硬件描述语言 ------- 两位元多功能选择器 (第五周)

程序代码:

module top;

  integer ia[1:0],ib [1:0];
  integer is;
  reg [1:0] a,b;
  reg s;
  wire [1:0] out;

 mux2  mc(out[1:0],a[1:0],b[1:0],s);

  initial

    for (ia[0]=0; ia[0]<=1; ia[0] = ia[0]+1)
        begin
          a [0]= ia[0];
  for (ia[1]=0; ia[1]<=1; ia[1] = ia[1]+1)
  begin
  a [1]= ia[1];
            for (ib[0]=0; ib[0]<=1; ib[0] = ib[0] + 1)
    begin
    b[0] = ib[0];
    for(ib[1]=0; ib[1]<=1; ib[1] = ib[1] + 1)
     begin
     b[1] = ib[1];
                   for (is=0; is<=1; is = is + 1)
                   begin
                      s = is;

                     #1 $display("a[0]=%d a[1]=%d b[0]=%d b[1]=%d s=%d   out[0]=%d out[1]=%d",a[0],a[1],b[0],b[1],s,out[0],out[1]);

                    end
                end
           end
     end
  end
endmodule
module mux2(OUT, A, B, SEL);
output [1:0] OUT;
input [1:0] A,B;
input SEL;
mux_behavioral hi (OUT[1], A[1], B[1], SEL);
mux_behavioral lo (OUT[0], A[0], B[0], SEL);
endmodule

module mux_behavioral(OUT, A, B, SEL);

 output OUT;
 input A,B,SEL;
 wire  A,B,SEL;
 reg    OUT;

  always @(A or B or SEL)

   OUT = (A & SEL)|(B & ~SEL );
endmodule