XSim implements 0 ** -1 incorrectly

[cliffordwolf]

The following module should return 8'bx for both outputs (see table 5-6 of IEEE Std 1364-2005):

module issue_019(y0, y1);
  output [7:0] y0;
  output [7:0] y1;
  assign y0  = 8'sd0 ** -8'sd1;
  assign y1  = 8'd 0 ** -8'sd1;
  initial #10 $display("%b %b", y0, y1);
endmodule

But XSim 2013.4 returns 8'b0 instead.

In my tests I have run this module with:

xvlog issue_019.v
xelab -R work.issue_019

Crosscheck: Modelsim 10.1d implements this correctly. Isim 14.7 has the same bug.

Note: This is a bug report. I don't need support.

[debrajr]

Thanks for posting. We would file bug report for this one and provide you the CR number.