module MULT32; wire VDD = 1 ; wire VSS = 0 ; wire X00, X31 ; reg [1:0] state ; assign {X31, X00} = state ; ADDERXY XX1 (VSS, N1110, VSS, N2166, X00, X31); /* This one! */ ADDERXY XX127 (N1076, N1044, N2131, N2100, VSS, VSS); initial begin state = 0 ; $monitor( X00, X31, VSS, VSS,,, N2166, N1110 ) ; #10 state = 1 ; #10 state = 0 ; #10 state = 1 ; #10 state = 0 ; #10 $finish(0); end endmodule module ADDERXY( cin, cout, b, sum, x, y ); input cin, b, x, y; output cout, sum; reg [1:0] total ; assign sum = total[0] ; assign cout = total[1] ; always @ (x or y or b or cin) begin total = ( x & y ) + b + cin ; end endmodule // ADDERXY