simulation clock gen unit (推荐)

//Normal Clock Block
always begin:clk_blk
  clk <=0;
  #10 clk<=1;
  #10;
end

//Improved Clock Block, improve clcok speed by 25%
always begin:clk_blk
   clk = 0;
   forever #10 clk = ~ clk;
end

1.use a forever loop in the always block

2.use blocking assignment

3.improves clock speed by 25%