// Demo for "final" smtc constraints module demo4(input clk, rst, inv2, input [15:0] in, output reg [15:0] r1, r2); always @(posedge clk) begin if (rst) begin r1 <= in; r2 <= -in; end else begin r1 <= r1 + in; r2 <= inv2 ? -(r2 - in) : (r2 - in); end end endmodule