If you have enough RAM, you can define an array. Then copy data (PEEK) from the ZX81 'display file' area of memory into the array.
When you save a BASIC program, variables including arrays are saved. When loading, do not use RUN, instead use GOTO 1. Then the array and the data in it is not lost. The screen data can then be copied (POKEd) back to the 'display file'.
To reduce the amount of memory needed, use a string array and convert the numbers returned by PEEK to characters.
This is only practical if your system has at least 16K RAM.
For more on this, read through chapter 22 and chapters 27 and 28 in the Sinclair ZX81 BASIC Programming manual.
Mark
Small memory dump program
- 1024MAK
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Re: Small memory dump program
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Re: Small memory dump program
Indeed there is a possibility: ZeddyNet and TNFSzxooner wrote: ↑Wed Sep 05, 2018 12:41 pm Is there any way that the data could be sent to the pc instead of a printer (thaf the 81 thinks is a printer) so the picture can be saved on the pc that way? I've pre-ordered the ZXpand+ and I was wondering if the possibility existed alongside a serial link.
My Zeddy has a patched rom, which does not have any printer routines inside. Instead it has an interface to external printer drivers in ram.
So I can load a printer driver into ram above 32K, which forwards printed data to
- a normal Sinclair printer
- a Centronics-Printer (via interface cards having e. g. a Z80 PIO)
- a network printer (a PC acting as TNFS server) somewhere in the internet
Usually I use the network printer to "print" into a file on my PC. All usual LPRINT, LLIST, COPY commands then write into a file (via ZeddyNet) on my PC.
Siggi
My ZX81 web-server: online since 2007, running since dec. 2020 using ZeddyNet hardware
http://zx81.ddns.net/ZxTeaM
http://zx81.ddns.net/ZxTeaM
Re: Small memory dump program
Thank you for the suggestions! I got a ram pack today and I was hoping to be able to have a bit more of an experiment with things with 16kb under my belt but sadly it's duff as I just get the white screen with it plugged in.
@mrtinb, apologies for hijacking your thread!
@mrtinb, apologies for hijacking your thread!
low res art for the Public Domain at the ArtBeSassy archive.
Re: Small memory dump program
You could start a new.
Re: Small memory dump program
low res art for the Public Domain at the ArtBeSassy archive.