I wrote a 6502 emulator in Lua

https://github.com/willtobyte/MOS6502

Thread some years ago https://news.ycombinator.com/item?id=20732867

My VIC-20 coding trick as a 14 year old was to use the 828 byte cassette buffer for storage in my games because it took me forever to save up for the 6.5k RAM expansion.

One of the neatest things I've heard demo scene people do on the 6510/6502 is a "stack machine." I don't know exactly, but fwiw I understand, it works like this:

it's using the stack page, 256 bytes from 0x100 - 0x1ff. It generally stores two-byte pointers to code. When each routine finishes, it calls RTS and the CPU automatically pulls the next 16-bit addr from the stack and jumps to it. You never call JMP, JSR, etc, never pushing your address onto the stack! And I think you can also do tricky things like throw in some code executing in that space, too. And I think it can loop around, too, so you have a basic set up of 128 slots for routines that can switch between them very quickly. You can also write to the SP (stack pointer) to jump around in the slots.

p.s. pray you don't get any interrupts while this is going on unless you absolutely know what you're doing :)

Apologies if I haven't got this right. I've never seen it, only heard about it.

I remember the annoyance a lot of people had with the non-sequential layout of text/graphics memory on the Apple ][ (thanks to Woz’s clever hacks to reduce chip count), but when writing assembly code to access screen locations, it turned out that it was actually easier to deal with the somewhat weird arrangement of bytes than it would have if everything were sequentially arranged in memory. Those little 8-byte gaps every three (non-consecutive) rows made calculating row starts much simpler.