Still lacks the ST A, [addr] instruction, to save the contents of tha A register to the RAM (actually, the register has only 4 bits and each RAM cell is 8-bit, so it uses just the 4 less significant bits, and the other bits are set to 0, kind of odd, I know, but it's just a proof of concept).

I'm procrastinating a lot this last instruction, because I'm deeply buried in TTL research to the 2nd generation CPU, JACA-2...

Let's see what I chose so far:

-2x 74181 for ALU

-for registers: 74HC574

-for RAM: CY62256

What do you think about these choices? Would you use others?