2009.11.16

module top;
wire [3:0]x_in;
system_clk #50 clkl(x_in[0]);
system_clk #100 clkl(x_in[1]);
system_clk #200 clkl(x_in[2]);
system_clk #400 clkl(x_in[3]);
and4_algo c1 (y_out,x_in);
endmodule


module and4_algo(y_out,x_in);
input[3:0] x_in;
output y_out;
reg y_out;
integer k;
always@(x_in)
begin:and_loop
y_out=1;
for(k=0;k<=3;k=k+1) if(x_in[k]==0) begin y_out=0; disable and_loop; end end endmodule module system_clk(clk); parameter period=100; output clk; reg clk; initial clk=0; always #(period/2)clk=~clk; always@(posedge clk) if($time>1000)
#(period-1)
$stop;
endmodule