[sv-bc] RE: Q: case selector wildcards in a localparam?

The '?' character in a numeric literal is simply the same as 'z'. It doesn't make any difference to the compiler.

It's the statements like casez or operators like ==? that treat the 'z' state as a don't-care.

From: owner-sv-bc@eda.org [mailto:owner-sv-bc@eda.org] On Behalf Of Seligman, Erik
Sent: Wednesday, July 02, 2014 9:46 AM
To: sv-bc@eda.org
Subject: [sv-bc] Q: case selector wildcards in a localparam?

Should the code below be legal?   I was surprised to find that some compilers accept it, though my interpretation of the standard is that the localparam needs to be a constant.


module localparam_case (input logic [7:0] i1,input logic clk,rst, output logic [7:0] o1);

localparam ugly =  7'b110_1???;

default clocking @(posedge clk); endclocking
default disable iff rst;

always_comb begin
casez (i1)
  ugly: o1 = 0;
  default: o1 = i1;
endcase
end

a1: assert property (o1 == i1);

endmodule


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