User guide

24-113
SystemVerilog Testbench Constructs
a = 10; a1 = 3;
$display("Generating random numbers with urandom_range
with expressions in range");
//generating value of b between 7 and 3
b = $urandom_range((a-a1), a1); //expressions as
args to urandom_range
$display("value of b generated with range %0d and
%0d is %0d",a-a1,a1,b);
//generating value of b between 3 and 7
b = $urandom_range(a1,(a-a1));
$display("value of b generated with range %0d and
%0d is %0d",a1,a-a1,b);
$srandom(2); // changing the seed for thread
//generating value of b between 0 and 7 (omitting
one of the range value)
b = $urandom_range(a-a1);
$display("value of b generated with range %0d and
%0d is %0d",0,a-a1,b);
end
endprogram
The output of this program is:
Generating random numbers with urandom_range with
expressions in range
value of b generated with range 7 and 3 is 6
value of b generated with range 3 and 7 is 7
value of b generated with range 0 and 7 is 0
$srandom()
You can use the system function $srandom() to manually set the seed
for random number generation. The syntax is:
$srandom(seed)