`ifdef FORMAL `define assume(_expr_) assume(_expr_) `else `define assume(_expr_) `endif module top(input clk, input [4:0] addr, output reg [31:0] data); reg [31:0] mem [0:31]; always @(posedge clk) data <= mem[addr]; reg [31:0] used_addr = 0; reg [31:0] used_dbits = 0; reg initstate = 1; always @(posedge clk) begin initstate <= 1; if (!initstate) begin //`assume(data != 0); //`assume((used_dbits & data) == 0); end end endmodule