Ahh, 8 bit processors. Old, a bit slow, but with two great advantages:

1. They were cheap in the 80's and enabled a lot of home computers and video game systems to be sold at affordable prices. Cf. Sinclair, Commodore 64 and Gameboy.&

2. With only 256 instructions max, you could remember the ENTIRE machine code instruction set off by heart. This allowed programmers like me to write machine code DIRECTLY into memory without using an assembler.

See Z80 and 6502.