Logic Gates: One-Bit ALU


1-bit ALU

Handles AND, OR, and binary addition. Handles binary subtraction by negating b and doing addition. (Flip all the bits and set CarryIn0 to 1 to compute two's complement.)

The Binvert control bit determines whether b or not b is passed to the adder.

The two Operation control bits determine which result is passed through the second MUX (AND, OR, or sum).

Stop and Think: Why is the Binvert control line 1 bit, while the Operation control line is 2 bits?

Alyce Brady, Kalamazoo College