Introduction - If you have any usage issues, please Google them yourself
1) requires the use of fast carry chain (Look Ahead) design a 21-bit adder
2) the use of structured design methods, all adders are used in step 1) 21-bit adder
3) was added in the adder array pipeline structure (Pipelinc), enter the number of continuous feed, continuous output the results after each shot output lines to fill a result