ALU is short for Arithmetic Logic Unit.
This is the place where the heavy duty power of the computer chip hums. In it are comparators, adders, barrel shifters, complimenters, transfer gates, registers and lots of control logic.
Some of the registers are pretty standard: (the following list is based on a CISC
In a RISC
ALU all the registers may have the same, though expanded, collection of functions.
Normal operations of an ALU are add, move, compare, branch, and, depending on the type, write and read.
are sometimes mapped
to memory locations.
The control unit
usually handles all the flow and decoding of tasks to do. Giving the ALU specific details on what to do.