UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

cancel
Showing results for 
Search instead for 
Did you mean: 
Contributor
Contributor
5,054 Views
Registered: ‎12-29-2013

XSim implements 0 ** -1 incorrectly

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.

0 Kudos
1 Reply
Moderator
Moderator
4,919 Views
Registered: ‎04-17-2011

Re: XSim implements 0 ** -1 incorrectly

Thanks for posting. We would file bug report for this one and provide you the CR number.
Regards,
Debraj
----------------------------------------------------------------------------------------------
Kindly note- Please mark the Answer as "Accept as solution" if information provided is helpful.

Give Kudos to a post which you think is helpful and reply oriented.
----------------------------------------------------------------------------------------------
0 Kudos