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0 pointsddingus6y ago0 comments

I am not the OP either, but 6502 and 6809 are my faves.

6502 was first. It is simple. And that makes it a lot of fun.

6809 is beautiful. I think it is the most powerful and elegant of the 8 bit CPUs. But that spoils a person too.

6502 is like whittling computing down to some useful nubs. There are enough subtleties to make it interesting too.

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6502 on a Vic20 was where I really learned to program. As a 12 year old in 1982, I quickly outgrew Basic (with 3583 bytes of free memory) and its 22x23 char screen. I saved my pocket money to buy the assembly language cartridge.

My two most memorable 6502 assembly projects were:

- Text-to-speech - GUI for entering rules to generate phonemes for a text-to-speech system

- 3D graphics - Switching the Vic-20's characters set from ROM to RAM so I could do high-resolution pixel-addressable graphics. I wrote a full set of 3D primitives to draw lines, circles, do perspective and rotations from 3D to 2D, all in 6502 assembly.

One summer holidays I transcribed the entire Vic-20 ROM disassemby into old exercise books, so I could learn how it worked. I remember a sense of victory after reverse-engineering the floating point format and how the transcendental math functions worked.

Happy days!

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