Question

Assume the following about the number of gates and propagation delays for various adder circuits. a full adder circuit has 9 gates and a propagation delay of 2 ns. a 4-bit cla (carry lookahead) adder has 48 gates and a propagation delay of 5 ns. an 8-bit cla adder has 133 gates and a propagation delay of 5 ns. a 16-bit hierarchical cla (hcla) adder has 219 gates and a propagation delay of 10 ns.

Which type of adder has the highest number of gates?

a) Full adder circuit

b) 4-bit carry lookahead (cla) adder

c) 8-bit carry lookahead (cla) adder

d) 16-bit hierarchical carry lookahead (cla) adder

Answer 1

The 16-bit hierarchical carry lookahead (HCLA) adder has the highest number of gates at 219.

Step-by-step explanation:

The type of adder with the highest number of gates is the 16-bit hierarchical carry lookahead (HCLA) adder. When comparing the number of gates listed for each type of adder, the 16-bit HCLA adder has 219 gates, which is more than the 8-bit CLA adder (133 gates), the 4-bit CLA adder (48 gates), and the full adder circuit (9 gates).

The adder with the highest number of gates is the 16-bit hierarchical carry lookahead (cla) adder. It has 219 gates, while the full adder circuit has 9 gates, the 4-bit cla adder has 48 gates, and the 8-bit cla adder has 133 gates. Therefore, option d), the 16-bit hierarchical cla adder, has the highest number of gates.