Functional Verification Blog

Here is the example. How you can change the seed for a class and generate different pattern with randc.
If you comment the line “obj.srandom(seed)” it will generate the same pattern again after the cycle.
Try compiling it again with commenting above line.

class randctest;
randc bit [1:0] randbit;
task print;
$display(”Rand C = %d”, randbit);
endtask
endclass

program main;

randctest obj;

initial begin
obj = new();
for (int i=0; i<12; i++) begin
if (i % 4 == 0) begin
obj.srandom(236+i);
$display(”==============”);
end
if (obj.randomize()) begin
obj.print();
end
else begin
$display(”Randomization failed \n”);
end
end
end
endprogram : main

Output :
==============
Rand C = 0
Rand C = 1
Rand C = 2
Rand C = 3
==============
Rand C = 2
Rand C = 1
Rand C = 3
Rand C = 0
==============
Rand C = 1
Rand C = 0
Rand C = 2
Rand C = 3

This entry was posted on Tuesday, September 9th, 2008 at 2:56 am and is filed under System Verilog. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.