Re:Dirty tricks 6502 programmers use
by stevesimmons on Monday August 19, 2019 @02:56AM
(#20735504)
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!
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.