//----------------------------------------------------------------------
// IAS0150 - Homework #2. Example task - #1, gates, no optimization.
//----------------------------------------------------------------------
// (C) Peeter Ellervee - 2026 - Tallinn
//----------------------------------------------------------------------
module fs_opti (input x1, x2, x3, x4, output y1, y2, y3, y4);
  logic x1i, x2i, x3i, x4i;
//logic t1, t2, t3, t4, t5, t6, t7, t8, t9;
  logic t1, t2i, t3, t4, t5i, t6, t7, t8, t9;
//logic t19, t68;
  logic t19, t68i;

  assign x1i = !x1;
  assign x2i = !x2;
  assign x3i = !x3;
  assign x4i = !x4;

  assign t1 = t4  & x1i & x3i;
//assign t2 = x1  & x3  & x4;
  assign t2i = !(x1 & x3 & x4);
  assign t3 = x2  & x3i & x4i;
  assign t4 = x2  & x4;
//assign t5 = x2i & x3;
  assign t5i = !(x2i & x3);
  assign t6 = t7  & x3;
  assign t7 = x1i & x4i;
  assign t8 = x1  & x2i & x4i;
  assign t9 = x1  & x3;

  assign t19 = t1 | t9;
//assign t68 = t6 | t8;
  assign t68i = !(t6 | t8);

  assign y1 = t19 | t3 | t7;
  assign y2 = !(t19 | t8);
//assign y3 = t3 | t4 | t68;
  assign y3 = t3 | t4 | (!t68i);
//assign y4 = t2 | t5 | t68;
  assign y4 = !(t2i & t5i & t68i);

endmodule