[TGTTGIT] recently took the plunge and decided to build his own computer using logic chips. He just completed a 4-bit ALU which can compute 18 functions. It took a long time to get the wiring right, ...

An earlier logic chip used as a building block for CPUs. Bit slice processors used arithmetic logic units (ALUs) that typically came in 4-bit increments, although 1- and 2-bit devices were also made.

Increment and decrement. They sound like simple functions. But even the simplest functions can get quite complex in a microprocessor design. Ken Shirriff has written up a great blog post about his ...