I loved assembly language, the first program I wrote was a z80 routine to write a sprite to the screen, the second was to move it from one side to another. It didn't work, the sprite was always on the opposite side. After half an hour head scratching, I realised that it was actually moving the sprite across the screen so fast, it was doing it within a frame fly-back... the power of it knocked me off my seat.
Ah, NMI's, great for raster bar effects!
