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People, tell me this... How do you manage to write stuff like LAVA,
ZOOM/ROTATE, etc. with such crooked addressing of screen memory as in Zx?
And how did grandpa Clive even come up with the idea to make it like this?... :(

In a letter dated Thursday July 31, 1997, Max Polunin reported to All:

MP> People, tell me this... How do you manage to write stuff like
MP> LAVA, ZOOM/ROTATE, etc. with such a crooked addressing of screen memory as in
MP> Zx? And how did Grandpa Clive even come up with the idea to make it like this?...
MP> :(

He’s far from being a grandpa yet :)

This idea came to him because this kind of memory organization
provides minimal expenditure on fine-grained logic for development. But, of course, it was possible
to spend money on logic, but to make a normal video memory.

With respect, Andrew. Thursday July 31 1997 12:16.

MP>> type LAVA, ZOOM/ROTATE, etc. with such crooked addressing of screen memory
MP>> as in Zx? And how did grandpa Clive even come up with the idea to make her
MP>> like this?... :(
AM>
AM> He’s far from being a grandpa yet :)
AM>
AM> This idea came to him because it’s this kind of organization
AM> of memory that ensures the minimum expenditure of small logic on development. But,
AM> of course, it was possible to spend money on logic, but make a normal
AM> video memory.

And you look at the screen addresses in bit representation! You will see that each group of bits has its own secret meaning :) One indicates the third number of the screen, the other indicates a row, etc. I recommend reading any book on programming in machine code for the Z-80 - everything is described in detail there!
By the way, as they wrote in some computer publication (I don’t remember which one) - it is precisely
thanks to such a cool organization of video memory on the Specky that it is so easy to write programs! For example, when I switched from "PRAVETS-8D" (that was a long time ago, damn it :)), I was also scared at first by such an "idiotic" distribution! After consistent
on Pravets! But then I figured it out - I liked it!!!
It is incredibly simple and quick to do conversions from address to coordinates and
back!!! That's it!

Sincerely,Yuri.