module johnson_decode (q,decode);
 parameter Width = 16;
 input  [Width-1:0] q;
 output [(Width*2)-1:0] decode;
 reg    [(Width*2)-1:0] decode;
 integer i;

 always @(q)
  for (i=0;i<Width*2;i=i+1)
   if (i==0)
    decode[0] = !q[Width-1] && !q[0];
   else if (i==Width)
    decode[Width] = q[Width-1] && q[0];
   else if (i<Width)
    decode[i] = q[Width-i] && !q[Width-i-1];
   else //i>Width
    decode[i] = !q[Width-(i-Width)] && q[Width-(i-Width)-1];
endmodule