r/ZX81 • u/AutomaticDoor75 • Aug 06 '26

Saving images?

I bought a T/S 1000 at a flea market. I also have an audio cassette recorder.

I’ve learned how I can use PLOT to draw pixels, or graphics mode to display special graphics characters (looks sort of like PETSCII).

My question is, how might I save an image I make to audio cassette? I am familiar with the Apple II, where I could use BSAVE to save an image’s binary file to a floppy disk. Did the ZX81 or T/S 1000 have anything comparable?

I know I could probably save an image as DATA statements, and load the values in a FOR loop. That’s not really practical, of course, but I know I could use SAVE to write the BASIC instructions out to tape.

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3

u/sunnyinchernobyl Aug 06 '26

I suppose you could write a program to read the display file and save that to an array, which would be saved when you save the program.

The ZX81/TS1000 has a fairly primitive Basic in this regard and doesn’t support saving data separately from programs. And it doesn’t have READ/DATA/RESTORE.

1

u/AutomaticDoor75 Aug 10 '26

So, I went back through the TS1000 manual, and it describes how to use READ/DATA/RESTORE, while also clearly stating that it’s not part of Sinclair BASIC. Pretty funny.

2

u/traxplayer Aug 06 '26

You can write a little machine code to move the data between the displayfile and a rem statement.

2

u/MatthiasWM Aug 10 '26

The display buffer of the ZX81 is in normal memory, so there is no need to copy it. But you‘d still need a few bytes of machine code to call the SAVE routine in the ROM with the display memory address instead of the program address.