用verilog编写的数据选择器：module multiplexer8_to_1(OUT,A2,A1,A0,D7,D6,D5,D4,D3,D2,D1,D0);  output  OUT;  reg OUT;  input D7,D6,D5,D4,D3,D2,D1,D0;  input A2,A1,A0;  always@(A2,A1,A0,D0,D1,D2,D3,D4,D5,D6,D7)  case({A2,A1,A0})      3'd0:OUT=D0;      3'd1:OUT=D1;      3'd2:OUT=D2;      3'd3:OUT=D3;      3'd4:OUT=D4;      3'd5:OUT=D5;      3'd6:OUT=D6;      3'd7:OUT=D7;    default:$display("Unspecified control signal");endcaseendmodule          module stimulus;  reg a2,a1,a0;    reg d7,d6,d5,d4,d3,d2,d1,d0;    wire out;    multiplexer8_to_1 mymux(out,a2,a1,a0,d7,d6,d5,d4,d3,d2,d1,d0);initialbegind7=1;d6=1;d5=0;d4=0;d3=1;d2=0;d1=1;d0=0;#10 $display ("   d7=%b,d6=%b,d5=%b,d4=%b ,d3=%b,d2=%b,d1=%b,d0=%b\n", d7,d6,d5,d4,d3,d2,d1,d0);a2=0;a1=0;a0=0;#10 $display("a2=%b,a1=%b,a0=%b,out=%b\n",a2,a1,a0,out   );a2=0;a1=0;a0=1;#10 $display("a2=%b,a1=%b,a0=%b,out=%b\n",a2,a1,a0,out);a2=0;a1=1;a0=0;#10 $display("a2=%b,a1=%b,a0=%b,out=%b\n",a2,a1,a0,out);  a2=0;a1=1;a0=1;#10 $display("a2=%b,a1=%b,a0=%b,out=%b\n",a2,a1,a0,out);                                                    a2=1;a1=0;a0=0;#10 $display("a2=%b,a1=%b,a0=%b,out=%b\n",a2,a1,a0,out);a2=1;a1=0;a0=1;#10 $display("a2=%b,a1=%b,a0=%b,out=%b\n",a2,a1,a0,out);a2=1;a1=1;a0=0;#10 $display("a2=%b,a1=%b,a0=%b,out=%b\n",a2,a1,a0,out);a2=1;a1=1;a0=1;#10 $display("a2=%b,a1=%b,a0=%b,out=%b\n",a2,a1,a0,out);endendmodule。