z80 is a lovely instruction set, and a delight to work with. These days CPUs are incredibly complicated, with massive instruction sets, pipelining and caches, m

z80 is a lovely instruction set, and a delight to work with. These days CPUs are incredibly complicated, with massive instruction sets, pipelining and caches, microcode and SMP, lots of crazy nonsense going on. Anyone who has ever worked with the x86 family at a low enough level knows just how insane it is. z80, on the other hand, is just a reasonably fast CPU with predictable timings and an instruction set which can fit on an index card (well, if you use both sides). It still has plenty of secrets to discover, though - easily half of the instruction set is undocumented and full of useful tricks. I have spent a lot of time with this CPU, none of it wasted :)