This infers a combinatorial circuit since there is no clock. The case statement is like a switch statement in C. The funny looking numbers are four bit hex (4’h1) and 7 bit binary (7’b1101101).

This paper focuses on the implementation and simulation of 4-bit, 8-bit and 16-bit carry look-ahead adder based on Verilog code and compared for their performance in Xilinx.