Vertical Scroller by mistake

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mrtinb
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Vertical Scroller by mistake

Post by mrtinb »

Hi :)

I was trying to type in my first Forth program from paper, when all of a sudden Toddy Forth is doing a vertical scroller.

Somehow some of the video routine must have been messed with by mistake.

It is reproducible if you type in what I did.

Just out of curiosity; what is going on?

http://youtu.be/m199AhamaxY
Martin
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rune
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Re: Vertical Scroller by mistake

Post by rune »

mrtinb

I can reproduce the word SHOW. This is just showing the contents of the 620 memory locations allocated to SHOW. The characters displayed arent exactly the same but that may be because were are using different hardware or emulators.

Im not sure what you are trying to achieve with the second (scrolling) line. You are putting 77 and the contents of the first cell of SCR-FILE onto the stack, but what does the second graphic character represent? I dont have the Toddy manual.

edit to say I get OK when I reproduce the characters in zx 81 emulator
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mrtinb
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Re: Vertical Scroller by mistake

Post by mrtinb »

rune wrote: I can reproduce the word SHOW. This is just showing the contents of the 620 memory locations allocated to SHOW. The characters displayed arent exactly the same but that may be because were are using different hardware or emulators.

Im not sure what you are trying to achieve with the second (scrolling) line. You are putting 77 and the contents of the first cell of SCR-FILE onto the stack, but what does the second graphic character represent? I dont have the Toddy manual.
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Code: Select all

CREATE SCR-FILE 620 ALLOT
OK
: SHOW SCR-FILE @ 620 OVER + SWAP DO
  I @ EMIT LOOP ;
OK
SHOW
OK
77 SCR-FILE @ !
I realize the first mistake I made was adding a @ on the first line in the SHOW routine. This takes the content of first address of SCR-FILE, and uses that as start address for the array. So it should be:

Code: Select all

: SHOW SCR-FILE 620 OVER + SWAP DO
  I C@ EMIT LOOP ;
And the last command has the same problem, of using the content of the array as an address. It should have been:

Code: Select all

77 SCR-FILE C!
This would save an 'M' on the first location in the array.

I thought it was amazing that somehow I corrupted the memory so much I made it scroll. (Looking at the running code in an emulator I might find out what code is running.)
Martin
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ZX81, Lambda 8300, Commodore 64, Mac G4 Cube
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mrtinb
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Re: Vertical Scroller by mistake

Post by mrtinb »

Now I've come so far as having a little editor. It's all on paper, and works nice on the ZX81 as well.

Unfortunately I still cannot save my programs, as I don't have an old tape recorder. I can only load from wave file on my iPhone.

This means I start development by typing in the software from paper again. :roll: It can't get any closer to the old feeling of typing and typing :D
Martin
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Re: Vertical Scroller by mistake

Post by rune »

Cant you use an emulator and save the image when needed. Once you have the program working save and convert to a wav for use on the real hardware.

Benschop Forth 83 is very good, but its for the Spectrum. You can save to tape, microdrive, IF1bis or any other media storage thats compatible with the 48K.

I also like h4th for the ZX81
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mrtinb
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Re: Vertical Scroller by mistake

Post by mrtinb »

rune wrote:Cant you use an emulator and save the image when needed. Once you have the program working save and convert to a wav for use on the real hardware.
Yes, that's possible. But I feel the joy of using a ZX81 is not in an emulator. It's about using the machine. (Now, that I've created a keyboard and all.)
rune wrote:I also like h4th for the ZX81
All these problems will be solved when the ZXblast is made. Then I'll buy one, and save to USB-stick. Using a different ROM with the ZXblast like H4TH will be possible as well.

Maybe I'll find a cassette recorder next week. This weekend all I could find was a reel-to-reel tape recorder.
Martin
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rune
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Re: Vertical Scroller by mistake

Post by rune »

Good luck with the search.

I agree on using real hardware, but sometimes (most times) its easier to use an emulator when the TV is rubbish but she who must be obeyed is watching it.
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Re: Vertical Scroller by mistake

Post by gammaray »

but she who must be obeyed is watching it.
I feel live your pain.
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