hb4.tdf

来自「各种VHDL的开发资料」· TDF 代码 · 共 28 行

SUBDESIGN hb4
(
   clk,d[10..0]			:INPUT;
   q[3..0],sel[1..0]	:OUTPUT;
)

VARIABLE
   count[1..0]:	DFF;
BEGIN
   count[].clk=clk;
   sel[]=count[].q;
   
   IF(count[].q==2) THEN
      count[].d=0;
   ELSE
      count[].d=count[].q+1;
   END IF;
   
   CASE count[].q IS
      WHEN 0 =>
                q[]=d[3..0];
      WHEN 1 =>
                q[]=d[7..4];
      WHEN 2 =>
                q[2..0]=d[10..8];
   END CASE;  
END;