2020 Logice Design Exam2
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###### tags: `verilog` `邏輯設計` `邏設` `digital design`
1. Suppose `A` is a 4-bit binary number declared with type wire. How can we assign a value of 3 to it? Please write down the code fragment. (2pts)

2. Suppose `B` is a 4-bit binary number declared with type reg. How can we assign a value of 3 to it? Please write down the code fragment. (2pts)

3. What is the difference between `!` and `~` ? Please explain it with an example.(2pts)

4. What is the function of the following code.(Hint. Why should we add the following code in a testbench?) (3pts)

module tb();
  initial begin
    $fsdbDumpfile("as4.fsdb");
    $fsdbDumpvars;
  end
  
  //...
endmodule

5. Describe the following circuit in Verilog. (3pts)


module comparator( A, B, gt, lt, eq );
    input A, B;
    output gt, lt, eq;
    
    wire negA, negB;
    
    assign negA = ~A;
    assign negB = ~B;
    
    assign gt = ...;
    assign lt = ...;
    assign eq = ...;
    
endmodule