ZX80/ZX81 virtual device for sld output

[stevexyz]

DeZog is using sld as sjasm best listing. "The SLD data are being exported only for machine code produced within one of the virtual devices". Willing to use it to develop for ZX80/ZX81 seems new device type is needed.

The ZX80/ZX81 are simple computers, and should not be difficult to add them. If someone will guide me to the places to intervene, I can even make a pull request for it in case.

[ped7g]

does zxspectrum48 cover these as sort of "superset" of zx80/81, or does the memory map differ enough to make zx48 map invalid for such use? (sorry for entry level question, I know next to nothing about ZX80 and ZX81, I have just seen them like 2-3 times in my life :) ).

[stevexyz]

Despite Spectrum has been my first computer, I had now to search to find information about it :)

Anyway, depending what you mean with "memory map", here some differences I can see:

• zx81 has 8k ROM (zx80 4k) while spectrum 16k (all starting at 0)
• if I got it properly zx spectrum video memory is strictly below the 32k; zx81 way to handle video has not this limit even if in not true-hires it is "executing" video memory in the upper 32k to display the data in the lower 32k (it is a bit complex to describe the tricks used for video display but I can elaborate further if needed)
• "standard" zx80 and zx81 have just 1kb of memory (from 0x4000 to 0x4400)
• both have no paging feature with standard expansions

Waiting for answer here I found in the documentation that there is a recent instruction that might even be used: "DEFDEVICE". Can this be good to be used?

 DEFDEVICE zx81, $4400, 1
 DEVICE zx81
...