical Smurf
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Post by Boray »

I had put code in the tape buffer before, so I had simply not thought of putting graphics there...

/Anders
PRG Starter - a VICE helper / Vic Software (Boray Gammon, SD2IEC music player, Vic Disk Menu, Tribbles, Mega Omega, How Many 8K etc.)
Rob Murphy
Vic 20 Drifter
Posts: 35
Joined: Fri Dec 17, 2004 8:14 pm

Using a Tape Deck and Custom Chars in Tape Buffer

Post by Rob Murphy »

OK, here's a good one for all of you that still might be using a cassette recorder and want to use that space for graphics (or ML).

POKE 179,4

This poke makes the screen into the tape buffer. It will more than likely garble the first couple of screen lines, so you'll have to work around that.

Locations 178 - 179 hold the address for the tape buffer.

I found this Idea for keeping ML intact in the buffer in the 1986 Special issue of RUN Magazine.

I'd also like to know if anyone else might have some other issues of RUN, Compute!, Compute's Gazette, Ahoy!, or other fine mags that were printed in the 80's and 90's.

That's all for now.

Rob
carlsson
Class of '6502
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Post by carlsson »

Hm, interesting idea. That poke would move the tape buffer from 828 to 1084 (i.e. into the +3K space, so you need a suitable memory expansion). Since the VIC-I can access the onboard RAM but not the cartridge expansion, you would move the non-critical tape buffer into a part of memory not useful for graphics anyway.

As an alternative, A=PEEK(56)-1:POKE 179,A:POKE 56,A

would theoretically move the tape buffer to the top of memory no matter how much RAM you have available, and all of the previous tape buffer space could be used for custom characters independent of memory configuration. Not tested, though.
Anders Carlsson

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Rob Murphy
Vic 20 Drifter
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Joined: Fri Dec 17, 2004 8:14 pm

cassette buffer

Post by Rob Murphy »

My bad, that poke was for a c64. the number for a Vic should be:

POKE178,0:POKE 179,30 <-- Unexpanded Screen Memory

I didn't even check to see if it worked. But I'm sure this one is right.

Thanks.

Rob
vic user
VicGyver
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Post by vic user »

i just want to say thanks again for this tip.

it might not be much, but it does give a 5x5 character hires display without having to fiddle with memory.

and combined with the program interrupts area, you can have ready made graphics, and poke them in (albeit taking up 64 pixels per character) on the fly.

i have been having a lot of fun trying to recreate Boray's snowfall routine within that tiny display.

chris
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