module top ( out, out1, clk, in ); output [7:0] out; output [7:0] out1; input signed clk, in; reg signed [7:0] out; reg signed [7:0] out1; always @(posedge clk) begin `ifndef BUG out <= out >> 1; out[7] <= in; `else out <= 8'bZZZZZZZZ; `endif end always @(posedge clk) begin out1 <= out1 >> 1; out1[7] <= in; end endmodule