CARRY_SUM Primitive

The CARRY_SUM primitive is a two-input, two-output primitive that designates the carry-out and sum-out logic for a function. The cout port of the primitive acts as the carry-in for the next element of the carry chain. The carry function implements fast carry-chain logic for functions such as adders and counters.

When you use a CARRY_SUM primitive, you must observe the following rules:

You can direct the Compiler to automatically insert CARRY_SUM primitives during logic synthesis with the Auto Carry Chains logic option.

Note: For information about Quartus® Prime Standard Edition primitive instantiation, go to Using a Quartus® Prime Standard Edition Logic Function.