Here’s an example Verilog code to implement a 4-bit half adder circuit:
module half_adder (output sum, carry, input a, b);
assign sum = a ^ b;
assign carry = a & b;
endmodule
This code defines a module called “half_adder” that implements a 4-bit half adder. The output “sum” represents the sum of the two 1-bit inputs “a” and “b”, and the output “carry” represents the carry-out of the addition operation.
The “assign sum = a ^ b;” statement is a combinational logic statement that calculates the sum of the two inputs “a” and “b” by performing an exclusive OR operation.
The “assign carry = a & b;” statement is a combinational logic statement that calculates the carry-out of the addition operation by performing a logical AND operation.
Note that this Verilog code assumes that the “a” and “b” inputs, “sum” and “carry” outputs are all 1-bit signals. If you want to use multi-bit signals, you would need to modify the code accordingly. Additionally, this code implements a combinational circuit, which means that the outputs are updated immediately when the inputs change. If you want to implement a registered half adder, you would need to modify the code accordingly.