Implement a 4-bit carry-lookahead adder using SystemVerilog.

Sure, here’s an example of a 4-bit carry-lookahead adder implemented using SystemVerilog:

module carry_lookahead_adder_4bit(
  input logic [3:0] a,
  input logic [3:0] b,
  input logic cin,
  output logic [3:0] sum,
  output logic cout
);

  logic [3:0] p, g, c;

  assign p = a ^ b;
  assign g = a & b;
  assign c[0] = cin;
  assign c[1] = g[0] | (p[0] & c[0]);
  assign c[2] = g[1] | (p[1] & c[1]);
  assign c[3] = g[2] | (p[2] & c[2]);
  assign cout = g[3] | (p[3] & c[3]);
  assign sum = p ^ c;

endmodule

In this code, we define a module called `carry_lookahead_adder_4bit` with three input ports `a`, `b`, and `cin`, and two output ports `sum` and `cout`. The `a` and `b` inputs are 4-bit binary values representing the addends, the `cin` input is a single-bit binary value representing the carry-in signal, the `sum` output is a 4-bit binary value representing the sum of the addends, and the `cout` output is a single-bit binary value representing the carry-out signal.

The `p`, `g`, and `c` signals are 4-bit binary values representing the propagate, generate, and carry signals, respectively.

The `assign` statements use the bitwise XOR (`^`) and AND (`&`) operators to implement the carry-lookahead adder functionality. The `p` signal is set to the bitwise XOR of the `a` and `b` inputs, representing the propagate signals. The `g` signal is set to the bitwise AND of the `a` and `b` inputs, representing the generate signals.

The `c[0]` signal is set to the value of the `cin` input, representing the carry-in signal. The `c[1]` through `c[3]` signals are set using the following carry-lookahead equations:

c[1] = g[0] | (p[0] & c[0])
c[2] = g[1] | (p[1] & c[1])
c[3] = g[2] | (p[2] & c[2])

The `cout` signal is set to the bitwise OR of the `g[3]` signal and the bitwise AND of the `p[3]` signal and the `c[3]` signal, representing the carry-out signal. The `sum` signal is set to the bitwise XOR of the `p` signal and the `c` signal, representing the sum of the addends.

You can instantiate this module in your top-level design hierarchy and connect it to other modules or input/output signals as needed. Note that you can modify the code to implement an adder with a different number of bits by changing the bit width of the input and output signals, and modifying the adder logic accordingly.