When I was 14 back in the 90s, stuck in Australia with very little in the way of networks or even dead-tree documentation, I’d have sold my mother for this information :)
I hear you (I was also was 14 and stuck in Australia in the 90’s, desperately trying to find hardware programming information). I remember managing to get my hands on a 3.5” floppy with Mark Feldman’s “PC Games Programmer’s Encyclopaedia” (now reproduced online here and probably other places) and it being a treasure trove. The world moved on before I ever got either the hardware or the time to really put it to use.
I found a version of that on a BBS back in the day, that’s a trip down memory lane, thanks :)
Every few years I google around trying to find if that “DMA setpixel” might have been a real thing, but alas no dice.
No worries. :)
The DMAC datasheet contains pretty specific information on how to do memory-to-memory transfers but I’ve alternatively heard that (a) the chip isn’t wired up quite right to achieve it properly in the PC or that (b) it’s actually slow and it’s better just to copy pixels using the CPU. I never got around to verifying it, but I remember also trying to find out about it. I also vaguely recall someone writing up experiments where they managed to blank out pixels, but not actually copy, suggesting that (a) is the case, but I’ve no idea if they did it properly.