Adder--Carry Look Ahead

The adder unit will consist of two cascaded 4-bit carry look ahead adder. There are several fundamental units:

1. P/G generator:
   Pi = Xi + Yi; Gi = Xi * Yi;
2. Sum generator:
   Si = Ci-1 xor Xi xor Yi = Ci-1 xor Pi (if choose Pi = Xi xor Yi);
3. Carry generator: Ci = Gi + Ci-1 * Pi;
   We choose to use 4-bit Manchester adder with carry bypass.

Shifter

GT, EQ and LT

SQRT